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3. Intraday probabilistic forecasts of solar resources with cloud scale-dependent autoregressive advection

Author

Carpentieri, Alberto, Pulkkinen, Seppo, Nerini, Daniele, Folini, Doris, Wild, Martin, and Meyer, Angela

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Solar energy supply is usually highly volatile which limits its integration in the power grid. Accurate probabilistic intraday forecasts of solar resources are essential to increase the share of photovoltaic (PV) energy in the grid and enable cost-efficient balancing of power demand and supply. Solar PV production mainly depends on downwelling surface solar radiation (SSR). By estimating SSR from geostationary satellites, we can cover large areas with high spatial and temporal resolutions, allowing us to track cloud motion. State-of-the-art probabilistic forecasts of solar resources from satellite imagery account only for the advective motion of clouds. They do not consider the evolution of clouds over time, their growth, and dissipation, even though these are major sources of forecast uncertainty. To address the uncertainty of cloudiness evolution, we present SolarSTEPS, the first optical-flow probabilistic model able to simulate the temporal variability of cloudiness. We demonstrate that forecasting the autocorrelated scale-dependent evolution of cloudiness outperforms state-of-the-art probabilistic advection-based forecasts by 9% in continuous ranked probability score (CRPS). This corresponds to an extension of the forecast lead time by about 45 minutes at constant CRPS. Our work is motivated by the scale-dependent predictability of cloud growth and decay. We demonstrate that cloudiness is more variable in time at smaller spatial scales than at larger ones. Specifically, the temporal autocorrelation of cloudiness is related to its spatial scale by a rational function. We also demonstrate that decomposing cloudiness into multiple spatial scales in the forecasts further improves the forecast skill, reducing the CRPS by 10% and the RMSE by 9%., Comment: 17 pages plus appendix, 10 figures. To be submitted

Published
2023

4. Global Estimates of Spatially Distributed Surface Energy Fluxes using Thermodynamic Principles

Author

Gupta, Mayank, Wild, Martin, and Ghosh, Subimal

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Limited surface observations of turbulent heat fluxes result in incomplete knowledge about the surface energy balance that drives the climate system. Here, we developed a novel, purely physics-based analytical method grounded on the thermodynamic principle of maximum power. The approach derives the turbulent heat flux only from the four inputs of incoming and outgoing radiations at the land surface. The proposed approach does not use any parameterization, unlike the existing surface energy balance models, and hence does not suffer from uncertainty due to the same. We validated our methodology with 102 eddy covariance observation stations around the globe with different land use land covers. Using the satellite observations from CERES at a spatial resolution of 1 degree, we have obtained spatially distributed global analytical estimates of Sensible (H), latent heat (LE), and land surface heat storage (delQs) fluxes for the first time. For a global observed land Net radiation of 84 W/m2 from the satellite, we found H, LE and delQs to be 42 W/m2, 40 W/m2 and 2 W/m2, respectively. The theoretical and precise estimates of all surface energy balance components will improve our understanding of surface warming for different land use land covers across the globe.

Published
2022

5. Satellite-derived solar radiation for intra-hour and intra-day applications: Biases and uncertainties by season and altitude

Author

Carpentieri, Alberto, Folini, Doris, Wild, Martin, Vuilleumier, Laurent, and Meyer, Angela

Subjects
Physics - Atmospheric and Oceanic Physics, Computer Science - Machine Learning
Abstract

Accurate estimates of the surface solar radiation (SSR) are a prerequisite for intra-day forecasts of solar resources and photovoltaic power generation. Intra-day SSR forecasts are of interest to power traders and to operators of solar plants and power grids who seek to optimize their revenues and maintain the grid stability by matching power supply and demand. Our study analyzes systematic biases and the uncertainty of SSR estimates derived from Meteosat with the SARAH-2 and HelioMont algorithms at intra-hour and intra-day time scales. The satellite SSR estimates are analyzed based on 136 ground stations across altitudes from 200 m to 3570 m Switzerland in 2018. We find major biases and uncertainties in the instantaneous, hourly and daily-mean SSR. In peak daytime periods, the instantaneous satellite SSR deviates from the ground-measured SSR by a mean absolute deviation (MAD) of 110.4 and 99.6 W/m2 for SARAH-2 and HelioMont, respectively. For the daytime SSR, the instantaneous, hourly and daily-mean MADs amount to 91.7, 81.1, 50.8 and 82.5, 66.7, 42.9 W/m2 for SARAH-2 and HelioMont, respectively. Further, the SARAH-2 instantaneous SSR drastically underestimates the solar resources at altitudes above 1000 m in the winter half year. A possible explanation in line with the seasonality of the bias is that snow cover may be misinterpreted as clouds at higher altitudes.

