Spatial and Temporal Variations of Cloud Parameters over the Qinghai-Xizang Plateau during the Past Two Decades

Abstract

Accurate estimation of cloud cover is the basis for understanding the spatial and temporal characteristic of cloud parameters on the Qinghai-Xiznag Plateau （QXP）.The dynamic changes in cloud distribution on the Qinghai-Xiznag Plateau are analyzed by the correlation analysis， regression analysis and trend analysis method.Using the MODIS cloud daily product （MOD08_D3） data and ERA5 reanalysis data from 2000 to 2020， the temporal and spatial characteristics of cloud distribution and cloud parameters in different phases over the Tibetan Plateau are analyzed.The results show that the high cloud cover center is located in Medog County （77.3%）， and Nyingchi （72.5%） is the maximum cloud cloud-covered area.The total cloud cover over the QXP has decreased by 0.04% in the past 21 years.Regarding seasonal distribution， the probability of liquid water clouds present in Summer is the highest （31.7%）， and the probability of ice clouds present in Spring is the highest （26.5%）.The ice cloud occurrence per year is about 2% more than liquid cloud.Under the background of global warming， the atmospheric water vapor over the QXP shows a decreasing trend， whereas the cloud water content shows a gradually increasing trend.The annual average cloud water vapor is about 0.01 cm higher than the total atmospheric water vapor， and the total cloud water vapor increased by about 0.04 cm.This study provides a basis for understanding the influence of cloud water resources on global climate change and the water cycle over the QXP.

Keywords

• qinghai-xizang plateau （qxp）
• reanalysis data
• cloud distribution
• cloud parameters
• spatioal and temporal characteristics