Abstract:

To understand the spatial and temporal changes in functional areas of Qinghai, Normalized Difference Vegetation Index (NDVI) time series data from 2000 to 2015 were collected based on MOD13Q1 product. The coefficient of variation and trend analysis were combined to investigate the volatility and trend characteristic of vegetation. The results showed that vegetation NDVI was higher in southeast than that in northwest, and decreased from southeast to northwest and from east to west. NDVI frequency showed a M-type bimodal distribution in Three-river Source region, and the lowest unimodal distribution was appeared in Qaidam Basin. Lake area and east agriculture area showed similar unimodal distribution. As for CV, higher volatility distributed in lake area and east agriculture area, and lower volatility distributed in the edge of qaidam basin and the south of lake area. In terms of trend analysis, vegetation NDVI showed a fluctuating increase trend with 0.012·10a^-1 in Qinghai and a significant increase in Qaidam Basin and east agriculture area. This study revealed the effect of climate change and human activities on the trends of vegetation NDVI in functional areas, Qinghai, which provided a base data and scientific proof for ecology protection.

Key words: Normalized Differential Vegetation Index, Functional area, Trend analysis, Volatility analysis

摘要：

基于2000-2015年MOD13Q1的NDVI陆地专题的产品，揭示了青海省不同功能区植被时空分布特征及变化规律，应用趋势分析法阐述过去16年不同功能区NDVI的变化规律，及利用变异系数揭示NDVI稳定性分布规律。结果表明：青海省植被NDVI表现为东南偏高，西北偏低，由东南向西北、由东向西逐渐递减的分布特征。三江源地区NDVI频度分布呈"M"型的双峰模型，柴达木盆地为频度分布最低的单峰模型，东部农业区与环湖地区相似且频度略高的单峰模型。从CV分析，高稳定性地区分布在东部农业区和环湖地区，低稳定性地区分布在柴达木盆地边缘和青海湖南部。由趋势分析可知，过去16年青海省NDVI呈波动性缓慢上升趋势，变化率为0.012·10a^-1。东部农业区和柴达木盆地增加趋势显著。本文揭示了气候变化和人为因素双重作用下青海省不同功能区植被NDVI变化规律，为各区生态保护提供基础数据和科学参考。

关键词: 归一化植被指数, 功能区, 趋势分析, 稳定性分析