2001-2021年西宁市植被覆盖时空变化特征分析

Temporal and Spatial Variation Characteristics of Vegetation Coverage in Xining City During 2001-2021

为揭示西宁市近20年植被覆盖的时空变化规律,为西宁市植被应对气候变化及生态良性发展提供科学指导,选取西宁市2001-2021年植被遥感数据,采用像元二分模型、最大值合成法及Slope趋势分析法等对西宁市植被覆盖变化特征进行分析,探究了研究期内西宁市植被覆盖的时空变化规律。结果表明:(1)在时间变化上,月际植被覆盖度呈现显著上升趋势,月总平均植被覆盖度在0.3412,由0.2963增长到了0.4222,其中7月份植被覆盖度(0.4222)最高,12月份(0.2963)最低。年均植被覆盖度呈现显著上升的趋势,由0.3350增长到0.3532。(2)在空间分布上,西宁市植被覆盖度呈现由西向东、由北向南增加的趋势。低植被覆盖区域呈现减少趋势,其余植被覆盖等级均呈现增加趋势。(3)在变化趋势上,2001-2021年植被覆盖度显著增加区域面积达到了33645.6 km^(2),占比为30.75%,植被覆盖度显著减少面积为30740.4 km^(2),占比为28.10%。2001-2021年植被覆盖度总体呈现上升趋势,未来西宁市生态环境建设的重点应该放在低植被覆盖区域。

In order to study the temporal and spatial changes of vegetation coverage in Xining city,vegetation remote sensing data from 2001 to 2021 were selected.The characteristics of vegetation coverage change in Xining city were analyzed by pixel dichotomy model and maximum synthesis method,and the temporal and spatial changes of vegetation coverage in Xining city were further revealed by slope trend analysis.The results showed that:(1) The monthly vegetation coverage showed a significant upward trend,and the monthly average vegetation coverage was around 0.3412,which increased from 0.2963 to 0.4222,with the highest vegetation coverage in July(0.4222) and the lowest in December(0.2963).The annual average vegetation coverage showed a significant upward trend,from 0.3350 to 0.3532.(2) In terms of spatial distribution,the vegetation coverage in Xining city showed an increasing trend from west to east and from north to south.The low vegetation coverage area shows a decreasing trend,while the other vegetation coverage levels all show an increasing trend.(3) In the change trend,from 2001 to 2021,the area where vegetation coverage increased significantly reached 33645.6 km^(2),accounting for 30.75%,and the area where vegetation coverage decreased significantly was 30740.4 km^(2),accounting for 28.10%.From 2001 to 2021,the vegetation coverage showed an overall upward trend,and the focus of ecological environment construction in Xining in the future should be on low vegetation coverage areas.