青海湖地区植被覆盖及其与气温降水变化的关系

Vegetation Coverage and Its Relation with Climate Change in Qinghai Lake Area

使用1981年到2003年月NDVI(归一化植被指数)资料,计算了青海湖地区植被覆盖度,分析了该地区植被覆盖度的历史演变,发现其值在增大,尤其是从1996到2003年,青海湖地区的植被覆盖度都为正距平,NDVI年平均增长率为1.07×10-3。四季的植被覆盖度均为增加趋势,夏季增加最多。月平均温度与月植被覆盖度、春夏季降水与夏秋季植被覆盖度显著正相关。因此,热量条件和春夏季降水是影响青海湖地区植被生长的关键性因素。

Based on the monthly AVHRR NDVI （Normalized Difference Vegetation Index） data during 1981-2003, the change of vegetation fraction in the Qinghai lake area and its relation with temperature and precipitation evolution were studied. It was found that the vegetation fraction anomaly generally showed an increasing trend, particularly, the anomaly was positive and the annual mean increment was about 1.07 × 10^3 from 1996 to 2003. In the recent 23 years, the seasonal vegetation fractions also showed increasing trend and the largest trend was in summer. Furthermore, the monthly mean temperature showed a marked positive correlation with the monthly vegetation fraction; spring and summer precipitation also showed a marked positive correlation with summer and autumn vegetation fraction. Therefore it is deduced that the quantity of heat and precipitation of spring and summer are key factors impacting vegetation growth.