Reasons behind seasonal and monthly precipitation variability in the Qinghai-Tibet Plateau and its surrounding areas during 1979∼2017

•SVI is used to characterize daily precipitation variability within a month/season/month in the QTP.•Precipitation variability decreased in the areas with low vegetation coverage.•Precipitation variability may increase in the southwest of the Himalayas foothills in the future.•Sea-land thermal difference between the Indian Ocean and the QTP is highly correlated with SVI.•Influence of East/South Asian monsoons on summer precipitation variability over QTP is complementary.