Search

The joint probability of precipitation and soil moisture is here investigated over Europe with the goal to extrapolated meaningful insights on the potential joint use of these variables for the detection of agricultural droughts within a probabilistic modeling framework. The use of copulas is explored as a parametric approach often used in hydrological studies for the analysis of bivariate distributions. The analysis is performed for the period 1996–2020 on the ERA5 precipitation and LISFLOOD soil moisture datasets, both available as part of the Copernicus European Drought Observatory. The results show an overall good correlation between the empirical frequency series derived from the two datasets (Kendall’s τ = 0.42±0.1), but also clear spatial patterns in the tail-dependence derived with both non-parametric and parametric approaches. About half of the domain shows symmetric tail-dependences, well reproduced by the Student-t copula, whereas the rest of the domain is almost equally split between low and high tail-dependences (modeled with the Gumbel family of copulas). These spatial patterns are reasonably reproduced by a random forest classifier, suggesting that this outcome is not driven by chance. This study stresses how a joint use of precipitation and soil moisture for agriculture drought characterization may be more beneficial in areas with strong low tail-dependence, such as southern France, northern UK, northern Germany, and Denmark in this study, and how this behavior should be carefully considered in drought studies.

Funding Information: This open-access publication was funded by the University of Freiburg. Funding Information: Financial support. The project is supported by the Wassernetzwerk Baden-Württemberg (Water Research Network of the State Baden-Württemberg), which is funded by the Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg (Ministry of Science, Research and the Arts of the State Baden-Württemberg) (grant no. AZ. 7532.21/2.1.6) and Maa-ja vesitekniikan tuki ry foundation. Doris E. Wendt acknowledges her support as part of the NERC-funded Groundwater Drought Initiative (NE/R004994/1). Lucy J. Barker was supported by the Natural Environment Research Council (NE/R016429/1) as part of the UK-SCAPE programme delivering National Capability. The contributions of Mirek Trnka, Lenka Bartošová, and Jaak Jaagus have been supported by SustES – Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions (CZ.02.1.01/0.0/0.0/16_019/0000797). Publisher Copyright: © 2022 Veit Blauhut et al. Drought events and their impacts vary spatially and temporally due to diverse pedo-climatic and hydrologic conditions, as well as variations in exposure and vulnerability, such as demographics and response actions. While hazard severity and frequency of past drought events have been studied in detail, little is known about the effect of drought management strategies on the actual impacts and how the hazard is perceived by relevant stakeholders. In a continental study, we characterised and assessed the impacts and the perceptions of two recent drought events (2018 and 2019) in Europe and examined the relationship between management strategies and drought perception, hazard, and impact. The study was based on a pan-European survey involving national representatives from 28 countries and relevant stakeholders responding to a standard questionnaire. The survey focused on collecting information on stakeholders' perceptions of drought, impacts on water resources and beyond, water availability, and current drought management strategies on national and regional scales. The survey results were compared with the actual drought hazard information registered by the European Drought Observatory (EDO) for 2018 and 2019. The results highlighted high diversity in drought perception across different countries and in values of the implemented drought management strategies to alleviate impacts by increasing national and sub-national awareness and resilience. The study identifies an urgent need to further reduce drought impacts by constructing and implementing a European macro-level drought governance approach, such as a directive, which would strengthen national drought management and mitigate damage to human and natural assets.

The JRC PESETA IV study shows that ecosystems, people and economies in the EU will face major impacts from climate change if we do not urgently mitigate greenhouse gas emissions or adapt to climate change. The burden of climate change shows a clear north-south divide, with southern regions in Europe much more impacted, through the effects of extreme heat, water scarcity, drought, forest fires and agriculture losses. Limiting global warming to well below 2°C would considerably reduce climate change impacts in Europe. Adaptation to climate change would further minimize unavoidable impacts in a cost-effective manner, with considerable co-benefits from nature-based solutions., JRC.C.6-Economics of Climate Change, Energy and Transport

