Abstract ID: 3.11516 | Accepted as Talk | Talk/Oral | TBA | TBA

The snow cover in the Upper Euphrates Basin, the headwater of the transboundary Euphrates River located in the mountainous region of Eastern Türkiye, has changed in recent decades due to warming. Particularly, rising temperatures shift the timing of snowmelt and shorten the snow season. Since the snowmelt is crucial for water resources and energy production in the basin, changes in the snow cover pattern increase the basin’s vulnerability to climate change. In this study, we first investigated the changes in snow depth and snow cover during the snow season from November to April in the Upper Euphrates Basin for the 1985–2021 period by using the Copernicus European Regional Reanalysis for Land (CERRA-Land) dataset at 5.5 km horizontal resolution. Following that, we performed convection-permitting climate simulations at a 3 km horizontal resolution for the 2005–2014 reference and 2041–2050, 2061–2070, and 2091-2100 future periods to reveal the changes in temperature extremes and land-atmosphere interactions due to reduced snow cover in detail over the basin. To this end, we downscaled the MPI-ESM1.2-HR simulations under the SSP3-7.0 scenario using the WRF model. The analyses of CERRA-Land indicate that snow cover has diminished significantly in November, with levels remaining below 5% during the 2012–2021 period at grid points between 1.000 and 1.500 meters in altitude. Also, future climate simulations indicate an earlier snowmelt in spring, decreasing the snow cover by about 20%, and the surface albedo by about 10% in the same elevation range due to sudden warming in March across the study area. Moreover, trend analysis of CERRA-Land shows that the maximum snow depth during March and April decreases up to 30 cm/decade. The outcomes of this study emphasize the earlier snowmelt, the retreat of snow cover, and the shortening of the snow season in historical and future periods in the Upper Euphrates Basin.