基于GIS的祁连山植被NDVI对气温降水的旬响应分析

利用祁连山地区SPOTVGT-NDVI数据和气象站点旬平均气温、降水资料,运用最大化合成、趋势线分析和相关分析方法分析了祁连山植被的时空变化趋势,并从旬时间尺度上分析了祁连山植被对气温和降水的响应特征。结果表明:近10年来,祁连山年最大化植被NDVI增加了3.1%,植被改善、无变化和退化的面积分别占总面积的70.21%、21.44%和8.35%。祁连山植被NDVI对气温变化的响应大于降水,对气温和降水变化的最大响应滞后都为2旬左右。秋季植被NDVI对气温和降水变化响应最大,夏季植被NDVI对气温和降水响应的滞后期长于春季和秋季。祁连山植被NDVI对气温和降水变化的旬最大响应表现为中段大于东段和西段,NDVI对气温和降水变化的最大响应滞后期呈现出西段中段东段的空间分布特征。

Ten-day response of vegetation NDVI to the variations of temperature and pre-cipitation in Qilian Mountains based on GIS

This paper analyzed the spatio-temporal variations and the spatio-temporal responses of vegetation NDVI to the variations of temperature and precipitation in each ten-days period in the whole year, spring, summer and autumn covering 1998 to 2007 based on the SPOT VGT-NDVI data and ten-day temperature and precipitation data from 11 meteorological stations in Qilian Mountains. The results show that: the maximum values of annual NDVI has been increased with an rate of 3.1%/10a and the greening area, sta-ble area, and degraded area account for 70.21%, 21.44% and 8.35% of the total area respectively in Qilian Mountains. In Qilian Mountains, the response of vegetation NDVI to the variation of temperature is greater than to that of precipitation, vegetation NDVI maximally responds to the variation of temperature and precipitation with a lag of about 20 days. The response of vegetation NDVI to temperature and precipitation is the greatest in autumn, and the lag time is longer in summer. The maximum response of vegeta-tion NDVI to the variation of temperature and precipitation is greater in central parts than in the eastern and the western Qilian Mountains. There is more lag time of vegetation NDVI to the variation of temperature in the western and central parts, while less in the eastern parts.