天山山区草地变化与气候要素的时滞效应分析  

Temporal responses of NDVI to climate factors in TianShan Mountainous Area

作　　者：王桂钢[1,2] 周可法[1] 孙莉[1] 李雪梅[1,2] 秦艳芳[1,2] 

机构地区：[1]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院研究生院,北京100049

出　　处：《干旱区地理》2011年第2期317-324,共8页Arid Land Geography

基　　金：国家自然科学基金(40871204;40871028);国家自然科学青年基金项目(40601103)联合资助

摘　　要：通过选取新疆天山山区作为研究区,分析该地区气候参数(降水、温度、光照)对草地季节变化影响的滞后性特征。利用研究区内各气象站点的气温、降水和日照时数的逐旬数据、SPOTVGT时序数据和土地利用覆盖数据,运用时滞相关分析和GIS空间分析方法,根据13个滞后期(0-12旬)和13个时间尺度(1-13旬)分析了植被NDVI与同期及前期气温、降水、日照时数之间的相关关系。结果表明:天山山区草地长势与同期气温和降水的相关性较强,而与同期日照时数的相关关系较弱(0.099)。在1旬的时间尺度下,草地NDVI对气温、降水、日照时数响应的滞后时间分别为2旬、1旬和7旬。同时,考虑到草地的长势可能受到前期数旬气象条件的影响,进一步在多旬时间尺度下进行滞后分析。结果发现,就气温而言,草地与当旬气温和前2旬气温的累积量相关性最好;降水的滞后时间尺度略长于气温,当旬降水和之前一个月(0-3旬)降水累积量对于草地长势的影响最大;日照时数对于草地影响的最佳滞后时间尺度为10旬,草地NDVI与当旬和前9旬的日照时数累积量的相关性最好。Normalized Difference Vegetation Index(NDVI) is generally recognized as a good indicator of terrestrial vegetation productivity.Understanding climatic influences on NDVI enables prediction of productivity changes under different climatic scenarios.Temporal responses of remotely sensed NDVI to climate variables(air temperature,precipitation,sunshine hours) were examined in Tianshan Mountainous Area.Based on ten-day mean air temperature,precipitation and sunshine hours data,SPOT VGT NDVI data,and the LULC map,taking advantage of lag correlative analysis and GIS method,we calculated correlative coefficients between NDVI and air temperature,precipitation and sunshine hours,with climate variables in thirteen different time scale(1-13 ten-days) and thirteen different time lags(0-12 ten-days).The results show that correlative coefficients between remotely sensed NDVI and concurrent air temperature,precipitation are all significant in the Tianshan mountainous area,but correlative relationship between NDVI and concurrent sunshine hours was not statistically significant with correlative coefficient of 0.099.Response time of NDVI to air temperature,precipitation,sunshine hours separately is twenty days,ten days and seventy days.In the case of air temperature,NDVI is most strongly related to the sum of air temperature over about four ten-day periods.As far as precipitation is concerned,when the lag time reaches ten days period,correlative coefficient comes up to the most value.NDVI is most strongly related to the sum of precipitation over four ten-day periods.For sunshine hours,the correlative coefficient between NDVI and over ten ten-day periods(0-9 ten-day) accumulative sunshine hours is biggest in all combinations of time periods.

关 键 词：NDVI 气温 降水 日照时数 天山山区 

分 类 号：P461.7[天文地球—大气科学及气象学]