泛祁连山地区植被动态变化及其对水热条件的响应

Vegetation dynamic changes and their responses to hydrothermal conditions in the Pan-Qilian Mountains

利用2005-2015年的MODIS产品中的MOD13Q1数据,提取泛祁连山地区的增强型植被指数(EVI),结合祁连山及周边地区37个气象站点的气温和降水数据,采用趋势分析、相关系数等方法,分析了泛祁连山地区植被动态变化及其对水热条件的响应.结果表明,泛祁连山地区植被整体覆盖度较低,EVI年均值为0.129;11 a来EVI年均值整体呈下降趋势,表明人为活动对泛祁连山地区的影响日渐加深.11 a间泛祁连山地区气温呈升高趋势,降水呈减少趋势,但总体上呈现明显的雨热同期现象,年均气温最高值与降水量最高值均出现在7月.植被对水热条件的响应具有时空一致性,相关性显著,相关性由强到弱依次为同期、提前半0.5月、提前1月、提前1.5月.

Based on MOD13Q1 of MODIS data from 2005 to 2015,the enhanced vegetation index(EVI)in the Pan-Qilian Mountains was extracted.The dynamic changes of vegetation and their responses to hydrothermal conditions in the Pan-Qilian Mountains were analyzed via trend analysis and correlation coefficient,combined with the temperature and precipitation data of 37 meteorological stations in the Qilian Mountains and its surrounding areas.The results showed that the overall vegetation coverage of the PanQilian Mountains was lower and the annual average value of EVI was 0.129.The annual average value of EVI showed a downward trend in the past 11 years,indicating that the influence of human activities on the Pan-Qilian Mountains was deepening day by day.Over the 11 years,the temperature there had shown a rising trend and the precipitation a decreasing trend,but in general,the phenomena of simultaneous rain and heat were more obvious,with the highest temperature occurring in the second half of July,which was consistent with the highest rainfall.The responses of vegetation to hydrothermal conditions were consistent in time and space,and the correlation was significant.The order of correlation was from being strong to weak first in the same period,then half month ahead,one month ahead and one and half month ahead.