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The Mediterranean region has been identified as one of the main climate change hotspots: its sensitivity to global change is high and its evolution remains uncertain. The region experiences many interactions and feedbacks at the oceanic, atmospheric, and hydrological levels, while facing high anthropogenic activities. Analysing the water cycle over the Mediterranean region is of major importance to environmental and socio-economic aspects. The satellite monitoring of the Mediterranean water cycle represents one of the key challenges for the hydrological community.The presentation will show recent results on using satellite soil moisture and precipitation products for hydrometeorological prediction in the Mediterranean region, and particularly for the prediction of floods and landslides. Specifically, we will show the comparison of multiple satellite precipitation products for predicting flood in 100+ basins over the Mediterranean Basin by also using different hydrological models. Moreover, the assessment of satellite precipitation products for predicting the occurrence of landslides in Italy is carried out. Among the investigated satellite products, we have firstly considered state-of-the-art products such as TMPA (TRMM Multisatellite Precipitation Analysis), GPM (Global Precipitation Measurement), and H SAF (EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management). Secondly, we have tested the innovative products using the SM2RAIN algorithm for rainfall retrieval from multiple satellite soil moisture products including ASCAT (Advanced SCATterometer), SMOS (Soil Moisture and Ocean Salinity mission) and SMAP (Soil Moisture Active and Passive mission). [ABSTRACT FROM AUTHOR]

Hydrological models have been largely developed in the last 40 years achieving great advances in our capability to simulate hydrological processes at high resolution in the horizontal and vertical domains. In principle, physically-based hydrological model are able to reproduce fluxes and states with high accuracy. However, in the real world, our models strongly depend on the parameterization and on the input data used. Uncertainties in the parameterization and in the inputs are translated into the model, and even highly accurate models, in terms of physical representation of processes, will totally fail due to error in the parameterization and the inputs.This well-known problem is much more important in locations and regions in which the human impact on the hydrological cycle is more pronounced. Specifically, irrigation is the larger consumer of water worldwide and, in some regions, irrigation during the summer season is by far the major component of the hydrological cycle (i.e., if compared with precipitation and evapotranspiration). In recent years, specific parameterizations for including the irrigation process have been added to hydrological and land surface models, but typically they rely on theoretical conditions (e.g., constant irrigation rates when soil moisture is below to certain values) that might not occur in the reality. Therefore, we strongly need irrigation observations for correctly simulate the hydrological cycle in these regions.Very recently, we developed an approach for quantifying irrigation water from space by using satellite soil moisture observations (Brocca et al., 2018). The approach has been found successful at some locations in Iran, Spain, United States and Morocco, and now is being improved by using high resolution soil moisture products from Sentinel-1 and from downscaling techniques. The obtained irrigation estimates are used as input into hydrological modelling and their impact in terms of evapotranspiration and runoff fluxes is assessed. Results will be shown in basins in Spain and Italy, and presented at the conference.REFERENCEBrocca, L., Tarpanelli, A., Filippucci, P., Dorigo, W., Zaussinger, F., Gruber, A., Fernández-Prieto, D. (2018). How much water is used for irrigation? A new approach exploiting coarse resolution satellite soil moisture products. International Journal of Applied Earth Observation and Geoinformation, 73C, 752-766, doi:10.1016/j.jag.2018.08.023. [ABSTRACT FROM AUTHOR]

Mineral dust particles interact with the Earth's Climate System by absorbing and scattering solar and terrestrial radiations. Deposition of dust on open oceans provides nutrients for phytoplankton blooming. These interactions may feedback on dust emissions mostly through modulation of the hydrological cycle. Several studies have documented the failure of CMIP5 models to reproduce long-term variability of dust concentration, which may be related to vegetation changes in response to perturbations in the hydrological cycle. Because vegetation and its characteristics are affected by both direct human influences (e.g. deforestation) and climate change (e.g. dieback due to drought), it is important to include vegetation dynamics as one of the predictors of dust emission to accurately simulate past, present, and future dust forcing.The new GFDL Earth's System Model (ESM) version 4 contains fully interactive and consistent dust life cycle: from its emissions calculated by the dynamic land model (LM4.1) to its long-range transport in the atmospheric model (AM4) followed by its deposition to the ocean where it feeds the tracers of the bio-geochemistry model (COBALT). In this poster, we present an analysis of the amplification of dust forcing by vegetation and land-use changes, and its consequences on radiative forcing and ocean productivity, based on GFDL ESM4 simulations in support of CMIP6. [ABSTRACT FROM AUTHOR]

A key challenge in the projection of climate change (CC) impacts on hydrological hazards is the uncertainty, mainly from climate projections and hydrological modelling. Therefore, it is state of the art to use multi-model ensemble (MME) based information for quantifying potential CC impacts. A considerable amount of studies have been done based on these MMEs. However, little attention has been paid on how to best utilize MME derived information in CC risk management and adaptation. This type of research is done best jointly by data providers and users. The major objective of the CO-MICC project is to co-develop methods for providing and utilizing multi-model ensemble data on freshwater-related hazards computed by global hydrological models (GHMs) for risk and adaptation assessments. The project covers various spatial scales, and it provides CC risk and adaptation knowledge on a web portal. We aim to increase availability and applicability of salient and credible information for different types of end-users, with focus on how to embrace uncertainties. The project focuses on three spatial scales; global, transboundary (Morocco: Moulouya basin, Algeria: Chelif basin, and Tunisia: Mejerda basin) and basin (Ebro River basin, Spain). At each scale, two to three expert workshops will be carried out to facilitate the co-development of methods to utilize MME based information. At the global scale, we co-develop better methods in collaboration with international companies. The presentation is to share the first results of the focus basins along with a concise introduction to the CO-MICC project and its methods. For testing the validity and applicability of GHM outputs, streamflow simulated by four GHMs (WaterGAP, LPJML, CWatM, ORCHIDEE) driven by observation-based historical meteorological data (GSWP3) is compared to observed streamflow, and the relevance of this type of comparison for estimating the impact of climate change on streamflow is discussed. Accordingly, the climate change impact on the hydrological cycle is assessed using two indicators. 1) sensitivity of annual streamflow to inter-annual precipitation variability and 2) inter-annual variability of annual streamflow. In two expert workshops, user needs, as well as suitable hydrological hazard indicators, were identified. In addition, the experts provided feedback on potential ways for the presentation of hazards regarding precipitation, streamflow and renewable water resources by tables and maps. Outcomes of these expert workshops will be presented. [ABSTRACT FROM AUTHOR]

As a typical alpine marsh wetland on the Qinghai-Tibet Plateau, the Zoige Wetland plays an important role in the water source recharge of Yellow River. Meanwhile, it is more sensitive to climate change. Therefore, it is necessary to study the hydrological cycle of Zoige Wetland and the impact of climate change, which will also provide important support and reference for the study of hydrological process, and protection of wetland water resources in Alpine areas. Based on the distributed hydrological model, this paper analyzed the runoff process in the Zoige wetland basin, and explored the trend of runoff variation in the Zoige wetland basin under different climate change scenarios in the next 30 years from 2020 to 2050. The impact of climate change on wetland runoff were also discussed. Results showed that the runoff in the Zoige Wetland basin decreased under the future climate change scenario. The rate of runoff reduction was the largest in Machu station, followed by Zoige station, and finally Tangke station. The reduction in non-flooding runoff is significantly higher than that in the flood season. The runoff during non-flood season in the Zoige Wetland basin from 2020 to 2050 will decrease by more than 25% in the future climate change scenario. The sharp decline in non-flooded runoff may have an impact on the protection of the Zoige Wetland and the management of water resources in the middle reaches of the Yellow River and downstream areas. This poses more stringent requirements for the protection of the Zoige Wetland in response to future climate change. Under future climate change scenarios, how to strengthen the management and protection of wetland water resources and prevent the degradation and atrophy of wetlands is the issue we need to further discuss and consider. [ABSTRACT FROM AUTHOR]

It is the first time that I have the opportunity to work for 15 lessons in a Science laboratory with a group of 20 students. These students are 11 to 14 years old, so their prerequisites differ a lot. That is why I decided to start this project asking them some questions to stimulate their interest.1st question: What is the weather like where do you live today and which are the exogenous agents connected to it?The first part of the project consists in experimenting into the laboratory both the physical and chemical concepts that will be necessary to understand dynamic processes. Via laboratory experiments, we will introduce concepts like pressure, temperature, water cycle, density. If necessary, students will develop data and draw graphs. These concepts will be useful to describe exogenous agents and find out that the sun is the one that gives the engine.2nd question: Where in the Earth does the heat come from, and which are the endogenous agents?The second part of the project consists in studying and explaining Earth structure, Plate tectonics and earthquakes position on the maps, looking at videos and power point presentations. These contents will enable the students to formalize endogenous agents and find out that is the radioactive core that heats.3rd question: Now compare and analyse. Which are the areas where it is possible to connect climate and geological substrate?The third part of the project consists in analysing and comparing a climate map and a Plate tectonic map of the Earth. For instance, it will be possible to associate desert zones with craton ones. The final aim consists in producing a scheme that makes a correlation cause – effect between exogenous agent and endogenous ones and revers.4th question How would it be to live on an Earth without earthquakes, as well as without tectonic Plate?Now it is possible to find out the answer to our main question: Life is possible because of earthquakes!We could change this question and say:"Would it be possible to live on Earth without earthquakes?" [ABSTRACT FROM AUTHOR]

