利用内蒙古中部荒漠草原区2011—2015年的 INDV和降水等资料,分析了研究区 INDV时空变化特征及 INDV对降水和气温的响应特征.结果表明,研究区 INDV在2012年达到5年中的最高水平,2013—2015年则呈下降趋势.从空间范围来看,研究区由西向东、由北向南表现出 INDV逐渐增高的趋势.相对于气温因子,降水量对研究区 INDV变化起到关键作用,降水量南多北少是研究区 INDV南北差异的主要原因.南部地区利用地下水进行农田灌溉,加剧了 INDV的空间差异.植被返青时期(5月初)的降水对全年 INDV的提升至关重要,而7—9月降水量变化对 INDV的影响明显减弱.除个别雨量充沛的年份以外,研究区北部在每年7—8月反而出现了年内 INDV的较低值,这主要是由于冬季冰雪融水有助于植被返青,但春末及夏季少雨、高温的条件不利于植被发育甚至存活.研究区北部受人类影响较小的荒漠草原区 INDV对降水量波动的敏感性强于研究区南部.%The INDV spatial-temporal variation and its response to precipitation and air temperature are analyzed using the newest GIMMS INDV3g.v1 and meteorology data from 2011 to 2015 in the study area. The results show that the average INDVvalues reached its maximum in 2012 and then decreased gradually over the next three years.The spatial variation characteristic of INDVis in an increasing trend from north to south and from west to east in our study area.Compared to air temperature,the precipitation is the key factor that affected the INDVfluctuation.T he diminution of precipitation from south to north is the major reason leading to the INDVvariation,and the irrigation with pumping groundwater in the southern part has aggravated this variation.The precipitation in the period of grass regeneration(first half of May)can prominently affect the annual INDV,but this influence of precipitation from July to September become weaker.The relatively high INDVin regeneration period is mainly caused by the melt-water from winter and rainfall in spring.The low INDVvalues in July and August in northern part of study area result from the high temperature and low precipitation compared with that in the southern part.The sensitivity of INDVto precipitation is high in the north part of desert steppe,where human activities are relatively weak.
展开▼