This report presents an ecosystem assessment covering the total land area of the EU as well as the EU marine regions. The assessment is carried out by Joint Research Centre, European Environment Agency, DG Environment, and the European Topic Centres on Biological Diversity and on Urban, Land and Soil Systems. This report constitutes a knowledge base which can support the evaluation of the 2020 biodiversity targets. It also provides a data foundation for future assessments and policy developments, in particular with respect to the ecosystem restoration agenda for the next decade (2020-2030). The report presents an analysis of the pressures and condition of terrestrial, freshwater and marine ecosystems using a single, comparable methodology based on European data on trends of pressures and condition relative to the policy baseline 2010. The following main conclusions are drawn: - Pressures on ecosystems exhibit different trends. - Land take, atmospheric emissions of air pollutants and critical loads of nitrogen are decreasing but the absolute values of all these pressures remain too high. - Impacts from climate change on ecosystems are increasing. - Invasive alien species of union concern are observed in all ecosystems, but their impact is particularly high in urban ecosystems and grasslands. - Pressures from overfishing activities and marine pollution are still high. - In the long term, air and freshwater quality is improving. - In forests and agroecosystems, which represent over 80% of the EU territory, there are improvements in structural condition indicators (biomass, deadwood, area under organic farming) relative to the baseline year 2010 but some key bio-indicators such as tree-crown defoliation continue to increase. This indicates that ecosystem condition is not improving. - Species-related indicators show no progress or further declines, particularly in agroecosystems. The analysis of trends in ecosystem services concluded that the current potential of ecosystems to deliver timber, protection against floods, crop pollination, and nature-based recreation is equal to or lower than the baseline value for 2010. At the same time, the demand for these services has significantly increased. A lowered potential in combination with a higher demand risks to further decrease the condition of ecosystems and their contribution to human well-being. Despite the wide coverage of environmental legislation in the EU, there are still large gaps in the legal protection of ecosystems. On land, 76% of the area of terrestrial ecosystems, mainly forests, agroecosystems and urban ecosystems, are excluded from a legal designation under the Bird and Habitat Directives. Freshwater and marine ecosystems are subject to specific protection measures under the Water Framework and Marine Strategy Framework Directives. The condition of ecosystems that are under legal designation is unfavourable. More efforts are needed to bend the curve of biodiversity loss and ecosystem degradation and to put ecosystems on a path to recovery. The progress that is made in certain areas such as pollution reduction, increasing air and water quality, increasing share of organic farming, the expansion of forests, and the efforts to maintain marine fish stocks at sustainable levels show that a persistent implementation of policies can be effective. These successes should encourage us to act now and to put forward an ambitious plan for the restoration of Europe’s ecosystems., JRC.D.3-Land Resources

With this report, the reader finds an overview of the changes, upgrades and new features created in the European Drought Observatory (EDO) and the Global Drought Observatory (GDO) and made in 2019. The year proved relatively quiet concerning drought events in Europe; the subcontinent was only affected in the Baltics, although fires broke out vigorously in the Balkans, Spain and Russia. Thanks to the recent juvenile concern with regard to the heating up of the climate, drought events and forest fires drew more public-attention. Our reaction upon this concern in the Global Drought Observatory is the development of a new group of data, which we call Drought Mitigation. With more people genuinely concerned in the effect of our alternation of the properties of the lower atmosphere, we take up the task to provide guidelines for repair and adaptation. Higher temperatures imply that air depletes more vapour from vegetation and soil, leading to more intense droughts or floods. Consient management of our fresh water resources and massive tree planting are measures that can have significant impact on the effects of a Drought, Forest Fires or also Flood events. Therefore, we started with including the results of the often-cited research result regarding reforestation potential of the Crowther Lab as a layer in the Global Drought Observatory. We completed our work with enriching data describing dams with data regarding the location, name and quantitative characteristics of dams as an additional layer. We worked on the integration of the GRACE Dataset, which gives us an actualized satellite born, insight in the depletion of groundwater resources. We created a new index, alerting drought impacts on protected wetlands. Droughts events in these areas might affect rare species living in these protected wetlands, thus creating a link to the biodiversity crisis. The drought alerting mechanism we developed thus far were human centred. With this new index and with the Crowther Lab reforestation inventory we hope to correct this one species view of the past, learning to share our territory with all species, also during hard times of a drought disaster. With these additions, we hope that EDO and GDO will give you a better overview of the impacts of drought events, not only for our economy but also for our shared ecosystems and their services to us. Finally note that we engage in a project to export EDO and GDO knowledge and software to African regional partners. Thus enabling them to set up drought observatories in Africa just as if we did for South- and Central America. Such a collaboration works both ways, we understand better the impacts of Drought events in their region and we learn from their practical skills with regard to make things work in a challenging environment, whilst we can give them working drought observatory software, practical manners to, almost, fully automate the filling and updating of the systems combined with our specific expertise on droughts build up in the last 12 years., JRC.E.1-Disaster Risk Management