Hydrology, to date, has confronted its developmental bottleneck due to lack of newmonitoring and experimental data for hydrological processes in watersheds. Fortunately, newconcepts and techniques have been emerging to better meet the demands in the acquisition ofnew monitoring and experimental data. In addition, some artificial experimentalcatchments or watersheds, whose boundaries and inner structures can be designed anddefined in advance, have been established to investigate hydrological processes underwell-controlled conditions. In order to clarify the mechanism and regularity ofwatershed hydrological cycle, this study designs hydrological experiments withcoupled natural and artificial system using two-direction multi-scale approach, i.e.upward and downward. Thus, hydrological experiments at Huashan Watershed inChuzhou City, representative of the low-altitude warm region in China, are designedand being performed by adopting new and advanced monitoring techniques andequipments. Within Huashan Watershed with a drainage area of 80.0 km2, two representativewatersheds are selected: Sanchahe Watershed (17.6 km2) and Huangwa Watershed (2.6 km2).Four smaller catchments act as critical zone experimental blocks, including WangyingCatchment (0.27 km2), Gaochong Catchment (0.08 km2), Nandadish Catchment (0.008 km2)and Hydrohill Catchment (artificial, 0.0005km2). These catchments or watersheds jointogether to form an excellent multi-scale experimental system, including artificial and naturalexperimental blocks. At the outlets of Wangying, Gaochong, Huangwa, Sanchahe, andHuashan watersheds, V-notch weirs grooves and hydrological cables have been combined toobserve total stream discharges. Hydrohill and Nandadish catchments have been wellinstrumented to automatically measure hydrological elements such as precipitation,discharge, soil moisture, groundwater level, and evapotranspiration with high precision. Inaddition to the above measurements of water quantity related hydrological elements,precipitation, stream water, soil water, and groundwater in Hydrohill Catchment,Nandadish Catchment, Sanchahe Watershed and Huashan Watershed are sampled atdifferent location through water sampling systems designed and manufactured byourselves to determine the δ2H, δ18O, EC, pH, DO, and concentration of mainions. Hopefully, the experimental work and results in this site may push forward the emergenceof new data, new discoveries and new ideas for the development of hydrology, especiallyhydrological models. Key words: hydrological experiment; Nandadish; Hydrohill; Chuzhou HydrologicalExperimental Site; coupled natural and artificial system Acknowledgements: This study is supported by the National Natural Science Foundationof China (No. 91647203, 91647111, 41330854 and 41371063) and the Science Foundation ofNanjing Hydraulic Research Institute (No. Y516027, Y516032 and Y517016). [ABSTRACT FROM AUTHOR]

Water transport from the surface to Earth's deep interior and its circulation plays significant roles in understanding the dynamics of the planet, while the subduction process is a critical way to bring water to the mantle. It remains widely debated about how and how much water could be carried to the deeper mantle, e.g. the mantle transition zone or even the lower mantle. On the other hand, it is still unclear whether and how the recycled water interacts with the overriding craton and modifies its thermo-rheological properties as well as chemical compositions. In order to investigate the aqueous fluid/melt activities in the subduction zones, systematic numerical models are constructed, which integrate the thermomechanical models with petrological thermodynamic datasets of water solubility down to the lower mantle depth, i.e. 0-30 GPa. The models reveal that the amount of water carried by oceanic crust to the mantle transition zone is rather limited. A significant amount of water can be carried by the hydrated mantle rocks to the transition zone, which requires a relatively thicker hydrous mantle layer and faster subduction in order to pass through the 'choke point' in the phase diagram. The aqueous fluid in the high pressure hydrous phases may be stable in the mantle transition zone for a certain time, which will be released with the increased temperature and then go upward, passing through the big mantle wedge and then interacting with the overriding craton. The modification of the overriding craton generally occurs in the lower part of the lithosphere due to the hydration and partial processes, which may finally lead to the significant weakening and thinning of the cratonic lithosphere and extensive magmatism. [ABSTRACT FROM AUTHOR]

Space-borne microwave radiometers can be used to observe global snow precipitation, which plays an important role in energy balance and water cycle. However, lack of knowledge on complex microphysics of snow particles hampers snowfall parameterization in numerical weather prediction and climate models. Dual polarized microwave radiometer could offer specific information on snow micro-physical parameters, compared to traditional microwave radiometers with one-single polarization. Therefore, microwave polarimetry will be beneficial to snowfall detection. This study focuses on polarized signals originating from snow precipitation at millimeter-wave band, in order to gain a deeper insight into snow microphysics. The relationship between observed brightness temperatures and polarized signals (TB-PD) is built up with explanations from radiative transfer simulations. The existing space-borne microwave radiometric observations, including both China meteorological satellite FengYun-3 microwave payloads and Global Precipitation Mission (GPM) Microwave Imager (GMI), will be investigated in this study. The two spaceborne sensors were designed with dual polarized channels at 150 GHz and 166 GHz, respectively. The results presented in this study will provide information for the design of microwave radiometer on-board China second-generation global precipitation mission. [ABSTRACT FROM AUTHOR]

Anthropogenic greenhouse gases and aerosols are associated with climate change and human health risks. We used a global model to estimate both the climate and public health outcomes attributable to fossil fuel use, indicating the potential benefits of a phase out. We show that it can avoid an excess mortality rate of 3.61 (2.96–4.21) million per year attributable to ambient air pollution worldwide. This could be up to 5.55 (4.52–6.52) million per year by additionally controlling non-fossil anthropogenic sources. Globally, fossil fuel related emissions account for about 65% of the excess mortality, and 70% of the climate cooling by anthropogenic aerosols. The chemical influence of air pollution on aeolian dust contributes significantly to the aerosol cooling effect. Because aerosols affect the hydrologic cycle, removing the anthropogenic emissions in the model increases rainfall by 10–70% over densely populated regions in India and 10–30% over northern China, and by 10–40% over Central America, West Africa and the drought-prone Sahel, supporting water and food security. Since aerosols mask the anthropogenic rise in global temperature, removing fossil fuel generated particles liberates 0.51(+/-0.03)°C and all pollution particles 0.73(+/-0.03)°C warming, reaching around 2°C over North America and Northeast Asia. The steep temperature increase from removing aerosols can be moderated to about 0.36°(+/-0.06)°C by the simultaneous reduction of anthropogenic ozone and methane. In order to save millions of lives and restore aerosol-perturbed rainfall patterns, whilst limiting global warming to 2°C, a rapid phase-out of fossil fuel related emissions and major reductions of other anthropogenic sources are needed. [ABSTRACT FROM AUTHOR]

Ideally, model-data integration should take place throughout the course of an experiment, not just at the end. Model runs in advance of an experiment can help identify the most critical uncertainties and be used to help design measurement campaigns to address these uncertainties. Feedback of data to models during the experiment promotes careful archiving of data, identifies data gaps, aids the development of new hypotheses and helps target experimental work to maximise its scientific value. In this talk I will describe the model-data integration approach taken for a Free-Air CO2 Enrichment experiment at a mature broadleaf evergreen woodland growing on low-phosphorus soils (EucFACE). I will describe how the use of ecosystem models before and during the experiment is helping to provide new insights into the effects of CO2 enrichment on carbon, water and phosphorus cycling in this ecosystem, and outline our vision for how this new information can be implemented in models more broadly. [ABSTRACT FROM AUTHOR]

Climate change jeopardizes the future of hydropower across the world. Precipitation patterns evolve, glacier retreat affects sedimentation, and rising temperatures perturb both the water cycle and the energy-price seasonality. The energy sector also faces an energy turnaround. The growing penetration of intermittent wind and solar energy increases supply variability, thus price volatility. These trends raise concerns about the future profitability of traditional hydropower. This work quantifies these impacts with an integrated, transferable, and parsimonious model. It integrates a semi-distributed hydrological with hydropower management models to translate climate change and energy scenarios into future energy generation and revenue. We simulated nine future streamflow scenarios for an Italian and a Swiss case study. These inputs fueled a hydropower management model, which maximizes revenue accordingly to five Italian and twenty-eight Swiss electricity prices scenarios. The simulations couple both types of scenario for the period 2016-2045. This time horizon especially matters for current decisions in climate and energy policy. Results show that variations of climate regime adversely influence the hydroelectric production. Climate change will modify the seasonality of inflows and volumes that are exploitable for hydropower generation. However, smart hydropower management could mitigate revenue losses. This research represents a toolkit for dam operators and decision makers to assess future generation capacity in a warming climate. Key words: Climate Change, Hydropower, Electricity Market, Water-Energy Nexus, Modelling [ABSTRACT FROM AUTHOR]

North-Atlantic Cold-air outbreaks are weather events characterised by extensive fluxes of latent heat to the atmosphere. Understanding the water budget of these weather events is important for the weather impact in downstream coastal areas. We use here observations of the stable isotopic composition of water vapour and precipitation, expressed by the quantities dD, d18O, d17O and the secondary parameters d-excess and 17O-excess, to extract information about the origin and condensation history of water vapour evaporating during a period of cold-air outbreaks north of Iceland. During the campaign of the Iceland-Greenland Seas project (IGP) in March 2018, coinciding with the YOPP SOP1, water vapour isotope measurement instrumentation was deployed on the scientific vessel R/V Alliance, the research aircraft MASIN and a coastal location in Northern Iceland. With additional sampling of the snow deposited on land, a complete water cycle during continuous cold-air outbreak conditions could be sampled. The isotope composition of water vapor was sampled continuously during the cruise using a Picarro L2140i with a heated inlet system. In addition, manual collection of precipitation and water column samples from CTD were performed for isotope analysis. On the research aircraft, a modified Picarro L2130i sampled the water vapour isotope composition during 10 research flights. Calibration was performed both during flight and after landing. Continuous water vapour isotope measurements were performed at the nearby coastal location Husavik. Calibrated vapour isotope data from ship, aircraft, and station show good agreement during periods of intercomparison flights. A more complete precipitation sampling program along two transects east and west of Akureyri and measurements at Husavik further supplemented the water isotope sampling during IGP, providing a uniquely complete overview of the water cycle of cold-air outbreaks. Results from the comprehensive sampling campaigns provide insight into the spatial gradients and synoptic variability in the stable isotope composition during different weather events. In particular, our analyses show that evaporation conditions at the moisture sources are preserved to a variable degree in surface snow samples taken along topographic gradients. Initial modeling results also underline the importance of local topography for modifying the isotope signal deposited with precipitation. [ABSTRACT FROM AUTHOR]

An accurate characterization of the global hydrologic cycle is essential not only to study and forecast climate variations, but also for extreme event mitigation and agricultural planning. Since precipitation is the major driving force of the hydrological cycle, current and future satellite missions with a focus on precipitation are critical to estimate hydrological variables globally. Error estimates associated with satellite precipitation retrievals are crucial to allow inferences about the reliability of such products in their operational applications. However, evaluating satellite precipitation error characteristics is challenging because of the inherent temporal and spatial variability of precipitation, measurement errors, and sampling uncertainties, especially at fine temporal and spatial resolutions.This study proposes to use a stochastic error model – PUSH (Probability Uncertainty in Satellite Hydrology) – for estimating uncertainties associated with fine resolution satellite precipitation products. The framework is tested on the daily IMERG (Integrated Multi-satellitE Retrievals for GPM) infrared-only (IR) precipitation component using a satellite-based radar product (the Level-3 Dual-frequency Precipitation Radar, 3DPRD) as reference. PUSH decomposes the error into four components and employs different modeling approaches for each case: correct no-precipitation detection; missed precipitation; false alarm; hit bias. PUSH is calibrated globally over land for different climatological regions. The calibrated parameters are validated using an independent period to verify whether they can be applied to estimate uncertainties associated with future IR retrievals without degrading the model performance. The four error components are then investigated as a function of climate region to study their spatial variability. [ABSTRACT FROM AUTHOR]