Published
2022

6. Arctic Oscillation: possible trigger of COVID-19 outbreak

Author

Sanchez-Lorenzo, Arturo, Vaquero-Martinez, Javier, Lopez-Bustins, Joan-A., Calbo, Josep, Wild, Martin, Santurtun, Ana, Folini, Doris, Vaquero, Jose-M., and Anton, Manuel

Subjects
Quantitative Biology - Populations and Evolution, Physics - Atmospheric and Oceanic Physics
Abstract

The current COVID-19 pandemic is having detrimental consequences worldwide. The pandemic started to develop strongly by the end of January and beginning of February 2020, first in China with subsequent rapid spread to other countries with new epicenters of the outbreaks concentrated mainly within the 30-50 degrees North latitudinal band (e.g., South Korea, Japan, Iran, Italy, Spain). Simultaneously, an unusual persistent anticyclonic situation prevailing at latitudes around 40 degrees North was observed on global scale, in line with an anomalously strong positive phase of the Arctic Oscillation. This atypical situation could have resulted in favorable meteorological conditions for a quicker spread of the virus over the latitude band detailed above. This possible connection needs further attention in order to understand the meteorological and climatological factors related to the COVID-19 outbreak, and for anticipating the spatio-temporal distribution of possible future pandemics., Comment: 11 pages, 2 figures

Published
2020

7. Anomalous atmospheric circulation favored the spread of COVID-19 in Europe

Author

Sanchez-Lorenzo, Arturo, Vaquero-Martínez, Javier, Calbó, Josep, Wild, Martin, Santurtún, Ana, Lopez-Bustins, Joan-A., Vaquero, Jose-M., Folini, Doris, and Antón, Manuel

Subjects
Quantitative Biology - Populations and Evolution, Physics - Atmospheric and Oceanic Physics
Abstract

The current pandemic caused by the coronavirus SARS-CoV-2 is having negative health, social and economic consequences worldwide. In Europe, the pandemic started to develop strongly at the end of February and beginning of March 2020. It has subsequently spread over the continent, with special virulence in northern Italy and inland Spain. In this study we show that an unusual persistent anticyclonic situation prevailing in southwestern Europe during February 2020 (i.e. anomalously strong positive phase of the North Atlantic and Arctic Oscillations) could have resulted in favorable conditions, in terms of air temperature and humidity, in Italy and Spain for a quicker spread of the virus compared with the rest of the European countries. It seems plausible that the strong atmospheric stability and associated dry conditions that dominated in these regions may have favored the virus's propagation, by short-range droplet transmission as well as likely by long-range aerosol (airborne) transmission., Comment: 22 pages, 4 figures, Supplementary Information with 8 figures

Published
2020

9. Component-based security under partial compromise

Author

Dehnel-Wild, Martin, Cremers, Cas, and Martin, Andrew

Subjects
005.8
Abstract

In our increasingly connected world, daily life depends on the correct and unimpaired operation of the computers controlling our infrastructure. These systems are increasingly complex, both within the computers themselves, and in the communications between them that create larger systems. This complexity increases both functionality and potential vulnerability. In turn, this makes ensuring the security of these critical systems simultaneously harder and more important than ever. Ensuring that systems are not meaningfully vulnerable to attack requires a wide range of techniques. During design and implementation, the foremost of these is formal verification. Large, real-world systems and protocols made up of multiple computers or components are rarely designed with verification or analysis in mind. By the same token, these same systems have very often proved tricky to analyse formally. Can we meaningfully verify the security properties of large, real-world, multi-component systems, in a reasonable amount of time? Is there value in making the modelling and analysis as fine-grained as we can, or does the extra effort fail to buy us anything? Can these systems still operate correctly and securely even when partially compromised by an attacker? Can we improve the languages and tools we use to model systems under partial compromise? In this thesis, we address these questions through a mixture of theory and practice. We first consider a major power grid communications standard, DNP3. We show that its "Secure Authentication" protocols meet their security goals, and that a previously claimed attack is not possible. We then consider the security of 5G, and its main Authentication and Key-Agreement protocol. Our analysis reveals that 5G-AKA's security relies on unstated assumptions; in practice this means 'correct' implementations can be vulnerable to a security-critical race condition. Our analyses show how far we have to go in terms of resilience under partial compromise. Neither studied system fares well against attackers which control any one of its components: this is no longer acceptable in elements of critical national infrastructure, as these systems increasingly come under sophisticated attack. We then consider the formalisation of partial compromise, building the idea of an attacker controlling part of a system into models from the start. Our new techniques give approachable yet powerful ways to model a wide range of multi-component systems and protocols against fine-grained threat models. We finish with two main conclusions. First, the time is now right for formal methods. We show that precise, fine-grained modelling of complex, multi-component protocols is both possible and valuable in the real world. Second, partial compromise resilience must be built in from the start. With little hope of securing all end-points completely, it is essential that resilience is also built into the network protocols.

Published
2018

10. Vegetation type is an important predictor of the arctic summer land surface energy budget

Author

Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, and Chambers, Scott D.

Published
2022
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11. Trends in observed surface solar radiation and their causes in Brazil in the first 2 decades of the 21st century.

