North—south differentiation on the spatiotemporal variations of potential evaporation in Tibetan Plateau
摘要
Investigating the spatial pattern and temporal variations of potential evaporation is of great importance in understanding the variations of the actual evaporation and water balance in the Tibetan Plateau.Several hydroclimatic and environmental variables display distinct spatial and temporal patterns in the Tibetan Plateau, but the patterns in the potential evaporation remain unclear.In this study, the potential evaporation from 1980 to 2015 was calculated by the Penman equation using the data of 312 stations in the Tibetan Plateau and its surrounding areas.The potential evaporation and its radiation and aerodynamic terms show non-monotonic spatiotemporal variations, but the variations differ between the north and south of the Tibetan Plateau.The mean annual potential evaporation is bound by 32°30'N and shows a "V" shape pattern with latitude: decreasing with latitude in the south region and increasing with latitude in the north.The annual potential evaporation and its radiation term and aerodynamic term all show non-monotonic changes with 1999 as the turning point but the trends substantially differ between the north and south regions.The results reveal the distinct spatial and temporal patterns of the impacts of the westerlies and the Indian monsoon on the potential evaporation.