Energy market is particularly sensitive to the renewable sources availability but their volatility makes them extremely difficult to use. For this reason, the skill to forecast these non-programmable fonts represents a crucial challenge that industrial companies have to face to improve their risk management. This work focuses on the analysis of the hydrological variables involved in melting processes of the snowpack over Alps whose glaciers act as natural reservoirs of water. To forecast the contribution from the snow/ice melting to the water cycle it is necessary to develop a proper model simulating a realistic response of snowpack to different external forcing.The ERA5 climate reanalyses are used to the scope. First, a preliminary analysis has been performed to better understand processes ruling the snow/ice melting over Italian Alps regions under different meteorological conditions in recent times. Therefore, specific areas of interest have been selected and studied paying particular attention to their position with respect to the reference hydropower plants and the consequent contribution to the basin water content. ERA5 reanalysis daily data have been averaged over a monthly time scale. The study will put the base for a future modelling application of the seasonal forecasts to the energy market contest within the Horizon 2020 SECLI-FIRM project. [ABSTRACT FROM AUTHOR]

Evapotranspiration, an important process representing a considerable amount of moisture lostto the atmosphere from the soil both by evaporation and by transpiration from the plantsgrowing thereon, is the link between water and energy cycles of the Earth, is the direct effectto local available precipitation. With the global warming, higher temperature is likely tolead to more evaporation, then lead to more precipitation. Tibetan-Plateau, as thethird pole in the world, is improved to be the amplifier of global change, where theclimate changes much sharper than the other regions. It is necessary to make clear theevapotranspiration change with the global warming over TP, and clarify the contribution oflocal evapotranspiration to precipitation. In our study, weather research and forecasting model(WRF) coupled with NOAH land surface model, being supplemented by MODISevapotranspiration remote sensing product, TRMM 3B42 V6 precipitation product andTRACE remote sensing product, is used to illustrate the water and energy cycle over TPconsidering the heterogeneities of elevation, landuse, and landscape, to quantify thecontribution of evapotranspiration to precipitation over entire TP, to explore theeffect of global warming on atmospheric environment over TP region. Based on thelong-term WRF simulation and remote sensing products, the trends of energy cycleelements including net radiation, latent heat flux, sensible heat flux, ground heat flux,and water cycle elements including evapotranspiration, rainfall, snowfall, runoff,soil moisture, ground water are analyzed, and then precipitation recycling over TPis disclosed. The results show that with global warming, land surface is feedingmore moisture to the atmosphere by increased evapotranspiration and a growingrecycling ratio, the contribution of evapotranspiration to local precipitation will bestrengthen. Evapotranspiration yielded by WRF model agrees well with MODISproduct, regional climate models can be considered a powerful complement to scarceobservational networks, especially for forecasting over complex terrain regions. [ABSTRACT FROM AUTHOR]

Arctic sea ice plays a critical role in modulating Earth's climate regime through its albedo effect, control on hydrological cycle and nutrient influx to oceans. The decline of sea ice has become more vigorous in Arctic Ocean, nevertheless, its driving mechanism is not fully elucidated. The halocline acts as a buffer layer separating Arctic sea ice and warm water mass, namely Atlantic Layer, which originated from North Atlantic Ocean. The halocline slows down heat transfer from warm Atlantic Layer to the sea ice, and thus, hampers sea ice retreat. Research proposed that the fluctuation of halocline thickness in the Arctic could be a plausible parameter limiting sea ice development. We, therefore, aim to evaluate the halocline's depth and its impact on sea ice cover in the last climatic cycle. By measuring Mg/Ca of ostracods' shells from sediment cores retrieved at different water depths (434m to 741m) in the Chukchi Plateau of Western Arctic Ocean, we aim to reconstruct the halocline thickness. In all cores we observed comparable water temperature in MIS1 and MIS3, which had been fluctuating between 0°C and 1.5°C, suggesting the presence of warm Atlantic Layer up to 434m. Therefore, it indicated a thinner and shallower halocline in MIS3 than results from previous research. Arctic sea ice decline in last climatic cycle might possibly be explained by the shift of halocline to a shallower depth. [ABSTRACT FROM AUTHOR]

Through time, Earth's climate state has transitioned between non-glacial, glacial, and pan-glacial (Snowball Earth) regimes. A major unsolved question is: what sets Earth's climate state on these million-year timescales? While shifts between prolonged non-glacial and glacial intervals are widely considered to result from plate tectonic processes, the primary driver remains unclear. On geological time-scales, CO2 is emitted primarily by volcanism and consumed primarily by the chemical weathering of silicate rocks. Prolonged imbalances between sources and sinks would catastrophically manifest in either the onset of a Snowball Earth or a runaway greenhouse. The relative clemency of Phanerozoic climate requires that CO2 sinks scale with sources, which can be explained through the silicate weathering feedback where elevated CO2 leads to higher temperatures and invigorated hydrological cycling that enhances chemical weathering and vice versa. Given that CO2 sources must equal sinks on long timescales, what sets steady-state CO2 levels on Earth at a given time? The concept of global weatherability, the product of variables such as lithology, tectonic uplift rates, and paleolatitude, which are set by evolving plate tectonic boundary conditions, is a useful framework to address these questions. On a more weatherable planet, the CO2 concentration needed for the sink to equal the source is lower than on a less weatherable planet where CO2 increases until high enough levels are reached for the chemical weathering flux to be sufficiently large. In this contribution, we evaluate long-term changes in paleogeography and mountain-building and their connections to Phanerozoic climate. We seek to test the hypothesis that ocean basin closure, arc-continent collision and ophiolite exhumation exert a major control on Earth's climate state by enhancing global weatherability. Using paleogeographic models, we reconstruct the past positions of ophiolite-bearing sutures from a newly-developed database. We find that when extensive arc-continent collisions have occurred in the tropics, the Earth has experienced a glacial climate, and otherwise the Earth has been in a non-glacial climate state. We interpret plate tectonic driven changes in rock type and topography in the tropics to be the most significant control on Earth's long-term climate state. [ABSTRACT FROM AUTHOR]

Soil deep percolation is an important link of terrestrial hydrological cycle, and the amount of soil deep percolation is closely related to the amount of soil water storage. In this study, the real-time monitoring of soil deep percolation of typical mobile dunes in Maowusu sandy land was carried out by using the soil deep percolation recorder. Combined with the analysis of soil water storage, the following conclusions are drawn: (1) During the monitoring period, the precipitation in 2016 were 574.7 mm, and the variation ranges of water storage in the three layers of 0-50 cm, 50-100 cm and 100-200 cm were 13.78-42.47 mm, 14.46-26.43 mm and 38.52-89.46 mm, respectively, with the coefficients of variation being 0.21, 0.13 and 0.17; the precipitation in 2017 was 297.8 mm, and the variation ranges of water storage in the three layers were 17.58-39.51 mm, 14.33-22.79 mm and 40.95-51.16 mm, with the coefficients of variation being 0.17, 0.11 and 0.06, respectively, which were all smaller than 2016. The soil deep percolation at 50 cm, 100 cm and 200 cm in 2016 was 381.8 mm, 341.6 mm and 270.2 mm, which were 4.53, 5.53 and 5.22 times of the same period in 2017, respectively. (2) There was a significant correlation between the amount of water storage in the upper soil and the amount of soil deep percolation on the next day (p < 0.01), which reflected the lagging phenomenon of percolation. (3)The relationship between the water storage of 50-100 cm layer and the percolation at 100 cm, and between the water storage of 100-200 cm layer and the percolation at 200 cm accorded with the logistic equation of growth model, and the fitting effect was preferably. The R2 values were 0.4677 and 0.8986, respectively. The characteristics and relationships above were of great significance for estimating the soil deep percolation of sandy soil under certain precipitation conditions. [ABSTRACT FROM AUTHOR]

Large-scale Hydrological Models (LHMs) are increasingly used in studies concerning the water cycle at synoptic, continent, and global scales. These models are not constrained to reproduce hydrological processes and streamflow at the local scale, i.e. the scale at which water resources are managed.In the present study, we evaluated suitable modifications of the Community Land Model v3.5 (CLM3.5), which improve streamflow reproduction in a relatively large Alpine catchment: the Adige river basin, south-eastern Alps with a drainage area of about 10500 km2 at the Trento gauging station. In particular, we added to CLM3.5 a simple module dealing with deep infiltration to aquifers and return flow, and replaced the grid based routing scheme with the multi-scale grid independent scheme embedded in the HYPERstreamHS hydrological model. The performance of a calibrated run of HYPERstreamHS stand-alone model in reproducing observed streamflow at the Trento gauging station was also evaluated to provide a benchmark for assessing the effectiveness of the introduced parameterizations of deep infiltration, return flow and streamflow routing. Note, all simulation runs were informed by the same meteorological forcing.Runoff computed by CLM3.5 with the HYPERstream routing scheme improved the performances of the Nash Sutcliffe Efficiency (NSE) from -0.05 (uncalibrated CLM3.5 run) to 0.15. Furthermore, results indicate that, at least in the case of the Alpine watershed considered in this study, low NSE values are due to an underestimation of the water recharging deep aquifers and not re-entering the river network in CLM3.5. In addition, simulations using HYPERstreamHS informed by actual evapotranspiration outputs as provided by CLM3.5 showed a good agreement with observations (NSE = 0.61), which is very close to the performance obtained with the stand-alone run of HYPERstreamHS (NSE=0.65), thus suggesting that the land surface energy and mass balance is correctly simulated in CLM3.5 model also at the local scale.Results of this study suggest that a significant improvement of the performance of CLM3.5 in reproducing observed streamflow time series at the local scale may be achieved by replacing the grid based routing scheme with a more accurate scale-independent routing scheme and adding a simple parametrization of deep infiltration, with the latter producing the most significant improvement. [ABSTRACT FROM AUTHOR]

