Climate Change And Its Impact On Potential Evapotranspiration In The Tibetan Plateau

The Tibetan plateau is a sensitive area to climate change,so it is of great significance to study its climate and potential evapotranspiration changes of the region.This paper takes the Tibetan plateau as the research object,interpolates station meteorological data to 8km×8km grid by inverse distance weighting method,calculates potential evapotranspiration by Penman-Monteith formula,analyzes the characteristics of climate spatio-temporal change and the trend of climate zone change in recent 60 years,and tests the significance of climate factor change by Mann-Kendall.The sensitivity of potential evapotranspiration of Tibetan plateau to the change of climate factors and the contribution rate of climate factors to potential evapotranspiration are quantitatively analyzed by using partial differential method on the annual scale.According to the research,the daily average,daily maximum and daily minimum temperature of the Tibetan plateau increased significantly from 1961 to 2017,and increased by 0.33?,0.28?and 0.43 C every 10 years,respectively.The temperature increase range increased from south to north,and the daily minimum temperature increased more than the daily maximum temperature.Sunshine hours decreased significantly(-15.96 h·(10 a)-1),and most areas showed a downward trend.Wind speed decreased significantly(-0.096 m·s-1·(10 a)-1),with the most significant drop in the northern Tibetan plateau.Relative humidity,actual vapor pressure,precipitation,humidity index,and potential evapotranspiration are not obvious.In the past 60 years,the dividing line between humid and semi-humid areas of the Tibetan plateau has been pushed continuously to the southeast,and the semi-arid area has been expanding continuously.Potential evapotranspiration is most sensitive to actual water vapor pressure,followed by wind speed,daily maximum and minimum temperature,and least sensitive to sunshine hours.The sensitivity of potential evapotranspiration to wind speed,actual water pressure,maximum and minimum temperature,and sunshine hours increased significantly.The contribution of sunshine hours to potential evapotranspiration is the highest,followed by wind speed,daily maximum temperature,actual vapor pressure and daily minimum temperatureThe results of this paper will help us to deepen our understanding of climate change on the Tibetan plateau,and to a certain extent identify the main climate factors that affect the potential evapotranspiration change on the Tibetan plateau,so as to provide adaptive countermeasures for climate change on the Tibetan plateau.