内蒙古草地生长季植被变化对气候因子的响应

基于MODIS NDVI数据,研究分析了2000-2010年内蒙古典型草原、草甸草原和荒漠草原生长季NDVI时空变化趋势,探讨不同类型草地生长季NDVI对温度、降水的响应。结果表明,内蒙古草地生长季NDVI整体年增长速率为0.735%,典型草原最为明显,年增长率达到1.063%;但是仍有31.807%的草地NDVI呈现下降趋势,其中典型草原、草甸草原和荒漠草原分别有8.664×10⁴、6.814×10⁴、2.841×10⁴ km²。除东北部草甸草原外,大部分草地生长季NDVI与降水量的相关性高于温度;草地生长季NDVI与温度和降水的相关系数均呈现出草甸草原>典型草原>荒漠草原的变化规律。内蒙古草地植被变化对温度和降水的响应具有滞后作用,且具有明显的经度地带性和纬度地带性特征,其滞后时间随着经度和纬度的增加逐渐减少。

Responses of Growing Season Vegetation Changes to Climatic Factors in Inner Mongolia Grassland

Based on the MODIS NDVI data, growing season NDVI spatiotemporal change was analyzed and relationships between NDVI and temperature, precipitation were also explored for typical steppe, meadow steppe and desert steppe in Inner Mongolia during 2000-2010. The results indicated that growing season NDVI was increased by 0.735% a^-1 in Inner Mongolia grassland. Typical steppe has significantly increased from 2000 to 2010 (1.063% a^-1). However, NDVI showed decreased trend in part areas, which accounted for 31.807% of the study area. Decreasing areas are 8.664×10⁴, 6.814×10⁴, 2.841×10⁴ km² for typical steppe, meadow steppe and desert steppe, respectively. Most of the grasslands excluding meadow steppe had a higher correlation with precipitation than temperature. Correlations between NDVI and temperature and precipitation had the similar trend: meadow steppe>typical steppe>desert steppe. In addition, the result also shows that responses of the grassland to temperature and precipitation changes have a conspicuous lag effect and the lag times have obvious longitude and latitude characteristics with increasing longitude and latitude.