鄱阳湖流域叶面积指数时空变化特征及其与气候因子的关系

利用1982~2001年NOAA/AVHRR NDVI数据，根据简单生物模型SiB2的方法计算鄱阳湖流域叶面积指数LAI，分析不同植被类型LAI年内和年际变化及其与降水、气温的关系。结果显示：在年内，LAI从1月开始减小，至3月降到最小，之后开始迅速增大，7月达到最大值，然后又开始减小；各植被覆盖类型LAI与前3月降水和前1月平均气温相关性较强，并且全部通过95％的显著性检验。在年际上，各植被覆盖类型LAI在20 a间无明显整体增大或减小趋势，但每隔2~3 a呈锯齿状增大减小交替变化，其中常绿针叶林LAI变幅较大，在23~35之间，而林地草原LAI变化较平缓，在05~09之间；植被LAI年际变化受流域内5~7月降水年际变化的影响较大。在空间上，植被LAI在春、冬季整体较小，空间分布差异也较小，仅在流域边缘山区林地覆盖区稍大，其余大片区域LAI值很低，且分布比较均一；夏、秋季LAI较大，空间分布差异也较大，其空间分布主要与流域内土地覆盖类型有关

SPATIAL AND TEMPORAL VARIABILITY OF LEAF AREA INDEX IN THE POYANG LAKE BASIN AND ITS RELATIONSHIP WITH CLIMATIC FACTORS

The simple biological model second version(SiB2 method) is used to calculate the leaf area index(LAI) of Poyang Lake basin,and analyze the annual and inter-annual relationship between LAI of different vegetation types and precipitation and air temperature based on NOAA/AVHRR NDVI data during 1982～2001.The results show that: in annual,LAI decreases from January to March to a minimum,then rapidly increases and reaches its maximum in July,and then begins to decrease again.The responses of LAI to precipitation and air temperature have a time lag of three month and one month respectively;in inter-annual,LAI of different vegetation types have no significant increase or decrease trend in 20 years,but every 2 to 3 years show an increase-decrease alternant variation.The inter-annual variation of LAI is mainly affected by the precipitation between May to July;in spatial,the distribution difference of LAI in spring and winter is small,only for forest covered area in the basin edge the LAI is slightly high and for the remaining large area the LAI value is very low and the distribution is relatively uniform.While in summer and autumn,the difference in the spatial distribution of LAI is large and mainly effected by the land cover types.