Rainfall production is a fundamental process within the Earth's hydrological cycle because it represents both a principal forcing term in surface water budgets, and its energetics corollary, latent heating, is the principal source of atmospheric diabatic heating. Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water. The properties of the vertical distribution of latent heat release modulate large-scale meridional and zonal circulations within the Tropics - as well as modify the energetic efficiencies of mid-latitude weather systems. This paper highlights the retrieval of latent heat release from satellite measurements generated by the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM) satellite observatory, which were launched in November 1997 and February 2014, respectively. Both TRMM and GPM measurements have been providing an accurate four-dimensional account of rainfall over the global Tropics and mid-latitudes: information that can be used to estimate the space-time structure of latent heating.Two sets of latent heating retrieval algorithm methodologies (Goddard Convective-Stratiform or CSH, and Japan Spectral Latent Heating or SLH) have been developed to estimate latent heating based on rain rate profile retrievals obtained from TRMM and GPM measurements. The differences and similarities between the CSH and SLH algorithm design will be presented. The presentation then will provide the results of LH structures derived from the TRMM and GPM. At the end of presentation, the further research on latent heating retrieval from satellites will be discussed. [ABSTRACT FROM AUTHOR]

Observing and understanding processes of the daily water cycle (DWC) over land with a high spatial resolution is one of the outstanding grand challenges in Earth Observation (EO). This challenge has been taken up by the G-Glass mission, which is a geosynchronous C-band radar satellite that was recently selected by ESA as one of the candidate mission for its 10th Earth Explorer. Among other variables, G-Class will observe soil moisture and precipitation, which are key to understand the DWC. Both variables can be retrieved from spaceborne radar observations in a sequential manner: Firstly, soil moisture can be estimated by inverting a backscatter model that describes the interaction of the microwave pulses with the vegetation and soil surface. Secondly, precipitation can be derived from the soil moisture data by inverting a soil water balance model. Research has already demonstrated the feasibility of this approach, and a number of operational services do exist (for soil moisture) or are about to be introduced soon (for precipitation). However, existing services do not properly resolve the DWC as they rest on polar-orbiting radar satellites that capture soil moisture at best twice a day at their ascending and descending passes respectively. Even though daily rainfall can be estimated from such data, estimates remain rather noisy. To more densely sample soil moisture across one day, and to reduce the noise in the daily rainfall estimates it is essential to collect several backscatter measurements per day. This may be achieved, as proposed by G-Class, by a geosynchronous satellite that observes the same land surface areas every few hours (1-3 hours). In this presentation the current planning for C-Glass will be reviewed. Furthermore, we will discuss expected strengths and limitations of G-Class based on results obtained with METOP ASCAT and Sentinel-1 that measure, like G-Class, backscatter at C-band. [ABSTRACT FROM AUTHOR]

Since 2002, the GRACE mission (Gravity Recovery and Climate Experiment) – a joint mission by NASA and DLR – has observed the terrestrial water storage and has improved our knowledge of the global water cycle significantly over the last 16 years. GRACE-derived information has been used to improve hydrological models in terms of model calibration and data assimilation. However, localized small-scale mass variations, such as caused by human-controlled reservoirs, that are spatially below the GRACE resolution but large enough in magnitude, can have a strong influence on the mass change signal. Even though GRACE can "see" these mass changes, they do not necessarily appear exactly at the location of their origin and with the correct magnitude. Thus they can distort the water storage estimate for neighboring areas or the average over a river basin. In the newly established DFG Research Unit GlobalCDA, GRACE data (among various other geodetic and remote sensing data sets) shall be used to improve a global hydrological model via calibration and data assimilation. Prior to data assimilation, however, the GRACE signal has to be cleaned from these localized features (e.g. reservoir effects), which are not properly represented in the model, in order to make GRACE water storage estimates consistent with the model output.In this presentation, we will discuss methods to quantify and remove the effect of the concentrated mass signals from the GRACE data based on a forward modeling of the expected small-scale mass features using altimetry and remote sensing information. Furthermore, we will discuss possibilities to include a comprehensive dataset of several types of surface water bodies (e.g. natural lakes, rivers) to estimate their combined influence on the GRACE signal on a basin-wide scale. [ABSTRACT FROM AUTHOR]

In general, drought monitoring is the most commonly evaluated by drought index. The Palmer Drought Severity Index (PDSI) was created by Palmer (1965) with the intent to measure the cumulative effect in soil moisture supply and demand at the surface. However, this index is often lack of applicability in extremely dry area, and its calculation and application are very complex as well. So, this paper evaluates the spatial scope and temporal regularity of drought over eurasian continent at global warming from four parameters : precipitation, runoff, evaporation and soil moisture. As the latest generation of reanalysis data, ERA5 has been widely used in the field of remote sensing, because it has more atmospheric variable and finer resolution. Based on ERA5 reanalysis datasets, regional drought conditions are effectively assessed by calculating Standardized precipitation index (SPI) and the anomaly percentage between 2000-2017.On the other hand, due to the impact of sea surface temperature (SST) on the drought, such as the SST forcings during 1950–2000 increase the summer land-ocean temperature contrast and thus enhance the drought. Therefore, we analyses SST and the height of the potential difference in recent years. Results are as follows: (1) Regional runoff has decreased every year since 2010, which could increase the frequency of drought. Except for parts of West Asia, the annual variation of precipitation in the other places are not significant, but the SPI is opposite. The next, soil moisture and precipitation are consistent in most regions, and the abnormal percentage is stable within 20%. However, the amount of evaporation increased significantly in 2017, which may be caused by global warming or El Niño. (2) At the same time, SST anomalous descending and ascending motion occurs over the northern Indian Ocean and South Pacific Ocean areas,while the SPI is anmalous. This is consistent with the above-mentioned drought conditions to some extent. But the specific contact between SST and drought formation still require further study.Overall, the frequency of droughts may not increase in the near future, but if they do, they may occur faster and more dramatically.Index Terms—Drought assessment; ERA5; Global warming. [ABSTRACT FROM AUTHOR]

Global hydrological models (GHMs) have been widely used in scientific studies to describe the hydrological cycle at large scale. Many improvements have been made to these models, e.g., to include human influences, such as reservoir operations, water uses and land cover changes. Given these enhancements, the question is now how well these models can reflect trends and drought characteristics found in streamflow observations of relatively small catchments, where flow might be altered by different (local) human influences.To answer this question, this study compares discharge data from different GHMs with observations in 189 gauging stations around England and Wales. A common characteristic of the considered catchments is their relatively small size (10-10000 km2) and part of the challenge consists in studying the ability of the models to describe hydrological conditions and human influences at such small scale. The selected catchments consist of a mix of catchments with near-natural flow as well as catchments with different human influences, such as groundwater abstraction and reservoir management. For all catchments, discharges trends and drought event characteristics have been determined from both observed and modelled time series and outcomes have been compared.Preliminary results show that these course resolution GHMs have larger catchments areas and, therefore, overestimate discharge. When corrected for the area, the agreement between observed and modelled discharge still varies widely per catchment and per model and there does not seem to be a clear spatial performances pattern. The identified trends and drought characteristics also vary among GHMs and from GHMs to observations. Most models, however, seem to reproduce the observed seasonal trends (negative in winter and positive in summer) which might be more related to trends in forcing data, then to trends in human activities. The influence of human activities on drought characteristics is not as clear, with only some effects of groundwater abstraction emerging in the most affected regions. Part of the problem with this type of study is that, for both observed and modelled data, there are no time series data available on the amount of water abstracted or stored in a basin or grid cell. Additionally, differences in representative spatial scale of GHMs and catchment data has a strong impact on the time series comparison. Our large-sample study aimed to overcome these factors by using a large number of catchments with at least a qualitative information on the type of human influences, but further analysis should be carried out both to deepen the knowledge about human influences on the hydrological cycle and to connect and bring together larger and smaller scale. [ABSTRACT FROM AUTHOR]

This study presents the first insights into the intensifying impact of global warming on extreme hydrological shifts between wet and dry conditions at the sub-seasonal to seasonal scale. For instance, the flood in England during the summer of 2007 was followed by heavy drought conditions, and a switch took place in the recent past from extreme drought to severe flooding in California. Most recently, the 2018 flood to drought transition in Japan brought on one of the most intense heatwaves the country has ever faced. These are just a few real-world examples. Considering the interconnected nature of the processes governing the increases in wet and dry events, we introduce a new index called 'Event to event variability (E2E)' as a proxy of the hydrological cycle, taking the aforementioned shifts in wet to dry (or dry to wet) transition into account. Based on multi-model large ensemble climate simulations, we assessed the impact of half a degree of additional warming from 1.5°C to 2°C for the global mean temperature, reflecting the warming targets of the Paris agreement of 2015 that were adopted at the 21st Conference of the Parties (COP) of the United Nations Framework Convention on Climate Change (UNFCC). Our results show that for an additional 0.5°C warming, mean intensification of the wet-dry (or dry-wet) transition will be significant on a global scale. The E2E index was further utilized to investigate the extreme conditions of said intensification, which showed extremes will increase 10 times compared to the mean state intensification. We found that event-to-event variability increases with warming for Western North America, Japan, and the UK, exhibiting intensification in both wet and dry conditions, which is potentially attributable to the increased occurrence of the aforementioned extreme events. We believe that our study will provide a new perspective into hydroclimatic stress under the future climate, in particular, for the additional 0.5°C warming and the importance of adhering to the Paris Agreement. [ABSTRACT FROM AUTHOR]

