Impacts of Historical Land Use/Cover Change (1980–2015) on Summer Climate in the Aral Sea Region

In the Aral Sea region, significant land use/cover change (LUCC) occurred in the past 50 years, especially the shrinking of Aral Sea due to unreasonable usage of water resources under intensified agricultural activities. However, to date, regional climatic feedbacks on fine-scale exerted by such LUCC in Central Asia have not been studied clearly. In this study, ALARO-SURFEX regional climate model was used to perform climate simulations under different underlying surface scenarios with 4 km spatial resolution to explore the impacts of historical LUCC on summer climate during 1980-2015. Our results show that compared to default land surface conditions, the modified ones improved the model's ability in simulating temperature, precipitation, and surface energy fluxes. During the period 1980-2015, LUCC accelerated the warming trend, reduced the summer precipitation and altered allocation of surface energy fluxes. Exposed dry bottom of Aral Sea has undergone the most conspicuous warming, which caused increase of the 2 m maximum temperature, average temperature, and diurnal temperature range by 2.56 +/- 0.88 degrees C, 1.04 +/- 0.53 degrees C, and 3.42 +/- 1.10 degrees C, respectively, while minimum temperature decrease by 1.14 +/- 0.56 degrees C. The summer precipitation (mainly convective precipitation) decreased by about 2.33 mm overlay the exposed dry bottom of Aral Sea and approximately 400 km buffer region in its eastern side. Additionally, the energy balance changed as follows: -47.9, 50.19, -78.67, and -23.72 W m(-2) for net radiation, sensible heat, latent heat, and soil heat, respectively. Quantified contribution of LUCC on regional climate provides useful information for developing mitigation and adaption strategies under the global warming threat.