应用遥感数据研究中国植被生态系统与气候的关系

Study on the Relationship Between Different Ecosystems and Climate in China Using NOAA/AVHRR data

应用 1 982～ 1 994年 NOAA/ AVHRR的归一化植被指数 (NDVI)资料和 587个气象台站的数据对我国不同类型植被生态系统和气候的关系进行研究。首先将我国的植被类型划分为2 1类 ,在此基础上分别研究了不同时间尺度下我国不同区域、不同植被类型和气候的关系。结果表明 :在多年平均状态下 ,植被生态系统 NDVI水平主要受水分条件的影响 ;年内变化上 ,温度对植被生态系统季相变化起着比降水略大的作用 ,年降水量造成了植被季相响应的差异。在年际变化上 ,分别研究了 4个季节和整个生长期尺度上的关系 ,一般情形为温度和降水对植被的年际波动起着大致相反的作用 ,不同植被类型在不同的生长时期 (季节 )对气候的变化响应方式也不同。发现在植被的生长期 ,我国南方和北方的植被生态系统对温度和降水的响应方式相反 ;同时存在 2个植被 -气候敏感区 。

Multiyear (12a) NOAA/AVHRR NDVI and meteorological station data were used to study the relationship between different ecosystems and climate in China In order to investigate the responses of different vegetation types to inter annual climate variability, we classified 21 vegetation types using GIS and the principal component analysis (PCA) Monthly NDVI was got for each meteorological station through its longitude and latitude The relations between averaged NDVI and precipitation, and temperature suggest that precipitation plays a more important part for the ecosystem than temperature does in China The relationship between NDVI and climate at an averaged year shows that temperature has a stronger force than precipitation, while precipitation causes different responses of vegetation to climate The correlations of seasonal variations between NDVI and precipitation, and temperature indicate that the responses of ecosystem to inter annual variability of climate differ at seasonal level, and that NDVI data in winter are inappropriate for investigating the variability of ecosystems in northern China To study ecosystem climate relationship at annual level, the data within growing period (April to October) for vegetation in most parts of China were used, and the results show that ecosystem climate relations for different regions differ greatly In southern China, there is a negative correlation between precipitation and NDVI and a positive correlation between temperature and NDVI; and vice versa in northern China Additionally, we found there are two sensitive (statistical significant) regions in responses of fluctuation of climate, and one is ecotone of grass forest in northern China and the other is central part of Yunnan province in Southwest China, respectively