Precipitation isotopes preserve information about the histories from evaporation in the sourceregions, moisture transport, and to precipitation events, and hence was used in revealing thedynamics of regional hydrological cycle and paleoclimate rebuilding. In the monsoon region,quite a few studies emphasized the strong inverse impact of convective activity onprecipitation isotope ratio, envoke the debate about the interpretation of these ice core recordsas temperature proxies on the Tibetan Plateaus. Recent study also showed statistically theinverse influence of the proportions of stratiform to convective precipitation on water isotopein tropical and mid-latitude regions, highlighting the important role of precipitation type onisotope hydrological cycle. The influence mechanism on seasonal and interannual scaleremain highly uncertain and poorly understood, which is crucial for the utilization ofisotopes in paleoclimate studies. To further address the influence of precipitationpattern, in particular the large regional cloud cover, on water isotopes, here we use adecade of precipitation isotopes from southern Tibetan Plateau (TP) to explore thethe close relationship with both the large scale cloud cover and local climate. Wecalculated the correlation between local precipitation δ18O with different levelcloud data archived in ECMWF. Sensitive zone is identified in the northern Indiasubcontinent to the seasonal precipitation isotope in southern TP, and high negativecorrelation with total cloud cover (TCC) and high cloud cover, indicates high-levelconvection in the upper stream of moisture transport is among some of the importantfactors in controlling the seasonal precipitation isotope in southern TP. However, thecorrelation with local cloud cover in the sampling basin is less significant. Themechanism underlying with the finding is that strong convection activity in themoisture source region and on the route significantly depletes heavy isotopes in thevapor, and subsequently, produces much decreased precipitation δ18O values inthe study region. On the interannual scale, there are robust negative precipitationδ18O-TCC correlations, large positive correlations between TCC and SouthernOscillation Index over the Arabian Sea, where is different from the most significantcorrelative region of the seasonal variation. It indicates that the processes influencethe seasonal variations of the precipitation isotopes is different from those whichare important for the interannualy means. The interannual to decadal interannualprecipitation δ18O record monsoon intensity and upstream rainout resulting from ENSO.The specific study site is located in the Yamdruk-tso basin at an elevation over4400m, and thus the results from this elevation are of more significance for the higherelevation ice core records in that region. Moreover, these findings throw light on theinterpretation of paleoisotope records obtained from the India Summer Monsoonregion. KeywordsPrecipitation isotopes; Cloud cover; Convective activity; Local and regionalcontrol; Yamdruk-tso basin; Southern Tibetan Plateau [ABSTRACT FROM AUTHOR]

Population growth, urbanisation and environmental change are leading to increased water stress affecting many millions of people worldwide. Attempts to mitigate the problem require a detailed understanding of the feedbacks between humans and the natural environment. Isolating the role humans play in the water cycle, however, is challenging, requiring knowledge of human water use behaviour and the underlying hydrological processes.Here, we elucidate farmer irrigation decision making using a bottom-up sociohydrological modelling framework which is informed by fieldwork carried out in north India (O'Keeffe et al., 2018). The modelling framework conceptualises and proceduralises observed farmer irrigation practices in the Indo-Gangetic Plain, placing human behaviour at its core while highlighting impacts and interactions between society and the natural environment. Though this approach, we isolate the effects of human behaviour and allow the impact of anthroprogenic water use on the hydrological cycle to be quantified. We apply the model to the Gandak river basin; a tributary of the Ganges river located in Bihar state in northern India which is representative of the social and environmental conditions found throughout the region. By simulating the relationships between the water users, irrigation officials and agricultural practices, we highlight the importance of directly including water user behaviour in policy making and operational tools to achieve water and livelihood security as well as improving our understanding of the hydrological cycle.References:O'Keeffe, Jimmy, Simon Moulds, Emma Bergin, Nicholas Brozovic, Ana Mijic, and Wouter Buytaert. 2018. "Including Farmer Irrigation Behavior in a Socio‐hydrological Modelling Framework with Application in North India." Water Resources Research, 1–18. doi:10.1029/2018WR023038. [ABSTRACT FROM AUTHOR]

Actual evapotranspiration (ETА) is a fundamental variable of the hydrological cycle playing a principal role on surface water balance. Detailed ETА estimation data is important subject for numerous applications including irrigation management, water resources planning and environmental studies. At the plot scale ETА can be accurately determined from detailed ground observations but at regional (even field) scale, numerous time-consuming and expensive installations would be required. In the last few decades, earth observation technology become provide spatially distributed cost-effective information for ETА maps production at regional scale. The increased availability of observed data for long monitoring periods and of advanced techniques for the spatiotemporal analysis of acquired information allows to describe trends in evapotranspiration behavior and find the reason of it. In this study the MODerate Resolution Imaging Spectroradiometer (MODIS) ETА product data (8 days temporal resolution for the period of 2000-2017) were integrated and processed in GIS environment in order to obtain the final goal of finding spatiotemporal distribution of the ETА for the territory of two study sites with high agricultural activities. Methodology used to assess spatial distribution of ETА trend over study regions for warm year periods (spring, summer and autumn) is consisted on: (1) building gridded time series datasets; (2) time series testing for stationary; (3) trend calculation by modified Mann-Kendall test for non-stationary time series; (4) analyzing of spatial patterns distribution. Obtained results show evidence of strong correlation in ETА behavior and agriculture farming changes (crop water demand). This means that losses due to evapotranspiration in agriculture can be handled in a way allowing to assure the best conditions for agricultural needs of the region.Authors express their gratitude to the Russian Foundation for Basic Research for providing financial support of the project 16-05-01097. [ABSTRACT FROM AUTHOR]

Human perturbation of the nitrogen cycle represents one of the major actions that allowed thehuman population to expand and grow in the twentieth century. Nowadays, the environmentalconsequences of excessive reactive nitrogen include atmospheric pollution, nutritionunbalance in aquatic and terrestrial ecosystems, surface and groundwater qualitydegradation. Nitrogen can enter the water cycle through atmospheric depositions on ground and watersurfaces, leakages from point and diffuse sources (i.e., sewage treatment plants orsewage systems, fertilizer and manure applications), and erosion processes affectingnitrogen rich soils. However, integrating all nitrogen forms, processes and scales isstill a major challenge for the understanding and the management of the nitrogencycle. This study aims to evaluate the impacts of atmospheric pollution on terrestrial andgroundwater ecosystems, focusing on nitrogen compounds. A monitoring experiment was setup to collect wet atmospheric depositions in a human impacted area with multipleland uses, representing different emission sources (i.e., extended urban areas withresidential buildings and industrial activities, high traffic roads and agriculturalactivities). Wet deposition is measured at 17 sites, homogeneously distributed in the westernsector of Lombardy Region (northern Italy), in the surroundings of Milan. Rainfallcollection started in February 2017. By the end of 2018, 15 precipitation events weremonitored and 144 rainwater samples were collected, involving an average of 10 sitesper event. After collection, samples were analysed for pH, electric conductivity,ammonium, nitrate, nitrite, major cations (calcium, magnesium, sodium, potassium), andmajor anions (sulphate, chloride, fluoride). Rainfall chemistry was compared toatmospheric pollution, derived from air quality data from ground-based stations andpollutant emissions data provided by the Regional Environmental Agency (ARPALombardia). Results show a direct relationship between high levels of air pollutants (e.g., NO2, SO2,NH3) and relatively high contaminant concentrations (e.g., NO3−, SO42−, NH4+) inrainwater samples. Consequently, rainfalls sampled in autumn-winter or during thefertilisation period (April-May) show higher contaminant concentrations respect to thosesampled in spring-summer or before the fertilisation period. In addition, the chemicalcomposition of rainfall samples reflects local meteorological conditions and local emissionsources. In fact, samples collected in urban or agricultural areas show higher concentrationsof specific chemical species (e.g., Ca2+, NO3−, NH4+) in comparison to those collected inrural areas or close to natural environments (i.e., Alps and Como Lake). Such resultsallowed estimating wet nitrogen depositions, as nitrate and ammonia, in the studyarea. The average concentrations of nitrate and ammonia in precipitation during themonitoring period were 5 mg L−1 and 2.5 mg L−1, respectively. Consequently, given anaverage annual precipitation of about 800 mm for the period 2016-2018, a wetdeposition of inorganic nitrogen equal to 9 kg (NO3−-N) ha−1 yr−1 and 12.4 kg(NH4+-N) ha−1 yr−1 was estimated. As leaching of nitrogen compounds from soilsgenerally increases at nitrogen deposition rates higher than 10 kg ha−1 yr−1, this studysuggests that the nitrogen atmospheric input to soils should not be neglected whenevaluating the impacts of nitrogen sources to terrestrial and aquatic ecosystems. [ABSTRACT FROM AUTHOR]

We are faced with negative changes concerning social and the natural environment induced the degradation of permafrost, which is related to recent global warming. Thawing permafrost affects the hydrological cycle, geomorphological processes, as well as vegetation changes. Mongolia territory is by about 63 % within permafrost zone. Therefore, it is important to understand the dynamic of the process and controlling factors responsible for the permafrost degradation. We studied two peatlands Khar Zurkhnii Khukh Nuur in the Khentii mountain range (NE Mongolia). This part of Mongolia is characterized by the occurrence of the forest-steppe mosaic in the area of discontinuous permafrost. We aimed to reconstruct dependence between vegetation composition, fire regime shift and timing of permafrost degradation during the last 1600 years from two peat archive. For this purpose, we worked on peat archive and used multi-proxy analysis (pollen, plant macrofossils, testate amoebae, Cladocera, macro-charcoal, and geochemistry). Two profiles: 36-cm (KH-1) and 55-cm (KH-2) have been extracted from two nearby peatlands, which are only 1 km away. Chronology of the KH-1 core was based on 6 AMS 14C dates, 137Cs, and 210Pb analyses, while the second core KH-2 was based on 11 AMS 14C dates. Respectively, the core KH-1 covers the last 250 years and the core KH-2 covers the last 1600 years. Our first results indicate a strong relationship between degradation permafrost, droughts, vegetation forest-steppe mosaic composition and fire regime shifts, which caused intensified erosion in the catchment. Palaeoecological and geochemical data allowed tracing the dynamics of degradation permafrost and impact of fire regime shifts on the ecosystems, both triggered by recent and past climate changes. The research was funded by the National Science Centre (Poland) – grants 2017/01/X/ST10/01216 [ABSTRACT FROM AUTHOR]

