Spatial and temporal distribution of vegetation coverage and its response to meteorological factors in frozen soil region of Qinghai-Xizang Plateau
In view of the problem that global warming has led to the continuous degradation of frozen soil on the Qinghai-Xizang Plateau,which in turn affects the growth of vegetation on frozen soil,the pixel dichotomy was used in this paper to invert its corresponding fractional vegetation coverage (FVC ) based on the MOD13Q1 normalized vegetation index from 2001 to 2020.Finally,the spatial and temporal distribution of FVC and its response mechanism to meteorological factors were studied by trend analysis and correlation analysis.The results showed that in the past 20 years,the mean value of FVC in the frozen soil region of the Qinghai-Xizang Plateau had shown an increasing trend as a whole,and the growth rate was patchy permafrost region(0.0017/a)>seasonal frozen soil region(0.0010/a)>permafrost region(0.0008/a)>island permafrost region(0.0005/a);the spatial distribution of FVC in the frozen soil area of the Qinghai-Xizang Plateau was characterized by"low in the northwest and high in the southeast".In terms of spatial variation trend,FVC in the frozen soil area of the Qinghai-Xizang Plateau was mainly stable,but it showed an improving trend;the proportion of significantly increased area was greater than that of significantly reduced area,which was patchy permafrost area(30.26％)>permafrost area(24.04％)>seasonal frozen soil area (12.06％)>island permafrost area (8.24％).FVC in the frozen soil region of the Qinghai-Xizang Plateau was affected by two meteorological factors,temperature and precipitation,but the correlation with precipitation was stronger.With the increase of temperature,the correlation between FVC and temperature in the frozen soil region of the Qinghai-Xizang Plateau changed from positive correlation to negative correlation.Therefore,in the long run,the frozen soil degradation caused by global warming is not conducive to vegetation growth.
FVCtime-space distributionclimateNDVIfrozen soil region on Qinghai-Xizang Plateau
万方数据
维普