The study assesses how climate change could affect Europe in eleven impact areas. Under a high warming scenario, several climate impacts show a clear geographical north-south divide. Most of the welfare losses, assessed for six impact areas, would be greatly reduced under a 2ᵒC scenario., JRC.C.6-Economics of Climate Change, Energy and Transport

In the context of global warming, droughts are increasingly threatening our societies. They last for months or even years, affecting wide areas and large numbers of people, with single drought events sometimes causing economic damages for several billion Euros. Besides the economic damages, droughts can compromise ecosystems and threat food security in the most vulnerable countries. To reduce drought impacts, drought risk assessments need to be implemented in order to support policy makers and water managers in developing coping strategies and drought management plans. Due to the wide-ranging direct and indirect, often cascading impacts, drought risk assessments need to include information tailored to specific sectors and oriented to the needs of specific users. Drought risk as defined here is the likelihood to incur damages and economic losses during and after a drought and depends on the interactions between three dimensions: 1) the severity and the probability of occurrence of a certain drought event, 2) the exposed assets and/or people, and 3) their intrinsic vulnerability or capacity to cope with the hazard. The characterization of these dimensions and the representation of their interactions over different socio-economic sectors poses several challenges. This document discusses these challenges and proposes a theoretical framework to assess drought risk at global scale in order to provide policy relevant information. Based on the described conceptual approach, the JRC developed the Global Drought Observatory (GDO) as a first operational dynamic drought risk monitor for the entire globe. The report is structured as follows: Firstly, the causes and characteristics of drought events as well as their link with climate variability and climate change are discussed (chapters 1 and 2). Secondly, the concept of drought risk is presented, including a first approach to map drought risk at global scale as a function of hazard, exposure and vulnerability (chapter 3). This framework is then linked to expected impacts in different economic sectors and the environment, including the discussion of case studies from Argentina, South Africa, Syria and the United States (chapter 4). Finally, a brief introduction to the key aspects of drought risk management and an outlook on future challenges and opportunities are presented in chapters 5 and 6., JRC.E.1-Disaster Risk Management

This document reports the results of the analyses performed within the framework of the PESETA3 project regarding the Task 9 - Droughts. The main objective of this task is to provide robust scientific-based information to stakeholders and decision makers on the possible impacts of future climate scenarios on the occurrence of drought events. This report is focused on the analysis of the variations of soil moisture on the European continent, as well as of a soil moisture-based drought severity indicator (DSI), in order to evaluate the possible increase/decrease in future occurrence and severity of soil drought events and the related hazard and risk. Following the guideline of the project, five bias-corrected climatological datasets were used to force the LISFLOOD hydrological model that produces the daily soil moisture maps used in this analysis. These datasets were part of the EURO-CORDEX package and were used to characterize both the present reference period (1981-2010) and the future scenario at the date when a global 2 °C warming will occur according to the RCP8.5 scenario (different for each dataset and around the mid of the century). In the framework of this project, considering the specific purpose of the report, only the RCP8.5 scenario was selected in order to provide a clear indication on the possible future impacts of a strong climate change. The most relevant findings of the analysis depicted a scenario with differences that are statistically significant only on a limited fraction of the continental territories, with negative impacts limited to the Mediterranean and South-western Europe area for both soil moisture (reduction in water availability during both the dry and the wet season) and extreme drought events (increase in drought hazard). Particularly concerning is the increase of drought hazard over areas that are already drought prone and characterized by semi-arid climate, even if a limited impact on drought risk is expected due to the low present exposure and vulnerability of the same regions. Overall, it appears clear from this study that the EU goal to limit the global warming at 2 °C, as compared to the average temperature in pre-industrial times, will confine the variations in drought impacts to a minor fraction of the European continent in the near future, as shown by the obtained results., JRC.E.1-Disaster Risk Management