Author

Ferreira Correa, Lucas, Folini, Doris, Chtirkova, Boriana, and Wild, Martin

Subjects
SOLAR surface, SOLAR oscillations, CLOUDINESS, TWENTY-first century, DEVELOPING countries, BIOMASS burning
Abstract

Numerous studies have investigated the long-term variability in surface solar radiation (SSR) around the world. However, the large disparity in the availability of observational data between developed and less developed/developing countries leads to an under-representation of studies on SSR changes in the latter. This is especially true for South America, where few observational studies have investigated the SSR trends and usually only at a local or regional scale. In this study we use data from 34 stations distributed throughout all of the regions of Brazil to present the SSR trends in the first 2 decades of the 21st century and investigate their associated causes. The stations were grouped into eight composites according to their proximity. Our results show that in north and northeast Brazil a strong dimming occurred, with significant contributions from increasing atmospheric absorption, most likely due to anthropogenic emissions, and increasing cloud cover. In the southeast and midwest regions of Brazil, near-zero trends resulted from competing effects of clear-sky processes (attenuation of solar radiation under cloudless conditions) and strong negative trends in cloud cover. In the southern part of the Amazon and in south Brazil a statistically insignificant brightening was observed, with significant contributions from decreasing biomass burning emissions in the former and competing minor contributions in the latter. These results can help deepen our knowledge and understanding of SSR long-term trends and their causes in South America, reducing the under-representation of this continent when compared with regions like Europe. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Design and optimisation of dendrimer-conjugated Bcl-2/xL inhibitor, AZD0466, with improved therapeutic index for cancer therapy

Author

Patterson, Claire M., Balachander, Srividya B., Grant, Iain, Pop-Damkov, Petar, Kelly, Brian, McCoull, William, Parker, Jeremy, Giannis, Michael, Hill, Kathryn J., Gibbons, Francis D., Hennessy, Edward J., Kemmitt, Paul, Harmer, Alexander R., Gales, Sonya, Purbrick, Stuart, Redmond, Sean, Skinner, Matthew, Graham, Lorraine, Secrist, J. Paul, Schuller, Alwin G., Wen, Shenghua, Adam, Ammar, Reimer, Corinne, Cidado, Justin, Wild, Martin, Gangl, Eric, Fawell, Stephen E., Saeh, Jamal, Davies, Barry R., Owen, David J., and Ashford, Marianne B.

Published
2021
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14. Evaluation of radiation schemes in the CMA-MESO model using high time-resolution radiation measurements in China: I. Long-wave radiation.

Author

Yang, Junli, Quan, Weijun, Zhang, Li, Hu, Jianglin, Chen, Qiying, and Wild, Martin

Subjects
ATMOSPHERIC boundary layer, RADIATION measurements, NUMERICAL weather forecasting, CLOUDINESS, RADIATIVE transfer, ATMOSPHERIC turbidity
Abstract

Downward long-wave irradiance (DnLWI) is a variable that directly influences the surface net radiation, which in turn affects weather and climate. Due to the lack of abundant DnLWI observations, numerical weather prediction (NWP) models provide a very effective way to yield the DnLWI. Nevertheless, the reliability of the DnLWI predicted by the NWP models needs the evaluation based on the observations or accurate radiative transfer models. In this study, the DnLWI product of the China Meteorological Administration mesoscale model (CMA-MESO) was extensively validated using long-term high time-resolution (1 min) DnLWI measurements carried out at 42 sites in China. The results showed that the DnLWIs predicted by the CMA-MESO model generally agreed well with the observations, i.e., with a relative mean bias error (rMBE) of –2.0 %, but overestimated them under overcast (3.1 %) and underestimated them under dry (–5.3 %) and cloudless (–5.2 %) conditions. It is also found that the discrepancies in the DnLWI predicted by the CMA-MESO model exhibited spatial and diurnal variations, e.g., the discrepancies were significantly smaller at night than those during the day due to the stable nocturnal boundary layer. According to the results of the partial least squares analysis, the high cloud cover, medium cloud cover, planetary boundary layer height, and integrated cloud ice were the most important factors affecting the accuracy of the DnLWIs predicted by the CMA-MESO model under all sky conditions. By comparing the outputs of the CMA-MESO model and the MODerate resolution atmospheric TRANsmission (MODTRAN) model, it was found that the uncertainties in the DnLWI predicted by the CMA-MESO model mainly arose from an inappropriate consideration of the high and medium clouds under all sky conditions as well as shortcomings in the radiation scheme under cold dry cloudless conditions. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Decadal trends in observed surface solar radiation and their causes in Brazil in the first two decades of the 21st century.

Author

Ferreira Correa, Lucas, Folini, Doris, Chtirkova, Boriana, and Wild, Martin

Abstract

Numerous studies have investigated the long term variability of surface solar radiation (SSR) around the world. However, the large disparity in the availability of observational data between developed and least developed/developing countries leads to an underrepresentation of studies on SSR changes in the latter. This is especially true for South America, where few observational studies have investigated the SSR decadal trends, and usually only at a local or regional scale. In this study we use data from 34 stations distributed throughout all the regions of Brazil to present the decadal SSR decadal trends in the first two decades of the 21st century and investigate their associated causes. The stations were grouped into 8 composites according to their proximity. Our results show that in the North and Northeast Brazil a strong dimming occurred, with significant contributions from increasing atmospheric absorption, most likely due to anthropogenic emissions, and increasing cloud cover. In the Southeast and Midwest regions of Brazil near-zero trends resulted from competing effects of clear-sky processes and strong negative trends in cloud cover. In the South part of the Amazon and in Southern Brazil a statistically insignificant brightening was observed, with significant contribution from decreasing biomass burning emissions in the former and competing minor contributions in the latter. These results can contribute to deepen the knowledge and understanding of SSR decadal trends and their causes in South America, reducing the underrepresentation of this continent when compared to regions like Europe. [ABSTRACT FROM AUTHOR]

Published
2024
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21. A quality-assured dataset of nine radiation components observed at the Shangdianzi regional GAW station in China (2013–2022).