The Arctic water cycle is undergoing pronounced change in the atmosphere, hydrosphere, and cryosphere. Reduced albedo due to declining sea ice extent is amplifying Arctic temperatures and atmospheric humidity, leading to complex seasonal patterns of synoptic climate, evaporation and precipitation. To better understand, quantify, and monitor these changes, in December 2017 we installed a new Picarro continuous water vapor analyzer at the Finnish Meteorological Institute's research station in Pallas-Yllästunturi National Park, 170 km north of the Arctic Circle. Here, we pair real-time (1 second) water vapor isotope measurements (δ18O, δ2H) with a suite of meteorological parameters − including air temperature, relative humidity, solar flux, wind speed and direction – as well as a Lagrangian moisture source diagnostic for isotopic fingerprinting of atmospheric transport pathways. Pallas vapor compositions range between -20 to -38 ‰ for δ18O and -140 to -300 ‰ for δ2H, and exhibit pronounced diurnal, weekly, monthly and seasonal fluctuations. We use the deuterium excess parameter (d-excess; δ2H−8.δ18O) to partition the water vapor flux from different moisture source regions across the Arctic and sub-Arctic. Of note is the observation that d-excess values oscillate substantially (> ±20 ‰) and rapidly in response to shifting synoptic conditions and divergent storm tracks; for example, switching from vapor derived in the eastern Barents and Kara Seas to vapor from the North Atlantic or Greenland Sea, and these nuances are further explored in relation to sea ice coverage or lack thereof. Delineating these changes at such fine definition using our land-based system are key to reconciling how a changing Arctic system with reduced sea ice and divergent ocean temperatures are altering typical patterns of synoptic weather, for example the remarkable winter and spring snow conditions that blanketed much of northern Europe and North America in 2018. [ABSTRACT FROM AUTHOR]

The land and atmosphere are interlocked by coupled hydrologic and energy cycles that are a major part ofthe Earth's climate system, but the feedback from soil moisture to precipitation via the return path throughevapotranspiration (latent heat flux) is weak. Nevertheless, a few studies have addressed the crucial role of soilmoisture feedbacks in European droughts, while others assessed the effect of dry soils in amplifying and prolonghot temperatures associated with heat waves in Europe. Surface moisture deficits are a relevant factor for theoccurrence of hot extremes in many areas of the world, then the effects of soil moisture-temperature couplingare geographically more widespread than commonly assumed. This suggests that hot day predictions could besubstantially improved in operational forecasts with the aid of soil moisture initialization.In this work, several sensitivity experiments were performed to assess the role of key climate componentson Mediterranean weather at the seasonal time-scale. Specifically, six experiments have been designed to evaluatethe impact of soil moisture on the summer season. In a region often hit by summer heat waves, the main goal isthe assessment of the land-atmosphere response to heat waves hitting a pre-existing a) dry soil or b) wet soil. Todo that, land and atmosphere have alternatively been coupled and uncoupled.When hot air advections hit a wet soil, shorter and less intense (i.e. characterized by lower temperatures)heat waves are recorded only if land and atmosphere are uncoupled. Otherwise, hot air rapidly dries the terrainoff, inhibiting the mitigation effect of the pre-existing wetness, and heat waves are more severe. Instead, enhancedand prolonged suppression of precipitation, recursively triggering new heat waves, is remarkable when hot airencounters a pre-existing dry soil, majorly when land and atmosphere are coupled. [ABSTRACT FROM AUTHOR]

In agricultural areas where water is a limited resource, farmers and managers have been building small water reservoirs, sometimes in large numbers. Small reservoirs are infrastructures mainly used to store runoff water during the wet season to support irrigation water demand during the dry season. However, the development of small reservoirs in a catchment can have a significant cumulative effect on the hydrological cycle and on the stream flow (Habets et al., 2018). The cumulative effect is complex and still difficult to understand at present. The cumulative effect is a result of interactions between (i) agricultural activities, which determine the crop water demand and control the hydrological processes that generate the water resource, (ii) reservoir management, which involves number and location of reservoirs and decisions of reservoir water uses, and (iii) the hydrological functioning of the catchment, which controls the filling of reservoirs.Numerical modelling is an interesting approach to quantify cumulative effect and understand the interactions that underlies them, provided that it is possible to benefit from a model that explicitly takes into account a wide spectrum of hydrological and agronomic processes, including reservoirs, in a spatially distributed manner and at time steps compatible with hydrological and agronomic processes. Some models have already been used to simulate a watershed with reservoirs, but none of them fulfilled all the characteristics mentioned above. We therefore have developed such a new and original spatially distributed model, called DAHM-Reservoir, using the OpenFLUID platform (Fabre et al., 2019). This model explicitly represents the main elements of an agricultural catchment (agricultural fields, non-agricultural plots, stream reaches, reservoirs, soils, groundwater) and the water fluxes between them, whether these fluxes are hydrological or anthropogenic. The main processes coupled in DAHM-Reservoir are those involved in the hydrological functioning of catchment and reservoirs (infiltration, evaporation, transpiration, runoff, groundwater flow, river transfer, etc.), in the growth and yield of crops (tillage, irrigation, seeding and harvesting), and farmer decisions related to crop and water management (water withdrawal decisions based on farmer's demand for crop irrigation, downstream water restitution according to regulation) (Therond and Villerd, 2018). DAHM-Reservoir reuses the representation of elementary processes already implemented in other models (MAELIA, SWAT, MHYDAS). The interests of this model will be discussed based on an application to a catchment in southwestern France.Fabre, J.-C., Thöni A., and Crevoisier D. (2019). "OpenFLUID." Documentation. OpenFLUID: Modelling Fluxes in Landscapes. https://www.openfluid-project.org/.Habets, F., Molénat J., Carluer N., Douez O., and Leenhardt D. (2018). "The Cumulative Impacts of Small Reservoirs on Hydrology: A Review." Science of The Total Environment vol.643: p.850–67. https://doi.org/10.1016/j.scitotenv.2018.06.188.Therond, O. and Villerd J. (2018). "Plateforme Maelia." Documentation. Maelia: Multi-Agents for EnvironmentaL norms Impact Assessment. http://maelia-platform.inra.fr/. [ABSTRACT FROM AUTHOR]

Forests in the Amazon and Congo supply substantial amounts of evaporation for their own rainfall, through i.e. moisture recycling. However, large-scale deforestation reduces evaporation and thus dampens the water cycle, while climate change is projected to increase drought risks. In view of this dual pressure, we aim to understand the role of Amazon and Congo rainforests for maintaining their own resilience through moisture recycling during the driest periods. We use 34 years of reanalysis and synthesis precipitation data with the moisture tracking model WAM-2layers to (1) analyse how forest moisture recycling deviate from mean annual during the dry seasons and dry years, and (2) identify the extent to which moisture recycling deviations can be explained by deviations in evaporation and wind respectively. We find that the relative importance of the forests as moisture suppliers for their own rainfall increases during dry seasons. Dry years, i.e., years with low rainfall or water availability, further amplify dry season moisture recycling – and the forests' rainfall self-reliance – in both regions. We further introduce a new metric – the correspondence ratio between deviations in dry period precipitation moisture source and evaporation – that identifies the regions, in which evaporation anomalies most correspond to, and presumably are most likely to explain the dry period anomalies of forest precipitation moisture source. The dry period intensification of moisture recycling implies an increased dependence of forest rainfall on forest evaporation, and thus an increased sensitivity to deforestation, during times with limited water availability. Lastly, by assuming that the forest-rainfall relationship in space holds for the relationship over time, we find that the risk for a forest-savanna transition is elevated in both Amazon and Congo if mean dry season precipitation would fall to dry year levels. We conclude that dry period intensification of moisture recycling constitute an important hydrometeorological phenomenon to consider for understanding the joint impact of deforestation and climate change on forest resilience. [ABSTRACT FROM AUTHOR]

The New Madrid Seismic Zone is an active seismic zone in the Midwestern United States. While in most parts of the continental US seismic activity increased in the last decade largely due to wastewater injections in context with oil and gas production, for the New Madrid Seismic Zone seismicity has been suggested to be related to hydrological loading. Hydrological extreme events such as drought and flooding change the surface loading and can influence the seismicity rates by perturbing the subsurface stress. Besides affecting seismicity rates, loading and unloading of the Earth due to the hydrological seasonal cycle displaces the ground surface and changes the gravitational potential. For testing this hypothesis, the correlation between vertical displacement, seismicity and hydrological mass change needs to be quantified. In our study, crustal deformations are measured using continuously operating GPS sites in the New Madrid seismic Zone. GRACE data and hydrological models provide useful information about hydrological mass changes. Here, we discuss our GPS processing in the New Madrid Seismic Zone and our analysis of position time series.GPS raw data are processed for more than 30 sites in the New Madrid Seismic Zones. The raw data are available from public sources (CORS, UNAVCO, SOPAC) with continuous observations up to 20 years. We focus on the period between 2002-2017 that is also covered by the GRACE mission. Daily point position time series are processed, applying the same background geophysical models (solid and ocean Earth tide, atmospheric tidal and non-tidal loading, non-tidal ocean loading) as used in GRACE Level-2 processing. GPS time series resulting from different scientific software can differ in repeatability and show systematic periodic differences. Therefore we process position time series with the Bernese Software and the GipsyX Software and compare the results. Precise Point Positioning and the network strategy are applied. [ABSTRACT FROM AUTHOR]

The Mesozoic Era was punctuated by periods of rapid environmental change, known asOceanic Anoxic Events (OAEs), during which a rapid rise in temperature was accompaniedby an accelerated hydrological cycle, enhanced continental weathering, increasednutrient input to the oceans, intensified upwelling, increased organic productivity andexpansion of marine anoxia/euxinia, all documented through a range of geochemicalproxies. However, a major issue in the study of OAEs is the absence of good temporal constraintson these proxy records, as timescales can be hard to construct over sections whereenvironmental perturbations have resulted in rapidly changing lithologies and, potentially,sedimentation rates. The use of extraterrestrial 3He concentration as a proxy for sedimentation rate in marinesediments allows the construction of high-resolution timescales. This methodology isparticularly suited for 'difficult&#x2019; sections, such as those recording OAEs, because aninstantaneous sedimentation rate is determined for each sample measured; timescales cantherefore be constructed over sections with rapid fluctuations in lithology where the cyclicalsignals required for cyclostratigraphic timescales may be difficult to identify. The resolutionof such a timescale is also therefore theoretically limited only by sampling density (and themixing effects of any bioturbation). We use this technique to construct a high-resolution timescale over the Bonarelli Level, a∼1 m-thick stratigraphic unit of millimetre-laminated organic-rich black shale andradiolarian sands which is the expression of the Cenomanian–Turonian OAE 2 in centralItaly, and represents a historically important and well-studied section. In order to measurehelium in the extremely organic carbon rich shales of the Bonarelli Level (&#x003E; 30% TOClocally in some horizons), we build on previously established techniques and expand therange of lithologies to which this method has been applied to include organic-rich blackshales. Using our 3HeET timescale, we are able to provide an estimate for the timespanned by the Bonarelli Level, explore the possibility of hiatuses and condensedsedimentation at its top and base and examine the depositional rates of differentlithologies. Using our new data, we reconstruct organic-carbon mass accumulationrates in detail through OAE 2 and discuss the significance of these new data forunderstanding palaeoceanographic conditions during this major palaeoceanographic event. [ABSTRACT FROM AUTHOR]

