Temporal And Spatial Variation Of Snow Cover In China-Pakistan Economic Corridor From 2001 To 2019

Based on the data of snow products,Landsat OLI and ASMR?E passive microwave remote sensing data from 2001 to 2019,the paper analyzes the variation characteristics,interannual variation characteristics and spatial distribution characteristics of China Pakistan Economic Corridor in 2001?2019 by using remote sensing technology.In addition,the relationship between the spatial and temporal changes of snow cover and climate change is analyzed based on the meteorological data of ground stations.The results of this paper show that:(1)The snow cover area in the first year is generally established from mid-October,and the maximum snow cover area in January of the next year and the minimum snow cover in July.The snow area in winter is the largest and the smallest in summer.The snow area of China Pakistan Economic Corridor in 2001?2019 generally shows a decreasing trend.The snow cover distribution in the economic corridor of China and Pakistan is very uneven,and the northern area is obviously more than that in the south.The mountainous area and plateau area are high value areas with the snow cover frequency.The plain is the low value area of snow cover frequency,and the permanent snow cover is less,and the distribution of Hindu Kush and Himalayas is less,mainly concentrated in Karakoram mountains.In terms of the distribution range,it is mainly distributed in 4452?8378m.(2)The snow days in the economic corridor of China and Pakistan are increasing with the increase of altitude,and the spatial transformation of snow cover days in different sub zones is obvious.In the sub zone 1,sub zone 2 and sub zone 3,the main forms of snow cover are short-term snow areas,and the average distribution area in 19 years accounts for 88.182%,54.356% and 38.452% of the area of each sub zone.The main form of snow cover in the sub zone 4 is the middle and long-term snow area,and the average area of the study area accounts for 45.245% of the area.The main form of snow cover in sub zone 5 is long-term snow,and the average area of the snow in the study area accounts for 44.354% of the area of the study area.The number of snow cover days in 19 years has been declining,and fluctuates in some years.The spatial changes of short-term and mid-term snow areas are obvious,and the annual fluctuation is significant.(3)The average snow depth of China?Pakistan Economic Corridor fluctuates between4.28-8.01 cm in the study time,the maximum in 2008 is 8.01 cm,and the average snow depth in2014 is 4.28 cm,reaching the lowest value in 19 years.The average snow depth in the study area is 5.32 cm in 19 years.During the study period,the annual average snow depth of China?Pakistan Economic Corridor showed a downward trend,and the average snow depth in February reached the maximum.The snow depth is affected by topography,altitude,temperature,precipitation and other factors.The snow depth in the economic corridor of China Pakistan is different obviously in different sub zones,among which the average snow depth of sub zone 5 in 19 years is the highest 13 cm.