Author

Quan, Weijun, Wang, Zhenfa, Qiao, Lin, Zheng, Xiangdong, Jin, Junli, Li, Yinruo, Yin, Xiaomei, Ma, Zhiqiang, and Wild, Martin

Subjects
ATMOSPHERIC radiation, SOLAR radiation, SOLAR spectra, SPECTRAL irradiance, ATMOSPHERIC composition, RADIATION, DATA loggers
Abstract

The New Baseline Surface Radiation (NBSR) system was established at the Shangdianzi (SDZ) regional Global Atmosphere Watch (GAW) station in 2013 to observe nine broadband radiation components, i.e. the global, direct, diffuse, and upwelling shortwave irradiance (GSWI, DSWI, DifSWI, and UpSWI); the photosynthetically active radiation (PAR); the ultraviolet irradiance (UVAI and UVBI); and the down- and upwelling longwave irradiance (DnLWI and UpLWI). To test the 1 min raw radiometric data, a Hybrid Algorithm for Radiation Data Quality Control (HARDQC) is presented in this study based on well-established methods, together with the solar irradiance dataset and the spectral features of the instrument bands. Subsequently, a NBSR dataset, which consists of radiation data at multiple timescales (i.e. 1 min, hourly, daily, monthly, monthly average hourly, and monthly average daily) over 2013–2022, is established and evaluated. Results show that more than 98.7 % of all radiation components passed the physical possibility test. The percentages of those that passed the extremely rare test are greater than 98.6 % for all radiation components except for the DnLWI (97.1 %). The percentages of those that passed the comparison test are greater than 83.3 % (GSWI), 78.3 % (DSWI), 81.7 % (DifSWI), 93.1 % (UpSWI), 88.9 % (PAR), 95.6 % (UVAI), 96.3 % (UVBI), 99.8 % (DnLWI), and 99.7 % (UpLWI), respectively. Due to data logger faults, removal of the instruments for calibration, and lightning strikes, some apparent data gaps in the upwelling radiation components (January 2015–August 2017) and all radiation components (December 2018; July to September 2021) were detected. Despite the existence of a few imperfections in the NBSR dataset, it is still reliable to apply it in many fields such as the validation of satellite products and numerical models, the investigation of relationships between radiation and atmospheric composition, and the detection of changes in the surface fluxes. The dataset described in this paper is available at 10.1594/PANGAEA.963330 (Quan et al., 2023b). [ABSTRACT FROM AUTHOR]

Published
2024
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26. A quality-assured dataset of nine radiation components observed at the Shangdianzi regional GAW station in China (2013-2022).

Author

Weijun Quan, Zhenfa Wang, Lin Qiao, Xiangdong Zheng, Junli Jin, Yinruo Li, Xiaomei Yin, Zhiqiang Ma, and Wild, Martin

Subjects
SOLAR radiation, ATMOSPHERIC radiation, SOLAR spectra, SPECTRAL irradiance, ATMOSPHERIC composition, RADIATION, DATA loggers
Abstract

A New Baseline Surface Radiation (NBSR) system was established at the Shangdianzi (SDZ) regional Global Atmosphere Watch (GAW) station in 2013 to observe nine broadband radiation components, i.e., the global-, direct-, diffuse-, and upwelling-shortwave irradiance (GSWI, DSWI, DifSWI, and UpSWI) as well as the photosynthetically active radiation (PAR), ultraviolet irradiance (UVAI; UVBI), down- and up-welling long-wave irradiance (DnLWI; UpLWI). To test the 1-min raw radiometric data, a Hybrid Algorithm for Radiation Data Quality Control (HARDQC) is presented in this study based on well-established methods together with the solar irradiance dataset and the spectral features of the instrument bands. Subsequently, an NBSR dataset, which consists of multi-time scale (i.e. 1-min, hourly, daily, monthly, monthly average hourly, and monthly average daily) radiation datasets over 2013-2022, is established and evaluated. Results show that more than 98.7% of all radiation components passed the physical possibility test. The percentages passed the extremely rare test are greater than 98.6% for all radiation components except for the DnLWI (97.1%). The percentages passed the comparison test are greater than 83.3% (GSWI), 78.3% (DSWI), 81.7% (DifSWI), 93.1% (UpSWI), 88.9% (PARI), 95.6% (UVAI), 96.3% (UVBI), 99.8% (DnLWI), and 99.7% (UpLWI), respectively. Due to data logger faults, removal of the instruments for calibration, and lightning strokes, some apparent data gaps in the upwelling radiation components (January 2015-August 2017) and all radiation components (December 2018; July to September 2021) were detected. Despite the existence of a few imperfections in the NBSR dataset, it is still reliable to apply in many fields such as the validation of satellite products and numerical models, investigation of relationships between radiation and atmospheric composition, and the detection of changes in the surface fluxes. [ABSTRACT FROM AUTHOR]

Published
2023
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27. The onset of solar dimming and brightening: The role of internal variability

