中文摘要：

利用内蒙古科左后旗草甸草地2000--2006年MODIS的8d合成归一化植被指数（NDVI）资料和逐日气象资料，分析了研究区NDVI的季节变化和年际变化特点以及NDVI与气象因子的关系．结果表明：季节变化过程中，研究区水汽压与NDVI的相关程度明显大于降水量；积温和累积降水量共同控制着各年草地的返青速度，草地增长期（6、7月）的降水量对NDVI年最大值的影响比年总降水量更显著；时滞分析表明，水汽压对之后约12d的NDVI有持续的显著影响，平均气温的时滞为11～15d，降水量对NDVI影响的累积时滞双重效应可达36～52d．

英文摘要：

Based on the 2000-2006 MODIS 8-day composite NDVI and day-by-day meteorological data, the seasonal and inter-annual variations of Horqin meadow NDVI as well as the relationships between the NDVI and relevant meteorological factors were studied. The results showed that as for the seasonal variation, Horqin meadow NDVI was more related to water vapor pressure than to precipitation. Cumulated temperature and cumulated precipitation together affected the inter-annual turning-green period significantly, and the precipitation in growth season （June and July）, compared with that in whole year, had more obvious effects on the annual maximal NDVI. The analysis of time lag effect indicated that water vapor pressure had a persistent （about 12 days） prominent effect on the NDVI. The time lag effect of mean air temperature was 11-15 days, and the cumulated dual effect of the temperature and precipitation was 36-52 days.