珠江流域植被NDVI对陆地水储量的响应分析

Response of vegetation NDVI to terrestrial water storage in the Pearl River Basin

本文基于GIMMS与重力恢复和气候实验(Gravity Recovery And Climate Experiment,GRACE)卫星遥感数据,利用相关分析和自回归模型等方法分析了2002―2015年珠江流域归一化差值植被指数(Normalized Difference Vegetation Index,NDVI)变化特征及其对陆地水储量的响应。研究表明,2002―2015年珠江流域NDVI年均值为0.67,总体上呈缓慢波动上升趋势,增速为0.21%/a,流域整体植被覆盖较好。珠江流域大部分地区的NDVI表现出缓慢上升趋势,植被覆盖度较高的地区主要分布在流域的北部和中部及海南岛等,较低区域主要分布在流域的西部和东南部等,植被绿度下降区域零星、碎片化分布于流域东北部及西部等区域。植被NDVI和陆地水储量距平值(Terrestrial Water Storage Anomaly,TWSA)的相关性整体较高,呈显著正相关的面积占比为88.12%,主要分布在珠江中部和西北部地区;海南岛和流域的东北部地区植被NDVI和TWSA相关性较弱。珠江流域43.2%的植被像素表现出较强的恢复力稳定性,而68.3%的植被像素对TWSA的抵抗力稳定性较强。植被对TWSA的抵抗力稳定性表现显著的较强区域主要分布在流域东部、中部和北部等地区,而珠江流域的西部、西北部和西南部等区域的植被则对TWSA变化较敏感。

This paper,based on GIMMS and GRACE satellite remote sensing data,uses correlation analysis and autoregressive model to analyze the change characteristics of NDVI and its response to land water storage in the Pearl River Basin from 2002 to 2015.The results showed that the average annual NDVI value is 0.67 in the Basin from 2002 to 2015,which generally showed a slow and fluctuating up trend,with a growth rate of 0.21%/a.The Basin as a whole has good vegetation coverage.NDVI in most areas of the Basin showed a slow up trend.The areas with greater vegetation coverage are mainly distributed in the northern and central parts of the Basin and Hainan Island,and the lower areas are mainly distributed in the western and southeastern parts of the Basin,the declining vegetation greenness areas are scattered in the northeast and west of the Basin.The correlation between vegetation NDVI and TWSA is generally high,and the positive correlation area accounts for 88.12%of the total area,mainly distributed in the central and northwestern parts of the Pearl River.While it is poor in Hainan Island and the northeastern part of the Basin.In the Basin,43.2%of vegetation pixels showed strong resilience stability,while 68.3%of vegetation pixels showed strong resistance stability to TWSA.The significant stability of vegetation resistance to TWSA were mainly distributed in the eastern,central and northern parts of the Pearl River Basin,while the vegetation in the western,northwest and southwestern parts of the Basin were more sensitive to TWSA changes.