Dry spells duration and its extent in space, is a key factor in water resources problems. In order to modelling the empirical distribution of dry spells (DS) frequencies observed in Sicily (i.e. in a typical Mediterranean climate), Agnese et al. (2014) successfully applied the two-parameter polylogarithm-series distribution. Because of the strong seasonality characterising Sicily’s rainfall regime, statistical analysis was separately applied to two data sets, referred to as “dry” and “wet” seasons, respectively. In this work, a similar analysis was carried out for a set of 26 DS time-series recorded in a large area (about 30000 km2), including Piedmont and the Aosta Valley. Area altitude ranges between 100 to almost 5000 m a.s.l., and the Mediterranean sea is at about 20 km distance. Main climate character in the whole area is colder and more humid than that of Sicily, and it varies noticeably within the area itself, likely because of the complex role of geomorphology on rain and snow occurrence. Also, partition between rain and snow is evaluated. A subdivision in homogeneous subareas is found which is related to the main weather types occurring. In this work the focus is on the longer dry spells.

Daily precipitation records exist spanning several decades. A valuable amount of climatic information exists in the time-series of interarrival times (IT), defined as the succession of times (number of days) elapsed from a rainy (or snowy) day to the one immediately preceding it.In a previous work, Agnese et al. (2014) have been successfully tested some probabilistic modelling of rain occurrence on Sicily rainfall data; particularly, the better fitting of IT’s observed frequencies was obtained by 3-parameter Lerch-series distribution. In this work thisdistribution is tested on 70 years of 20 precipitation time-series taken in the North-West Italy, both in the plain and in the mountains, up to the 2000 meters altitude. In such Mediterranean climatetwo markedly different behaviours were observed in the dry semester (April to September) and in the wet one (October to March). A better fit was obtained with that simple subdivision of the year, in comparison with the whole year modelling. However, the NW Italy climate is both more similar to the Central Europe one, and it is deeply influenced by the higher peaks of the Alps. Therefore the seasonality of daily precipitation data is much more complicated. Usually spring and fall are the seasons characterized by the higher precipitations, but the convective vs. frontal events also play a role in the IT distributions. In this work, different subdivisions were compared with the whole year fitting. The whole year Lerch distributions successfully fitted the data in a part of the time series, opening the way to interesting climate applications.

Large area estimations of land surface fluxes can be a useful operational tool for up-scaling local measurements and can serve as an upper-boundary condition for higher spatial resolution applications. Given hourly measurements of radiometric surface temperature from a geostationary satellite, it is possible to derive the partitioning of energy fluxes based on the influence of the evapotranspiration process on morning surface temperature rise. In this work, the Atmosphere-Land Exchange Inverse (ALEXI) model and the Dual Temperature Difference (DTD) approach were applied in order to relate the sensible heat flux to time-differential remote observations of surface temperature obtained from Meteosat satellite data. Copyright © 2012 IAHS Press.