Author

Chtirkova, Boriana, Folini, Doris, Ferreira Correa, Lucas, and Wild, Martin

Abstract

Decadal changes in observed surface solar radiation (SSR), coined dimming and brightening, are of interest for a number of reasons ranging from energy balance considerations to long-term planning of photovoltaic energy production. Decadal trends in anthropogenic aerosol have been advocated as one of the main drivers for the observed SSR phenomenon. Given the historical emission scenario, coupled climate models seem, however, unable to reproduce the observed SSR trends: their magnitudes, onset times, and lengths. In order to get more insight into these discrepancies, we analyse data from the historical simulations within the Coupled Model Intercomparison Project - Phase 6 (CMIP6). For any single model, we compare different ensemble members, which by design are different realizations (initial conditions) with identical forcings (boundary conditions). Thus any differences within the ensemble members are due to internal variability. We examine aerosol emissions, aerosol optical thickness (AOD), all-sky and clear-sky SSR on a per grid box level. It is intriguing to find that given identical emission scenarios, the onsets of the strongest AOD trends differ across ensemble members, as do the onsets of strongest SSR trends, differing among ensemble members by 10 years or more. Another highlight of the study is that SSR (all-sky and clear-sky) across different ensemble members varies less in certain locations (e.g. Europe and N. Asia) and greatly in others (Australia, Africa, S. America), possibly due to stronger forcing and less natural variability in the former regions, while the opposite in the latter regions., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

28. Report of IRC Working Group Global Energy Balance: Downward longwave radiation - a critical component of the Global Energy Balance

Author

Wild, Martin

Abstract

This working group focuses on the assessment of the magnitudes and uncertainties of the components of the global energy balance, their decadal changes and underlying causes as well as their significance for climate change.While the radiative fluxes at the top of atmosphere can be accurately measured from satellites, the energy fluxes within the climate system and at the Earth surface are less well determined. Accordingly, estimates of the surface energy balance components still substantially differ even on a global mean basis in climate models, reanalyses and satellite-derived products. A focus is therefore on the surface energy flux components, with particular emphasis on the surface downward longwave radiation (DLR). DLR is a critical component in the context of climate change, as it is most immediately affected by the increasing levels of atmospheric greenhouse gases. DLR is also expected to undergo the largest changes amongst all energy balance components over the coming decades. CMIP6 models project a multimodel-mean increase in DLR of 35 Wm-2 until 2100 compared to preindustrial levels under the fossil-fuel driven scenario SSP585, while still 20 Wm-2 under the moderate-mitigation scenario SSP245. Surface observations support an increase in downward longwave radiation by around 1-2 Wm-2/decade. The surface observations also allowed to identify a tendency for underestimation of DLR in generations of climate models. Over the history of climate model development, the DLR was gradually adjusted upwards, ultimately by 15 Wm-2, which helped to remediate this underestimation. Still, DLR remains too low in some of the models and reanalyses., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

29. Internal variability in Earth's energy balance

Author

Folini, Doris, Chtirkova, Boriana, Ferreira Correa, Lucas, and Wild, Martin

Abstract

Various studies have examined internal variability of annual mean surface solar radiation. The variability was statistically characterized and a close link with decadal scale trends was demonstrated. The latter were shown to regionally bear an imprint from low frequency modes of sea surface temperature variability. Here we extend this analysis to further components of Earth's energy balance., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

30. Aerosol sensitivity simulations over East Asia in a convection-permitting climate model (2/2)

Author

Li, Shuping, Søreland, Lund Silje, Wild, Martin, and Schär, Christoph

Abstract

Decade-long (2001-2010) aerosol sensitivity simulations over East Asia are performed based on thenon-hydrostatic limited-area COSMO model in its GPU-enabled version for both numericalweather prediction and climate modeling. The dataset has been used to evaluatethe performance of convection-parameterizing (12 km)and convection-permitting (4.4 km) approaches over East Asia and investigate the impacts ofperturbed sulfate and black carbon aerosols on radiation, air temperature, and precipitation in the simulations with explicit deep convection. 1.cosmo_eas04_BCx03.tar.gz Aerosol sensitivity simulationat 4.4km horizontal grid spacing with reducing black carbon aerosols by a factor of 1/3. 2.cosmo_eas04_BCx3.tar.gz Aerosol sensitivity simulationat 4.4km horizontal grid spacing with increasingblack carbon aerosols by a factor of 3. 3.cosmo_eas04_REF.tar.gz Reference simulation at 4.4km horizontal grid spacing with default AeroCom aerosol dataset (including domain information). 4.cosmo_eas04_SUx03.tar.gz Aerosol sensitivity simulationat 4.4km horizontal grid spacing with reducing sulfate aerosols by a factor of 1/3. 5.cosmo_eas04_SUx3.tar.gz Aerosol sensitivity simulationat 4.4km horizontal grid spacing with increasing sulfate aerosols by a factor of 3.

