和田地区植被覆盖变化及气候因子驱动分析

基于MODIS NDVI(2000—2016年)数据集,结合气温、降水数据,利用最大值合成法、斜率分析法及相关分析等方法,分析和田地区近17年的植被覆盖时空变化特征及其与气候因子的相关性。结果表明:(1)近17年和田地区植被覆盖的月际变化表现为先增加再减少,年际变化表现为显著上升趋势,增速为0.452/10a;(2)近17年和田地区植被覆盖增加和减少的区域分别占总面积的4.48%和0.21%,绿洲及昆仑山北部部分区域变化剧烈,高海拔区域基本不变;(3)近17年温度和降水小幅增加,增速分别为0.144/10a和0.156/10a;月尺度上,植被覆盖与温度为正相关,植被生长滞后于温度两个月;与降水以负相关为主,滞后效应不明显。(4)NDVI对气候因子响应的空间分布中,NDVI与平均温度以负相关为主,与降水以正相关为主,与降水的相关性较温度的相关性高;昆仑山北部植被对降水变化更敏感,和墨洛绿洲、策勒-于田绿洲和和田地区西南部山区对温度变化更敏感。

Spatial-temporal changes in vegetation characteristics and climate in Hotan Prefecture

To explore the relationship between vegetation cover change and climatic changes, we used MODIS NDVI (2000-2016) data set and climate (temperature and precipitation) data to analyze temporal and spatial variation characteristics of vegetation cover and its correlation with climatic factors in the Hotan Prefecture from 2000 to 2016. The results showed the following:(1) The data for inter-monthly changes in vegetation cover in the Hotan Prefecture during the last 17 years showed that vegetation cover first increased and then decreased. The inter-annual variation showed a significant upward trend, with a growth rate of 0.452/10a; (2) In the past 17 years, the areas where vegetation cover increased and decreased accounted for 4.48% and 0.21% of the total area, respectively. The oasis and the northern part of the Kunlun Mountains changed considerably, and the high-altitude area remained basically unchanged; (3) Over the past 17 years, temperature and precipitation increased slightly, with growth rates of 0.144/10a and 0.156/10a, respectively. On a monthly scale, vegetation cover was positively correlated with temperature, and vegetation growth lagged behind temperature for two months. There was a negative correlation with precipitation, but the lag effect was not obvious. (4) In the spatial distribution of NDVI response to climate factors, NDVI was negatively correlated with average temperature and positively correlated with precipitation. The correlation with precipitation was higher than that with temperature. Therefore, we conclude that vegetation in the northern Kunlun Mountains is more sensitive to precipitation changes, and the oasis and mountains in southwestern Hotan Prefecture are more sensitive to temperature changes.