基于Google Earth Engine平台的大湄公河次区域2001—2019年植被NPP时空变化分析

Temporal and Spatial Analysis of Vegetation NPP in the Greater Mekong Subregion Based on Google Earth Engine Platform from 2001 to 2019

为探明大湄公河次区域植被净初级生产力(NPP)时空变化特征,基于Google Earth Engine(GEE)云计算平台,利用MOD17A3HGF NPP时序数据,采用线性趋势分析方法,分析了2001—2019年大湄公河次区域植被NPP的时空变化特征。结果显示:(1)2001—2019年间大湄公河次区域植被NPP总体较高,植被NPP年均值整体上变化趋势不显著,变化波动较大,且与年均温度有显著的负相关性;(2)大湄公河次区域植被NPP年均值具有较明显的空间分异性规律,大体呈中部高,南、西南部略低的状态,与其主要河流流域有着重要的联系;(3)植被NPP变化趋势呈现基本不变、轻微改善的特征,改善区域主要位于中国云南省与广西,轻微退化区域主要位于老挝中部和缅甸北部;(4)GEE云平台解决了本地平台数据下载与存储不便等问题,整个大湄公河次区域植被NPP时空变化的数据处理在10 min内完成,GEE云平台在大范围、长时间尺度的研究中体现出了强大的优势。

In order to understand the spatiotemporal characteristics of vegetation NPP in the Greater Mekong subregion,based on the Google Earth Engine cloud computing platform,using MOD17A3HGF NPP time series data,and using linear trend analysis methods,the spatiotemporal changes in vegetation NPP in the Greater Mekong subregion from 2001 to 2019 were analyzed.The results showed:(1)From 2001 to 2019,the vegetation NPP in the Greater Mekong Subregion was generally high,and the annual mean value of vegetation NPP showed no significant trend of change,with large fluctuation,and a significant negative correlation with the average annual temperature.(2)The annual average value of vegetation NPP in the Greater Mekong Subregion has obvious spatial divergence.It is generally high in the middle and slightly lower in the south and southwest,which is closely related to the main river basins.(3)The change trend of vegetation NPP is basically unchanged and slightly improved.The improvement areas are mainly located in China’s Yunnan and Guangxi provinces,and the slightly degraded areas are mainly located in central Laos and northern Myanmar.(4)The GEE cloud platform solves the problem of inconvenient data download and storage of the local platform.The data processing of temporal and spatial variation of vegetation NPP in the whole Greater Mekong subregion is completed within 10min.The GEE cloud platform shows strong advantages in large-scale and long-term research.