Published
2022
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31. Aerosol sensitivity simulations over East Asia in a convection-permitting climate model (1/2)

Author

Li, Shuping, Søreland, Lund Silje, Wild, Martin, and Schär, Christoph

Abstract

Decade-long (2001-2010) aerosol sensitivity simulations over East Asia are performed based on thenon-hydrostatic limited-area COSMO model in its GPU-enabled version for both numericalweather prediction and climate modeling. The dataset has been used to evaluatethe performance of convection-parameterizing (12 km)and convection-permitting (4.4 km) approaches over East Asia and investigate the impacts ofperturbed sulfate and black carbon aerosols on radiation, air temperature, and precipitation in the simulations with explicit deep convection. 1.cosmo_eas11_BCx03.tar.gz Aerosol sensitivity simulationat 12 km horizontal grid spacing with reducing black carbon aerosols by a factor of 1/3. 2.cosmo_eas11_BCx3.tar.gz Aerosol sensitivity simulationat 12 km horizontal grid spacing with increasingblack carbon aerosols by a factor of 3. 3.cosmo_eas11_REF.tar.gz Reference simulation at12 km horizontal grid spacing with default AeroCom aerosol dataset (including domain information). 4.cosmo_eas11_SUx03.tar.gz Aerosol sensitivity simulationat 12 km horizontal grid spacing with reducing sulfate aerosols by a factor of 1/3. 5.cosmo_eas11_SUx3.tar.gz Aerosol sensitivity simulationat 12 km horizontal grid spacing with increasing sulfate aerosols by a factor of 3. &nbsp

Published
2022
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37. Robust evidence for reversal of the trend in aerosol effective climate forcing

Author

Quaas, Johannes, primary, Jia, Hailing, additional, Smith, Chris, additional, Albright, Anna Lea, additional, Aas, Wenche, additional, Bellouin, Nicolas, additional, Boucher, Olivier, additional, Doutriaux-Boucher, Marie, additional, Forster, Piers M., additional, Grosvenor, Daniel, additional, Jenkins, Stuart, additional, Klimont, Zbigniew, additional, Loeb, Norman G., additional, Ma, Xiaoyan, additional, Naik, Vaishali, additional, Paulot, Fabien, additional, Stier, Philip, additional, Wild, Martin, additional, Myhre, Gunnar, additional, and Schulz, Michael, additional

Published
2022
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41. On the Contribution of Aerosols and Clouds to Global Dimming and Brightening Using a Radiative Transfer Model, ISCCP-H Cloud and MERRA-2 Aerosol Optical Properties.

Author

Stamatis, Michael, Hatzianastassiou, Nikolaos, Korras-Carraca, Marios-Bruno, Matsoukas, Christos, Wild, Martin, and Vardavas, Ilias

Subjects
ATMOSPHERIC aerosols, RADIATIVE transfer, CLOUD computing
Abstract

The interdecadal changes of the incident solar radiation at the Earth's surface (SSR) are mainly driven by changes in clouds and aerosols. In order to investigate their contribution to the SSR changes (global dimming and brightening or GDB), the FORTH radiative transfer model (RTM) is used to compute the SSR fluxes. The cloud input data were taken from satellite observations of ISCCP-H, while aerosols and meteorological data were taken from the MERRA-2 reanalysis dataset. The RTM operates on a monthly basis and in 0.5° x 0.625° latitude-longitude spatial resolution. The GDB was also computed keeping constant at their initial 1984 values, each input parameter that was examined, resulting in a GDB with the 'frozen' parameter. The contribution of each parameter to the GDB is defined as the subtraction of the frozen GDB from the base-run GDB, and the positive/negative values of the contribution indicate that the interdecadal variability of the examined parameter increased/decreased the SSR. The aerosol optical depth (AOD) produced a dimming in India, Amazonia, and S. China, whereas it induced a brightening in Europe and Mexico. On the other hand, the total cloud cover (TCC) changes caused a dimming over the Arctic, Australia, and the South Ocean against a brightening in Europe, Mexico, the Middle East, and South America. The global mean contribution of changing AOD is 0.37 W/m², and for TCC, it is 4.7 W/m², indicating that globally, the counteraction of cloud cover to the overall global dimming is larger. Opposite contributions to GDB from AOD and TCC may occur over specific regions, highlighting the complexity of the causes of the GDB phenomenon. [ABSTRACT FROM AUTHOR]

Published
2023
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43. Inversione di tendenza clima e biodiversità. Il Parlamento incontra la scienza

Author

Adler, Carolina, Bacher, Sven, Battiston, Stefano, Bernauer, Thomas, Boch, Steffen, Boillat, Sebastien, Brooks, Thomas, Cissé, Guéladio, Fischer, Erich, Fischer, Markus, Fischlin, Andreas, Fröhlicher, Thomas, Guisan, Antoine, Huggel, Christian, Jaccard, Samuel, Krug, Cornelia, Muccione, Veruska, Mukerji, Rupa, Neu, Urs, Patt, Anthony, Kasper, Gian, Schläpfer, Martin, Seneviratne, Sonia, Spehn, Eva, Steinberger, Julia, Wild, Martin, and Zimmermann, Niklaus

Abstract

Su invito della presidente del Consiglio nazionale Irène Kälin e del presidente del Consiglio degli Stati Thomas Hefti, il 2 maggio 2022 il Parlamento ha discusso con i ricercatori le sfide della crisi del clima e della biodiversità. I politici hanno scambiato opinioni con scienziati che lavorano in Svizzera e con gli autori dei rapporti del Gruppo intergovernativo sui cambiamenti climatici e del Gruppo intergovernativo sulla biodiversità., Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022). Inversione di tendenza clima e biodiversità. Il Parlamento incontra la scienza. Swiss Academies Communications 17 (6)

Published
2022
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44. Trendwende Klima und Biodiversität: Parlament trifft Wissenschaft