La rilevanza assunta dal risparmio della risorsa idrica negli ultimi anni ha spinto verso una corretta quanti cazione delle perdite legate al processo evapotraspirativo, al ne di una gestione parsimoniosa della risorsa stessa. In particolare nei sistemi agricoli soggetti a stress severo, sia la misura che la stima dell'evapotraspirazione (ET) ad un'adeguata risoluzione spaziale e temporale sono uno dei principali problemi da a rontare per la comunit a scienti ca. Recentemente, le tecniche di telerilevamento sono divenute un ulteriore strumento a supporto della modellistica idrologica distribuita; in particolare, le immagini acquisite nelle onde corte e nell'infrarosso termico risultano essere di notevole interesse. In questo contesto, i due scopi principali di questa ricerca sono stati: la quanti cazione dell'accuratezza delle misure micro-meteorologiche in sistemi agricoli vegetati con colture alte e sparse; e l'analisi dei modelli basati su dati telerilevati per la stima di ET ad alta risoluzione spaziale e temporale. L'area di studio e caratterizzata da un tipico clima Mediterraneo e da colture olivicole, e si trova localizzata nei pressi di Castelvetrano (Italia). Quest'area e stata oggetto nella primavera-estate 2008 di una campagna di misura mediante istallazioni eddy covariance e scintillometrica, e, contestualmente, dall'acquisizione di 7 immagini multi-spettrali ad alta risoluzione. L'analisi delle misure micro-meteorologiche ha permesso di quanti care l'accordo tra le due tecniche e ha portato allo sviluppo di un nuovo approccio di calibrazione dei dati scintillometrici. Inoltre, alcune ipotesi alla base della stima dei ussi giornalieri sono state discusse in dettaglio. L'analisi degli algoritmi per la simulazione dei processi di scambio nel continuo suolo-pianta-atmosfera e stata focalizzata: i) sulle stime hot-spot di ET mediante un approccio di bilancio energetico residuale, ii) sulla stima in continuo di ET alla scala di campo mediante diversi approcci. Quest'ultima analisi ha evidenziato i buoni risultati del modello accoppiato energetico/idrologico per la stima dei ussi di acqua ed energia sia a scala oraria che giornaliera. In ne, l'applicabilit a di due approcci di data assimilation e stata testata utilizzando sia osservazioni arti ciali che reali. In view of the increased relevance of water saving issues in the last decades, the correct quanti cation of water loss due to evapotranspirative process became fundamental for a parsimonious management of this resource. Especially in agricultural systems subjected to severe water stress, both the measurement and the modelling of evapotranspiration (ET) at adequate temporal and spatial resolution, are important topics for the hydrologist scienti c community. Recently, the remote sensing techniques provide an additional tool to support the hydrologic spatially distributed models; in particular, images acquired in the short-wave and the thermal spectral regions have quite interesting applications. Within this framework, the two principal aims of this work were: to quantify the accuracy of surface energy uxes measured by micro-meteorological techniques in sparse tall vegetated system; and to analyze the capability of remote sensing-based approach to retrieve ET at high temporal and spatial resolution. The selected test site was an area characterized by Mediterranean climate and olive crops, located near Castelvetrano (Italy). This area, during the spring-summer period in 2008, was interested by in-situ measurements campaigns with eddy covariance and scintillometer instruments, and, contextually, by the acquisition of 7 high resolution multi-spectral images. The analysis of micro-meteorological measurements allows to evaluate the agreement between these techniques in the study site, also by means of a novel algorithm for the elaboration of scintillometer data. Moreover, some fundamental hypothesis of daily uxes estimation was critically discussed. The analysis of the algorithms for the simulation of the exchange processes in the continuum soil-plant-atmosphere was focused on: i) the retrieval of hot-spot ET maps by means of residual energy balance approach and ii) the continuous ET estimation at eld scale using di erent approaches. This latter analysis highlights the good performance of a coupled energy/hydrological model for the assessment of energy and water uxes at both hourly and daily scale. Finally, the applicability of two data assimilation schemes was tested using both arti cial and real observations.

Phoenix canariensis represents one of the most relevant ornamental plants within Mediterranean environment. In the last few years the infestation of a curculio coleopteron, namely the Rhynchophorus ferrugineus, caused a widespread decimation of these palms. Unluckily damages caused by the insect are evident only in the advanced phase of the disease making futile almost any plant treatment. Early warning of this disease may represents the only way to setup efficient actions to fight the coleopteron in trees where it takes over, thus limiting its spreading in contiguous palms. This research aims to achieve the former result by processing: i) short and long-wave images of the crown acquired during day-time by a balloon platform, and ii) a time series of thermal images of the trunk recorded during night-time on the field. The research is based on the hypotheses that: j) the disease induces changes of both transpiration processes and crown shape, because the damages of vascular tissues; jj) the local increase of temperature within the trunk, due to anaerobic fermentation established within the palm, extends up enough to surface to be diachronically analyzed to localize the disease core. © (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Recent studies showed that the sensible heat flux (H) measured with an array of eddy-correlation system has an high spatial and temporal variability over sparse tall vegetation, such as olive trees, whereas H determined with a displaced-beam laser scintillometer (DBLS) appeared to behave more stable. In this study, the results are shown of two field experiments performed over an olive tree plantation in Sicily in 2007 and 2008, in order to investigate the applicability of a DBSL in combination with remote sensing techniques for the actual evapotranspiration assessment. In 2007 the laser beams was closer to the top of the canopy than in 2008. Various aspects of the scintillation method will be discussed, such as uncertainty about Monin-Obukhov similarity relations for dissipation of kinetic turbulence energy (e), the structure parameter of temperature (CT2), effects of the roughness sub-layer and the outer scale of turbulence. Finally, a practical method will be proposed for routine applications in agriculture of the DBLS over sparse tall Mediterranean vegetation.