青藏高原积雪覆盖日数时空变化特征OA

Snow cover,as the main existing form of cryosphere on the Tibetan Plateau,is the seasonally fastest changing surface feature.The Tibetan Plateau constitutes the largest high mountain snow and ice-covered area in the Northern Hemisphere and the main snow-covered area in High Mountain Asia.Considering that the variation of snow cover in the high mountain regions of the Tibetan Plateau is largely unknown and research on snow cov-er days(SCDs)on the Tibetan Plateau is inadequate,we analyzed the spatiotemporal variations of the number of SCDs on the Tibetan Plateau from 2004 to 2021 based on the daily NOAA IMS 4 km snow and ice products.The results indicate the following.(1)Over the past 17 years,the number of SCDs on the Tibetan Plateau has in-creased markedly at the rate of 11.5 d·(10a)-1.Spatially,the number of SCDs in the high-altitude areas mainly in-creased in the central and eastern parts but decreased in the south and northwest.(2)The number of SCDs on the Tibetan Plateau exhibits a considerable dependence on elevation;the higher the elevation,the longer the snow cover duration and the greater the number of SCDs.The mean number of SCDs is less than 5 days below 2000 m a.s.l.,whereas it exceeds 157 d at 6000 m a.s.l.(3)The annual mean number of SCDs is 71.1 d,with the highest in winter(27.2 d),followed by spring(22.1 d),autumn(14.5 d),and summer(5.3 d).(4)In a general warming and wetting environment in the Tibetan Plateau,the increase in snow cover over the past decade due to more pre-cipitation in high-altitude and high-latitude areas has effectively compensated for the decrease in snow cover due to temperature increase.