黄土高原地区2001-2015年植被覆盖变化及气候影响因子

Vegetation Coverage Change and Climate Impact Factors in the Loess Plateau from 2001 to 2015

为研究国家"退耕还林还草"工程实施以来黄土高原植被覆盖动态变化,以2001-2015年的MODIS NDVI为数据源,结合2001-2015年的气象数据(温度/降水),分析黄土高原地区植被NDVI、气温和降水量的空间分布特征,以及植被NDVI对气温和降水量的响应关系。结果表明,近15a黄土高原地区植被NDVI总体呈现增长趋势。黄土高原地区植被NDVI的空间分布差异显著,大体趋势是植被覆盖从西北部向东南部逐渐递增。研究区植被的空间变化也具有明显的差异特征,研究区的西安市、渭南市及豫西山地的洛阳市等地的植被退化严重,但是随着国家"退耕还林还草"计划的实施,黄土高原地区中部的植被覆盖有了明显的改善。黄土高原地区的温度年际间变化不大,而降水量起伏变化较大。降水量对植被NDVI的影响大于温度对植被NDVI的影响。

The Loess Plateau is one of the most serious areas of soil erosion in China.In order to study the dynamic changes of vegetation coverage in the Loess Plateau since the implementation of the project of “returning farmland to forest and grass”,data of the MODIS (moderate resolution imaging spectrotadiometer) NDVI (normalized difference vegetation index) in 2001-2015 released by NASA,and local meteorological data were used to analyze the spatial distribution characteristics of NDVI,air temperature,and precipitation in the Loess Plateau,and to examine the response of vegetation NDVI to temperature and precipitation.The results showed that the vegetation NDVI in the Loess Plateau in recent 15 years showed an overall increasing trend.The spatial distribution of vegetation NDVI in the Loess Plateau was significantly different.The general trend was that the vegetation coverage gradually increased from northwest to southeast.The spatial variation of vegetation in the study area also had obviously different characteristics.The vegetation in Xi an,Weinan and Luoyang in the west of Henan Province degenerated seriously.However,with the implementation of the “returning farmland to forest and grassland” program,the vegetation coverage in the central part of the Loess Plateau had been significantly improved.The temperature in the Loess Plateau had little change over the years,but the fluctuation of precipitation changed a lot.The influence of precipitation on vegetation NDVI was greater than that of temperature on vegetation NDVI.