基于MODIS-EVI的沱江流域植被覆盖度时空变化特征OA

Based on MODIS-EVI data acquired from the Google Earth Engine cloud platform,this study adopted Theil-Sen and Mann-Kendall(Sen-MK)trend analysis,coefficient of variation,Hurst index,distribution index and other methods to an-alyze the spatio-temporal variation characteristics of vegetation coverage in the Tuojiang River Basin from 2000 to 2024.The results showed that:(1)The vegetation coverage in the basin was dominated by moderate coverage,followed by high coverage,and low coverage accounting for the lowest proportion.Low coverage shows a relatively high proportion and obvi-ous distribution dominance in highly undulating mountains and extremely undulating mountains,while moderate and high coverage showed no significant distribution dominance.(2)In terms of the changing trend of vegetation coverage,the pro-portion of change types in descending order was unchanged,decreasing and increasing.The decreasing type was mainly distributed in plains and platforms,whereas the increasing type was concentrated in gently undulating mountains and mod-erately undulating mountains.(3)For the fluctuation characteristics of vegetation coverage changes,the proportion of fluc-tuation types from high to low was slight fluctuation,moderate fluctuation,severe fluctuation and stable state.Slight fluctu-ation was primarily distributed in platforms and hills,moderate fluctuation in gently undulating mountains,and severe fluc-tuation in moderately undulating mountains and highly undulating mountains.(4)The proportion of sustainability types of vegetation coverage changes in descending order was random change,future improvement,future degradation,continuous stability,continuous degradation and continuous improvement.The continuous degradation type was mainly distributed in plains and platforms,the future degradation type was concentrated in gently undulating mountains,and the continuous im-provement type was mostly found in moderately undulating mountains.