Author

Adler, Carolina, Bacher, Sven, Battiston, Stefano, Bernauer, Thomas, Boch, Steffen, Boillat, Sebastien, Brooks, Thomas, Cissé, Guéladio, Fischer, Erich, Fischer, Markus, Fischlin, Andreas, Fröhlicher, Thomas, Guisan, Antoine, Huggel, Christian, Jaccard, Samuel, Krug, Cornelia, Muccione, Veruska, Mukerji, Rupa, Neu, Urs, Patt, Anthony, Plattner, Gian-Kasper, Schläpfer, Martin, Seneviratne, Sonia, Spehn, Eva, Steinberger, Julia, Wild, Martin, Zimmermann, Niklaus, Guisan, Antoine, Huggel, Christian, Seneviratne, Sonia I., and Steinberger, Julia

Abstract

Auf Einladung der Nationalratspräsidentin Irène Kälin und des Ständeratspräsidenten Thomas Hefti diskutierte das Parlament am 2. Mai mit Forschenden die Herausforderungen der Klima- und Biodiversitätskrise. Die Politikerinnen und Politiker tauschten sich mit den in der Schweiz tätigen Wissenschaftlern und Verfasserinnen der Berichte des Weltklimarates und des Weltbiodiversitätsrates aus., Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022) Trendwende Klima und Biodiversität. Parlament trifft Wissenschaft Swiss Academies Communications 17 (6).

Published
2022
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45. Inverser la tendance : climat et biodiversité. Rencontre entre le Parlement et les scientifiques

Author

Adler, Carolina, Bacher, Sven, Battiston, Stefano, Bernauer, Thomas, Boch, Steffen, Boillat, Sebastien, Brooks, Thomas, Cissé, Guéladio, Fischer, Erich, Fischer, Markus, Fischlin, Andreas, Fröhlicher, Thomas, Guisan, Antoine, Huggel, Christian, Jaccard, Samuel, Krug, Cornelia, Muccione, Veruska, Mukerji, Rupa, Neu, Urs, Patt, Anthony, Plattner, Gian-Kasper, Schläpfer, Martin, Seneviratne, Sonia, Spehn, Eva, Steinberger, Julia, Wild, Martin, and Zimmermann, Niklaus

Abstract

Irène Kälin, présidente du Conseil national, et Thomas Hefti, président du Conseil des Etats, ont convié les scientifiques et le Parlement à une séance de discussion sur la crise climatique et la perte de la biodiversité qui aura lieu le 2 mai 2022. En vue de cet événement, les auteur·e·s suisses du 6e rapport d’évaluation du groupe d’expert·e·s intergouvernemental sur l’évolution du climat (GIEC) et des rapports de la plateforme intergouvernementale scientifique et politique sur la biodiversité et les services écosystémiques (IPBES) ont compilé les principales constations pour la Suisse., Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022) Inverser la tendance : climat et biodiversité. Rencontre entre le Parlement et les scientifiques. Swiss Academies Communications 17 (6).

Published
2022
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46. Meteorologically-Informed Spatial Planning of European PV Deployment to Reduce Multiday Generation Variability

Author

Mühlemann, Dirk (author), Folini, Doris (author), Pfenninger, Stefan (author), Wild, Martin (author), Wohland, Jan (author), Mühlemann, Dirk (author), Folini, Doris (author), Pfenninger, Stefan (author), Wild, Martin (author), and Wohland, Jan (author)

Abstract

Renewable generation variability over multiple days is a key challenge in decarbonizing the European power system. Weather regimes are one way to quantify this variability, but so far, their applications to energy research have focused on wind power generation in winter. However, the projected growth of solar photovoltaic (PV) capacity implies that its absolute variability across the continent will grow substantially. Here we combine weather regimes based on ERA5 reanalysis data with country-specific capacity factors to investigate multiday PV generation variability in Europe. With current installed capacity (131 GW), total PV production in Europe (52.3 GW) varies by 0.9 GW on average, with a maximum change of 3.0 GW, upon transition from one weather regime to another. Using projected PV capacity for 2050 (1.94 TW), variability would rise to 13.9 and 43.8 GW. We present optimized spatial distributions of capacity additions in three scenarios that substantially reduce variability by up to 40%. One of them ascertains a large local PV production, thereby minimizing the need for long-range power transmission while still reducing variability by about 30%, highlighting that optimized siting and local generation can be reconciled. Our results emphasize the value of leveraging climate information in decarbonizing power systems., Energy & Industry

Published
2022
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47. Vegetation type is an important predictor of the arctic summer land surface energy budget

Author

Environmental Sciences, Afd Marine and Atmospheric Research, Spatial Ecology and Global Change, Sub Algemeen Marine & Atmospheric Res, Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, Chambers, Scott D., Environmental Sciences, Afd Marine and Atmospheric Research, Spatial Ecology and Global Change, Sub Algemeen Marine & Atmospheric Res, Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, and Chambers, Scott D.