Precise and accurate determinations of the heavy to light ratios of oxygen and hydrogen isotopes in water are one of the main tools in stable isotope-base investigation of the past and present dynamics of the hydrological cycle (including palaeoclimate studies). However, while (usually and desirably) great care is taken when analyses are performed in the laboratory, a similar level of care during collection, storage, transport and general handling of the water samples before analyses is sometime overlooked. Thus, based on observations of what went wrong with several samples we have analyzed, we present here the results of several tests we have performed to ensure the best treatment of water samples between the moment of collection and that of analysis. We have set-up several experiments to mimic the conditions during sample collection, storage and transport, including leaking, poorly-closed and filled to various degrees vials; storage at different temperatures (between -20 and +30 degrees Celsius) and variable time spans (days to months), secondary evaporation etc. We have found that except for samples kept at low temperatures in fully-closed and sealed HDPE (or glass) vials, the initial stable isotope composition of the water in all other experiments was affected, to variable extent, by post-sampling processes. We will discuss these processes and present limits on storage type, time and conditions below which the samples become useless for scientific purposes. [ABSTRACT FROM AUTHOR]

The Future Climate For Africa programme aims to generate fundamentally new climate science focused on Africa, and to ensure that this science has an impact on human development across the continent. Funded by the UK Department for International Development and the Natural Environment Research Council, this programme is generating new insights into drivers of climate variability and change in the different regions of Africa. The programme has a focus on areas of climate science which can inform development decisions with long-term consequences. For example, the considerable investments being made in new infrastructure across the continent need to be future-climate proofed. This drives a need to improve knowledge of how climate change will affect, amongst other things, the frequency and severity of intense storms and droughts, and the occurrence of agriculturally-damaging dry spells. The provision of reliable future climate information for Africa is compromised by uncertainties in the water cycle and in the projections of variability of regional circulations within CMIP5 and CORDEX simulations. The representation of extreme rainfall is considered to be particularly uncertain due to the limitations of convective parameterisations used within global and regional climate models. We will present examples of new insights from the programme, including analysis of a unique convection-permitting pan-African simulation of current and future climate. [ABSTRACT FROM AUTHOR]

Evapotranspiration plays a key role in hydrologic catchment dynamics. In order to quantify its influence on the hydrologic system we chose to investigate its impact on the ages of water flowing through and residing in a model catchment. How old is water that evaporates from a catchment and how old is water that plants take up and transpire? Furthermore, which factors control whether this evaporated and transpired water is younger or older when it leaves the catchment? We employed a physically-based spatially explicit 3D model to investigate how, amongst other factors, rooting depth and LAI influence water age distributions in different physical environments. This gives indications on how specialized vegetation alters the dynamics of the water cycle. Our results show that evapotranspiration can be both younger and older than streamflow depending on the specific vegetation and physical catchment properties. For example the tails of transit time distributions (TTDs) of evapotranspiration become heavier and the means become longer in environments with decreasing runoff coefficients and deeper roots. Evapotranspiration also significantly alters the TTDs of the water flowing through the catchment discharging at the outlet: Adding evapotranspiration as a process and an additional pathway for exiting water makes catchment discharge younger – an effect that becomes stronger with decreasing runoff coefficients. [ABSTRACT FROM AUTHOR]

The Tien Shan and Pamir, hosting more than 25'000 glaciers, act as important water towers for the dry, continental lowlands of Central Asia. Most glacier mass balance assessments focus on region-wide, decadal mass changes and only a few address seasonal or annual glacier mass balances. The regional annual variability is thus far poorly understood. However, it is essentially needed to improve our understanding of glacier runoff contribution. Here, multi-annual glacier mass changes derived from remote sensing were complemented with seasonal to annual mass balance series inferred from modelling closely constrained with repeated transient snowline observations on a regional scale. To derive annual time series, transient snowline observations were used to calibrate an accumulation and temperature-index melt model for each year and glacier individually. The modelled decadal mass balance was constrained with glacier specific geodetic mass balances calculated from satellite stereo images. We calculated geodetic mass loss from 2004 to 2012 and annual surface mass balance time series from 2000 to 2017 for the Tien Shan and Pamir. A geodetic mass loss of -0.52 ± 0.53 m w.e. yr-1 was calculated for the Tien Shan and -0.24 ± 0.43 m w.e. yr-1 for the Pamir from 2004 to 2012. First results from transient snowline-constrained modelling confirmed the decadal mass loss ranging from -0.36 ± 0.32 to -0.44 to ± 0.32 m w.e. yr-1 for 2000 to 2017 for the subranges Kyrgyz Ala-Too (Tien Shan), the Pamir-Alay (Pamir) and the Akshiirak range (Tien Shan). Lower rates of mass loss was encountered for the early years of the study period and exceptionally negative balances were found for most glaciers in 2008. Our results show a significant trend to increased mass loss for the Pamir-Alay and the Kyrgyz Ala-Too, accompanied with a moderate increase of the interannual variability with time. Annual variability is similar for the Kyrgyz Ala-Too and Pamir-Alay and is considerably smaller for the Akshiirak massif. For Akshiirak, the interannual variability seems to have increased in recent years, however, no significant trends in mass balance were observed. Our time series, annually tied to transient snowline observations and linked to the geodetic estimates at the decadal scale, enable the analysis of yearly mass balance variability for glaciers in a region with few in situ measurements. Moreover, they deliver important baseline data for in depth analysis of the glacier response to climate fluctuations and enable to analyse the importance of glacier melt contribution to the hydrological cycle with an enhanced temporal resolution. [ABSTRACT FROM AUTHOR]

Land surface models (LSMs) have traditionally been designed to focus on providing lower boundary conditions to the atmosphere with less focus on hydrological processes. State of the art application of LSMs include land data assimilation system (LDAS) which incorporates available land surface observations to provide an improved realism of initial surface conditions. While improved representations of the surface variables (such as soil moisture and snow depth) make LDAS an essential component of any Numerical Weather Prediction (NWP) system, the related increments remove or add water, potentially having a negative impact on the simulated hydrological cycle by opening the water budget.This work focuses on evaluating how well NWP configurations are able to support hydrological applications, such as the Global Flood Awareness System, in addition to the traditional weather forecasting. River discharge simulations from two climatological reanalyses, based on ECMWF's new ERA5 dataset, were compared: one 'online' set which includes land-atmosphere coupling and LDAS with an open water budget, and also an 'offline' set with a closed water budget and no LDAS. From these two datasets, a range of hydrological and atmospheric variables were analysed globally.It was found that while the online version of the model with land-atmosphere coupling and LDAS largely improves temperature and snow depth conditions, it causes significant discharge biases in certain areas and poorer representation of peak river flow, particularly in snowmelt-dominated areas in the high latitudes. For example, the systematic negative increments in snow covered areas seem to correct for a significant weakness of the current ECMWF LSM snow scheme, which melts the snow too slowly. Without addressing such issues there will never be confidence in using LSMs for hydrological forecasting applications across the globe. This type of analysis should be used to diagnose where improvements need to be made; considering the whole Earth System in the data assimilation and coupling developments is critical for moving towards the goal of holistic Earth System approaches. [ABSTRACT FROM AUTHOR]

When characterising regional or global climate, due to its implications for both local impacts and the environmental water cycle, rainfall is one of the most important atmospheric variables to be considered. For this reason, annual and seasonal trends of hourly to daily rainfall extremes have been an important object of climatological studies in the past. In the context of the project INTEXseas (An integrated weather-system perspective on the characteristics, dynamics and impacts of extreme seasons), funded by the European research council (ERC), extreme rainy seasons are introduced as a new concept in climate research.In this study, an extreme rainy season is defined as an anomalously 90-days wet period experienced by a region. Using daily rainfall fields of multi-year global gridded datasets from reanalyses and climate simulations, we discuss the particularities of the identified extreme wet seasons in each region and we make a point on the relationship between the anomalously high seasonal averages and the number and nature of the extreme short-term weather events included in these averages. To gain an insight into the different aspects of extreme wet seasons in different regions of the world, our results are discussed also taking into consideration the amplitude of anomalies of the fields of the atmospheric water budget terms that contribute to rainfall, i.e., surface evaporation and the vertical integral of the horizontal moisture flux divergence. [ABSTRACT FROM AUTHOR]

Spatially distributed hydrologic models coupled with atmospheric models have the potential to improve the prediction of the impacts of atmospheric extremes on the terrestrial water cycle. However, systematic deficiencies have been reported for coupled atmospheric-hydrologic simulations, which are, to a large extent, attributed to the parameterisation of hydrologic processes. Thus, the identification or development of efficient hydrologic process parameterisations is a necessary step towards skilful coupled hydrometeorologic applications. This study aims to investigate the sensitivity of modelled runoff to the infiltration and drainage process parameterisations of the unified Noah Land Surface Model (LSM). The Noah LSM-modelled runoff is one of the inputs into the WRF-Hydro distributed hydrologic model. Single soil column model simulations are performed using a subset of functions and routines of the Noah LSM code. The adjusted code is used in simulations with varying precipitation inputs, antecedent soil moisture conditions, soil types and model time steps. The infiltration parameter REFKDT and the parameter SLOPE controlling the drainage at the bottom of the soil column are tested using different combinations of their values and the amount of generated runoff is examined. The results of such type of model sensitivity can provide us with useful insight into how precipitation is partitioned to runoff and infiltration into the soil column, and how the model time step and different parameter values must be selected in the case of spatially distributed coupled atmospheric-hydrologic model simulations. [ABSTRACT FROM AUTHOR]

