Simulated mean climate response to Caspian Sea area change using the Community Earth System Model (CESM1.2.2)

The Caspian Sea (CS) is the largest inland lake in the world. Large variations in sea level and surface area occurred in the past and are projected for the future. The potential impacts on regional and large-scale hydroclimate are not well understood. Here, we examine the impact of CS area on climate within its catchment and in the wider northern hemisphere. The Community Earth System Model (CESM1.2.2) is used to simulate the climate of four scenarios: (1) larger than present CS area, (2) current area, (3) smaller than present area, and (4) no-CS scenario. The results reveal large changes in the regional atmospheric water budget. Evaporation (E) over the sea increases with increasing area, while precipitation (P) increases over the south-west CS with increasing area. P-E over the CS catchment decreases as CS surface area increases, indicating a dominant negative lake-evaporation feedback. A larger CS area reduces summer surface air temperatures and increases winter temperatures. […]

里海（CS）乃全球最大的内陆湖泊。其水位与表面积在过去经历了显著变化，且未来亦预计将发生类似情况。对区域及大规模水气候可能产生的影响尚缺乏深入了解。本研究旨在探讨里海面积对其流域及其更广阔的北半球气候的影响。本研究采用社区地球系统模型（CESM1.2.2）对四种情景下的气候进行模拟：（1）里海面积大于当前面积，（2）当前面积，（3）里海面积小于当前面积，以及（4）无里海情景。模拟结果显示，区域大气水循环预算发生了显著变化。随着里海面积的扩大，蒸发量（E）增加，而在里海西南部，降水量（P）亦随面积扩大而增加。随着里海面积的增大，其流域内的降水量与蒸发量之差（P-E）减少，表明湖泊蒸发对气候具有显著的负反馈作用。更大的里海面积导致夏季地表空气温度降低，而冬季温度升高。