Published
2022

48. Observations and Implications of Diurnal Climatology and Trends in Direct and Diffuse Solar Radiation Over China

Author

Wang, Yawen, Zhang, Jiahua, Trentmann, Jörg, Fiedler, Stephanie, Yang, Su, Sanchez‐Lorenzo, Arturo, Tanaka, Katsumasa, Yuan, Wenping, Wild, Martin, Wang, Yawen, Zhang, Jiahua, Trentmann, Jörg, Fiedler, Stephanie, Yang, Su, Sanchez‐Lorenzo, Arturo, Tanaka, Katsumasa, Yuan, Wenping, and Wild, Martin

Abstract

Solar radiation received at the Earth's surface (Rs) is comprised of two components, the direct radiation (Rd) and the diffuse radiation (Rf). Rd, the direct beam from the sun, is essential for concentrated solar power generation. Rf, scattered by atmospheric molecules, aerosols, or cloud droplets, has a fertilization effect on plant photosynthesis. But how Rd and Rf change diurnally is largely unknown owing to the lack of long-term measurements. Taking advantage of 22 years of homogeneous hourly surface observations over China, this study documents the climatological means and evolutions in the diurnal cycles of Rd and Rf since 1993, with an emphasis on their implications for solar power and agricultural production. Over the solar energy resource region, we observe a loss of Rd which is relatively large near sunrise and sunset at low solar elevation angles when the sunrays pass through the atmosphere on a longer pathway. However, the concentrated Rd energy covering an average 10-hr period around noon during a day is relatively unaffected. Over the agricultural crop resource region, the large amounts of clouds and aerosols scattering more of the incoming light result in Rf taking the main proportion of Rs during the whole day. Rf resources and their fertilization effect in the main crop region of China further enhances since 1993 over almost all hours of the day. Key Points: - The loss of direct radiation over China since 1993 is relatively large at sunrise and sunset with little effect on solar power generation - The diffuse component dominates solar radiation normally near sunrise and sunset, but for the whole day over the main sown area of China - The diffuse fraction is further enhanced in the main sown area of China over almost all hours of the day since 1993

Published
2022
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49. Robust evidence for reversal of the trend in aerosol effective climate forcing

Author

Quaas, Johannes, Jia, Hailing, Smith, Chris, Albright, Anna Lea, Aas, Wenche, Bellouin, Nicolas, Boucher, Olivier, Doutriaux-Boucher, Marie, Forster, Piers M., Grosvenor, Daniel, Jenkins, Stuart, Klimont, Zbigniew, Loeb, Norman G., Ma, Xiaoyan, Naik, Vaishali, Paulot, Fabien, Stier, Philip, Wild, Martin, Myhre, Gunnar, Schulz, Michael, Quaas, Johannes, Jia, Hailing, Smith, Chris, Albright, Anna Lea, Aas, Wenche, Bellouin, Nicolas, Boucher, Olivier, Doutriaux-Boucher, Marie, Forster, Piers M., Grosvenor, Daniel, Jenkins, Stuart, Klimont, Zbigniew, Loeb, Norman G., Ma, Xiaoyan, Naik, Vaishali, Paulot, Fabien, Stier, Philip, Wild, Martin, Myhre, Gunnar, and Schulz, Michael

Abstract

Anthropogenic aerosols exert a cooling influence that offsets part of the greenhouse gas warming. Due to their short tropospheric lifetime of only several days, the aerosol forcing responds quickly to emissions. Here, we present and discuss the evolution of the aerosol forcing since 2000. There are multiple lines of evidence that allow us to robustly conclude that the anthropogenic aerosol effective radiative forcing (ERF) – both aerosol– radiation interactions (ERFari) and aerosol–cloud interactions (ERFaci) – has become less negative globally, i.e. the trend in aerosol effective radiative forcing changed sign from negative to positive. Bottom-up inventories show that anthropogenic primary aerosol and aerosol precursor emissions declined in most regions of the world; observations related to aerosol burden show declining trends, in particular of the fine-mode particles that make up most of the anthropogenic aerosols; satellite retrievals of cloud droplet numbers show trends in regions with aerosol declines that are consistent with these in sign, as do observations of top-of-atmosphere radiation. Climate model results, including a revised set that is constrained by observations of the ocean heat content evolution show a consistent sign and magnitude for a positive forcing relative to the year 2000 due to reduced aerosol effects. This reduction leads to an acceleration of the forcing of climate change, i.e. an increase in forcing by 0.1 to 0.3 W m−2 , up to 12 % of the total climate forcing in 2019 compared to 1750 according to the Intergovernmental Panel on Climate Change (IPCC).

Published
2022

50. Vegetation type is an important predictor of the arctic summer land surface energy budget

Author

Oehri, Jacqueline; https://orcid.org/0000-0002-2981-9402, Schaepman-Strub, Gabriela; https://orcid.org/0000-0002-4069-1884, Kim, Jin-Soo; https://orcid.org/0000-0003-0631-2294, Grysko, Raleigh; https://orcid.org/0000-0002-5789-096X, et al, Zemlianskii, Vitalii, Reji Chacko, Merin, Plekhanova, Elena, Wild, Martin, Oehri, Jacqueline; https://orcid.org/0000-0002-2981-9402, Schaepman-Strub, Gabriela; https://orcid.org/0000-0002-4069-1884, Kim, Jin-Soo; https://orcid.org/0000-0003-0631-2294, Grysko, Raleigh; https://orcid.org/0000-0002-5789-096X, et al, Zemlianskii, Vitalii, Reji Chacko, Merin, Plekhanova, Elena, and Wild, Martin

Abstract

Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994–2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm−2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.

Published
2022

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