Water-use efficiency (WUE) describes the trade-off between the amount of assimilated carbon and transpired water, connecting the plant carbon and water cycles at leaf-level. The carbon isotope composition (δ13C) of plant material can be used to infer WUE, even as a screening tool in large-scale studies or across historical timelines. A critical component of this inference is an accurate estimate of mesophyll conductance (gm), which describes the ability of CO2 to diffuse across the interior of the leaf. Although gm is similar in magnitude to stomatal conductance (gs), it has been measured less often, especially under field conditions and at high temporal resolution. We mounted an isotopic CO2 analyser (CRDS) on a field photosynthetic gas-exchange system to make continuous online measurements of gm, gs, net photosynthesis, and WUE in mature Pinus sylvestris trees in June/July, 2017. Mean values for gm were 0.33 (SE = 0.03) mol CO2 m-2 s-1 bar-1, and for gm / gs, were 2.3 (SE = 0.2). These high-resolution measurements highlighted the asynchronous diurnal behaviour of gm and gs. While gs declined from around 09:00, gm remained near its maximum throughout the morning and midday. We suggest that the high gm played a role in supporting an extended Anet peak throughout the morning, despite stomatal closure. We compared estimates of photosynthetic WUE calculated as Anet/E and from δ13C, based on three frequently assumed patterns of gm: constant gm/gs, constant but finite gm, or infinite gm. We found that considering constant, finite gm or gm/gs yielded similar results on a diurnal scale, while assuming infinite gm led to over-estimation of WUE. Taken together, the results highlight the importance of high-resolution gm measurements on the modelling of net photosynthesis and WUE and show that, even under field conditions, it is now possible to acquire such gm data with a CRDS coupled to a continuous gas-exchange system. Finally, we present a comprehensive model to calculate WUE from δ13C, accounting for ternary effects and the effect of day respiration on the observed discrimination. [ABSTRACT FROM AUTHOR]

The capillary fringe (CF) is characterized by steep redox gradient, that is thoughtto be a hot spot for biogeochemical processes. Understanding chemical fate andtransport in the CF is significant, however, biogeochemical dynamics here are poorlyunderstood due to the transient nature of chemical and hydrologic conditions, and thedifficulty to measure at great depth. The inspiration of this research is from theoperation of the soil aquifer treatment (SAT) system of the Shafdan plant, Israel,where the hydrological regime is intense. Outside the Shafdan SAT system, thewater table is at 30 to 40 m depth. Hydrogeophysics is a developing field which useminimally intrusive and quick response methods to monitor hydrological properties. Ofspecial interests are the spectral induced polarization (SIP) and self-potential (SP)methods, as they are more sensitive to the interface between the solid and aqueousphases. The challenge lies on linking the geo-electrical response with biogeochemicalprocesses. We conducted continuous soil column experiment (size: 19.3 × 9.9 × 90 cm3) with theShafdan soil to study nitrogen cycle under hydrologic dynamics (groundwater fluctuationversus local infiltration) across the CF. We consider static experiment (static groundwatertable), periodic pulse experiment (constant groundwater table with intermittentinfiltration), and several dynamic experiments (fluctuating groundwater table subjected todrying-rewetting cycles). Preliminary results of SIP signals showed a good response tonitrogen species (NO3−and NH4+), dissolved organic carbon, CO2 emission, and majordissolved ions (Na, K, Ba, Ca, S, Mg, Fe, Mn, P), water content, matrix potential and Eh.They are likely induced by (1) biogeochemical processes of the water chemistry underdifferent redox states (that are primarily related to water saturation); and (2) adsorption anddesorption of cations to the soil surface and cation exchange between the soil surface andaqueous phase. SP signals are shown to be effective to locate the hot zone of biogeochemicalprocesses. The outcome of this research will not only increase the potential use of SIP and SPmethods across the CF, but also afford suggestions for efficient operation of the Shafdan SATsystem. [ABSTRACT FROM AUTHOR]

Snow water equivalent (SWE) is a key property of the seasonal snow cover. The water stored in the snowpack is a crucial contribution to the hydrological cycle in mountain areas. Estimating the spatial distribution and temporal evolution of SWE in mountain region is currently considered as one of the most important unsolved problems in snow hydrology. Direct measurements of SWE are still essential but are scarce and mostly non-continuous (manual measurements) or rather expensive (automatic scales or snow pillows). Recently, a novel in-situ measurement technique based on freely-available L-band Global Navigation Satellite Signals (GNSS) signals, like GPS signals, showed promising results in deriving SWE. This snow measurement technique is in general based on the combination of GNSS carrier phase measurements indicating signal time delay and GNSS signals strength information indicating signal attenuation within the snowpack. To derive the SWE, the signal time delay and attenuation are obtained from the signal differences between a GNSS antenna buried below the snowpack and a reference antenna above the snow cover. This method has been tested and validated at the high-alpine test site Weissfluhjoch (Eastern Swiss Alps, 2540 m asl.) and seems to work well for the snow conditions met at this elevation. However, the snow characteristics can vary considerably depending on location and elevation. At lower elevations the snow cover is normally shallower and is more frequently subject to melt-freeze cycles leading to faster snow aging and different snow densities. Moreover, it was not yet tested, if a rapid transition from dry to wet snow conditions is a challenge for deriving SWE by this GNSS method. To test these potential issues and aiming to improve our method, we installed four GNSS stations along a steep elevation gradient (820 m, 1185 m, 1510 m, and 2540 m asl.) within only a few kilometres in the Eastern Swiss Alps in autumn 2018. For validation purposes, the snow height is monitored continuously and automatically with additional sensors. SWE is measured at least biweekly at all locations. Moreover, at the two higher elevations, SWE is also measured continuously with snow scales. We present preliminary results from the ongoing season along this steep elevation gradient. The latest GNSS processing steps as well as our recent integration of Galileo besides GPS signals, which is particular useful to increase GNSS satellite visibility for valley sites, will be shown. Finally, we will assess whether the method is suitable for operational use at different elevations, in steep valley sites and under various snow conditions for deriving SWE continuously with reasonable costs. [ABSTRACT FROM AUTHOR]

The large range of stable oxygen isotope range values of for phosphate-bearing minerals and dissolved phosphate of both inorganic or organic origins requires the use of calibrated material of in-house made internal standards of silver phosphate of which isotopic ratios must closely bracket those of studied samples. Such calibrated materials do not exist yet in the various catalogs of stable isotope calibrated standards. Therefore, we propose a simple and cheap protocol to synthesize in house silver phosphate in with a predictable wide range (≈ 40‰) of oxygen isotope isotopic compositions. It is based on the equilibrium isotopic fractionation factor and the kinetics and temperature of isotopic exchange in the phosphate-water system. Silver phosphate crystals are obtained from a highly soluble salt such as KH2PO4 that is dissolved in water of known oxygen isotope composition. Isotopic exchange between dissolved phosphate and water takes place at a desired and constant temperature into Ace Glass™pyrex tubes that are placed in a high precision temperature regulation oven for run-times defined by the user. Samples of dissolved phosphate are withdrawn at desired times, quenched in cold water, and quantitatively precipitated as silver phosphate. We propose an "Excel calculation sheet" that computes the oxygen isotope composition of the precipitated silver phosphate depending as a function of on time t (≤ 1 month), temperature T (recommended range from 110°C to 130°C with a precision of ±0.5°C) and the oxygen isotope compositions of both reactants KH2PO4 and H2O at t = 0. Predicted oxygen isotope compositions of synthesized silver phosphate range from -7 to +31‰ VSMOW for a temperature range comprised between 110°C and 130°C and a range of water delta18O from -20 to +15‰ VSMOW. We present practical applications of this protocol comparing theoretical values with real measurements obtained from phosphate samples generated using this method. [ABSTRACT FROM AUTHOR]

Canopy water retention plays important role in the water cycle. This work summarizes theautomation efforts of interception measurement at the Hidegvíz Valley ExperimentalCathchment (Sopron, Hungary). There are several years long time-series of throughfall andstemflow data, collected in the research catchment with labor intensive, manualrecording in different sites. The high spatial and temporal variability of the processsuggest to increase sampling point numbers and time resolution of the measurement.The only possible way is to fulfill this requirement is to introduce modern digitalequipments. The alder dominated plot in the riparian zone, as an agroforestry area, of the Rák Brook isalready equipped with a digital datalogger. Both the stemflow and throughfall are collected inlarge containers. The water level in that containers is registered by vented pressuretransducers. The measurements gives information about the temporal variability,but can not represent spatial differences. In this work we introduce beyond ourrecent efforts in interception measurement the possible enhancement directionstoo. This research has been supported by the EFOP-3.6.2-16-2017-00018 in University ofSopron project, and the corresponding author&#x2019;s work has been also supported by the JánosBolyai Scholarship of the Hungarian Academy of Sciences. [ABSTRACT FROM AUTHOR]

The isotopic composition of atmospheric water vapour is influenced by evaporation at the source and cloud processes. Due to the advection of water vapour, it is immediately coupled to the atmospheric circulation, from large-scale weather systems to vertical mixing in the turbulent atmospheric boundary layer. Combined measurements of water vapour and precipitation isotopic compositions can provide valuable insight into local and remote processes affecting the hydrological cycle. Here, we present an analysis of the influence of atmospheric circulation on the isotopic composition of near surface water vapour and precipitation continuously monitored at Bergen in Southern Norway (60.38°N, 5.33°E), located downstream of the North Atlantic storm track, between December 2016 and March 2019. The precipitation was sampled manually per precipitation event on a daily basis on the rooftop platform (54 m a.s.l, 25 m above ground) of the Geophysical Institute at Bergen and analysed for δ¹⁸O, δD, and d-excess on a laser spectrometer (L2140-i, Picarro Inc.). Ambient air was continuously pumped from a heated inlet at the same location to a laser spectrometer (L2130-i, Picarro Inc.). In addition, temperature, relative humidity, wind speed and direction, and precipitation rate were measured at a nearby automatic weather station.The two-year measurement period covered several contrasting seasons. The summer of 2017 was the wettest summer of last 50 years, in contrast to the summer of 2018 which was extremely dry and warm with long heat waves recorded. The winter of 2017/2018 was cold with unusually high snow accumulation, whereas the winter of 2018/2019 was relatively warm with mainly rain events. The strong inter-annual contrasts are associated with clear differences in seasonal circulation patterns, which are reflected by substantial differences in both surface water vapour and precipitation isotopic compositions. Furthermore, synoptic and seasonal variations in the surface water vapour and precipitation isotopic compositions coincide with the shifts in the moisture sources and transport distance, obtained from a Lagrangian moisture source diagnostic. Finally, we discuss the long-term observations at Bergen in the context of measurements from a wider network of water vapour isotopic composition monitoring in the region of the North Atlantic and the Nordic Seas. [ABSTRACT FROM AUTHOR]