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Yayın Spatial extent of precipitation events: when big is getting bigger(Springer Science and Business Media Deutschland GmbH, 2022-03) Matte, Dominic; Christensen, Jens Hesselbjerg; Öztürk, TuğbaUsing a sub-selection of regional climate models at 0.11 degrees (approximate to 12 km) grid resolution from the EURO-CORDEX ensemble, we investigate how the spatial extent of areas associated with the most intensive daily precipitation events changes as a consequence of global warming. We address this by analysing three different warming levels: 1 degrees C, 2 degrees C and 3 degrees C. We find that not only does the intensity of such events increase, but their size will also change as a function of the warming: larger systems becomes more frequent and larger, while systems of lesser extent are reduced in numbers.Yayın Robustness of future atmospheric circulation changes over the EURO-CORDEX domain(Springer Science and Business Media Deutschland GmbH, 2022-09) Öztürk, Tuğba; Matte, Dominic; Christensen, Jens HesselbjergEuropean climate is associated with variability and changes in the mid-latitude atmospheric circulation. In this study, we aim to investigate potential future change in circulation over Europe by using the EURO-CORDEX regional climate projections at 0.11° grid mesh. In particular, we analyze future change in 500-hPa geopotential height (Gph), 500-hPa wind speed and mean sea level pressure (MSLP) addressing different warming levels of 1 °C, 2 °C and 3 °C, respectively. Simple scaling with the global mean temperature change is applied to the regional climate projections for monthly mean 500-hPa Gph and 500-hPa wind speed. Results from the ensemble mean of individual models show a robust increase in 500-hPa Gph and MSLP in winter over Mediterranean and Central Europe, indicating an intensification of anticyclonic circulation. This circulation change emerges robustly in most simulations within the coming decade. There are also enhanced westerlies which transport warm and moist air to the Mediterranean and Central Europe in winter and spring. It is also clear that, models showing different responses to circulation depend very much on the global climate model ensemble member in which they are nested. For all seasons, particularly autumn, the ensemble mean is much more correlated with the end of the century than most of the individual models. In general, the emergence of a scaled pattern appears rather quickly.Yayın Global exposure of population and land-use to meteorological droughts under different warming levels and SSPs: A CORDEX based study(John Wiley and Sons Ltd, 2021-12) Spinoni, Jonathan; Barbosa, Paulo; Bucchignani, Edoardo; Cassano, John; Cavazos, Tereza; Cescatti, Alessandro; Christensen, Jens Hesselbjerg; Christensen, Ole Bossing; Coppola, Erika; Evans, Jason; Forzieri, Giovanni; Geyer, Beate; Giorgi, Filippo; Jacob, Daniela; Katzfey, Jack; Koenigk, Torben; Laprise, Rene; Lennard, Christopher John; Kurnaz, Mehmet Levent; Li, Delei; Llopart, Marta; McCormick, Niall; Naumann, Gustavo; Nikulin, Grigory; Öztürk, Tuğba; Panitz, Hans-Jurgen; da Rocha, Rosmeri Porfirio; Solman, Silvina Alicia; Syktus, Jozef; Tangang, Fredolin; Teichmann, Claas; Vautard, Robert; Vogt, Jurgen Valentin; Winger, Katja; Zittis, George; Dosio, AlessandroGlobal warming is likely to cause a progressive drought increase in some regions, but how population and natural resources will be affected is still underexplored. This study focuses on global population and land-use (forests, croplands, pastures) exposure to meteorological drought hazard in the 21st century, expressed as frequency and severity of drought events. As input, we use a large ensemble of climate simulations from the Coordinated Regional Climate Downscaling Experiment, population projections from the NASA-SEDAC dataset, and land-use projections from the Land-Use Harmonization 2 project for 1981-2100. The exposure to drought hazard is presented for five SSPs (SSP1-SSP5) at four Global Warming Levels (GWLs, from 1.5 to 4 degrees C). Results show that considering only Standardized Precipitation Index (SPI; based on precipitation), the combination SSP3-GWL4 projects the largest fraction of the global population (14%) to experience an increase in drought frequency and severity (vs. 1981-2010), with this value increasing to 60% if temperature is considered (indirectly included in the Standardized Precipitation-Evapotranspiration Index, SPEI). With SPEI, considering the highest GWL for each SSP, 8 (for SSP2, SSP4, and SSP5) and 11 (SSP3) billion people, that is, more than 90%, will be affected by at least one unprecedented drought. For SSP5 (fossil-fuelled development) at GWL 4 degrees C, approximately 2 center dot 10(6) km(2) of forests and croplands (respectively, 6 and 11%) and 1.5 center dot 10(6) km(2) of pastures (19%) will be exposed to increased drought frequency and severity according to SPI, but for SPEI, this extent will rise to 17 center dot 10(6) km(2) of forests (49%), 6 center dot 10(6) km(2) of pastures (78%), and 12 center dot 10(6) km(2) of croplands (67%), with mid-latitudes being the most affected areas. The projected likely increase of drought frequency and severity significantly increases population and land-use exposure to drought, even at low GWLs, thus extensive mitigation and adaptation efforts are needed to avoid the most severe impacts of climate change.
