The new high resolution climate projections dataset DRIAS-2020 over France
Authors: Soubeyroux Jean-Michel , Bernus Sebastien , Corre Lola , Gouget Viviane , Kerdoncuff Maryvonne , Somot Samuel , Tocquer Flore 
Published: June 2021

&lt;p&gt;&lt;span&gt;This &lt;/span&gt;&lt;span&gt;communication will &lt;/span&gt;&lt;span&gt;present the &lt;/span&gt;&lt;span&gt;new &lt;/span&gt;&lt;span&gt;high resolution&lt;/span&gt;&lt;span&gt; climate &lt;/span&gt;&lt;span&gt;dataset&lt;/span&gt;&lt;span&gt; over France &lt;/span&gt;&lt;span&gt;named DRIAS-2020, available&lt;/span&gt;&lt;span&gt; on the &lt;/span&gt;&lt;span&gt;French &lt;/span&gt;&lt;span&gt;partnership &lt;/span&gt;&lt;span&gt;national &lt;/span&gt;&lt;span&gt;climate service &lt;/span&gt;&lt;span&gt;DRIAS&lt;/span&gt;&lt;span&gt; (Meteo-France, IPSL and CERFACS) &lt;/span&gt;&lt;span&gt;and &lt;/span&gt;&lt;span&gt;the associated&lt;/span&gt; &lt;span&gt;report&lt;/span&gt; &lt;span&gt;published on January 2021.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;As for the previous &lt;/span&gt;&lt;span&gt;publication in&lt;/span&gt;&lt;span&gt; 2014, the climate projections are based on the Euro-Cordex ensemble, whose contents have been greatly enriched over the past six years. Different selection criteria were defined to build a robust and synthetic set (8 to 12 simulations for each of the three scenarios RCP2.6, RCP4.5 and RCP8.5) that best represents the uncertainties of climate change in France. The selected climate simulations were corrected by the new Adamont method &lt;/span&gt;&lt;span&gt;(Verfaillie et al, 2017) applied to the SAFRAN reanalysis at 8km resolution over France&lt;/span&gt;&lt;span&gt;. This method provides the DRIAS portal &lt;/span&gt;&lt;span&gt;(www.drias-climat.fr) &lt;/span&gt;&lt;span&gt;with a new coherent dataset of several meteorological variables (temperature, precipitation, snow, humidity, wind, radiation). &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The availability of this dataset was joined &lt;/span&gt;&lt;span&gt;with&lt;/span&gt;&lt;span&gt; a scientific report &amp;#8220;DRIAS-2020&amp;#8221; analysing the expected climate change in France during the 21&lt;/span&gt;&lt;sup&gt;&lt;span&gt;st&lt;/span&gt;&lt;/sup&gt;&lt;span&gt; century.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The &lt;/span&gt;&lt;span&gt;mean&lt;/span&gt;&lt;span&gt; temperature is &lt;/span&gt;&lt;span&gt;increasing&lt;/span&gt;&lt;span&gt; for all three scenarios, with a continuous rise until the end of the century (period 2071-2100) for RCP4.5 and RCP8.5, with median values reaching +2.1&amp;#176;C and +3.9&amp;#176;C respectively. This warming, more marked in the summer, presents a geographical variability with a stronger increase in the east of the country. This change in temperature is also reflected in the extremes, with a &lt;/span&gt;&lt;span&gt;dramatic&lt;/span&gt; &lt;span&gt;rise&lt;/span&gt;&lt;span&gt; in the number of heat wave days in all three scenarios. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The evolution of annual precipitation&lt;/span&gt;&lt;span&gt;, stable or slightly increasing depending on the horizons and scenarios, is accompanied by model uncertainty, which can reverse the sign of the trend. This evolution is subject to seasonal (increase in winter, decrease in summer) and geographical variations (increase in the northern half and decrease in &lt;/span&gt;&lt;span&gt;some&lt;/span&gt;&lt;span&gt; regions of the &lt;/span&gt;&lt;span&gt;South&lt;/span&gt;&lt;span&gt;). The evolution of extreme precipitation and summer droughts also presents strong uncertainties.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;These data are intended to be widely used in France for all impact or adaptation studies&lt;/span&gt; &lt;span&gt;such as &lt;/span&gt;&lt;span&gt;already done for &lt;/span&gt;&lt;span&gt;snow cover &lt;/span&gt;&lt;span&gt;(ClimSnow) &lt;/span&gt;&lt;span&gt;or &lt;/span&gt;&lt;span&gt;in progress for &lt;/span&gt;&lt;span&gt;water resource (National Explore2 project).&lt;/span&gt;&lt;/p&gt;