阴山北麓地区近20年来植被生长状况及其年际变化研究

利用1981-2003年NOAA/AVHRR的归一化差值植被指数 (NDVI)数据,选用植被年总NDVI及其变异系数作为植被生长状况监测指标,分析两者的时间变化和空间分布特征,以此研究近20年来阴山北麓植被生长及其年际变化规律,在此基础上探讨自然和人为因素对两者的影响,得到如下结果:1)年降水量是影响研究区植被年总NDVI的主要因素,随着年降水量的增加,区域年总NDVI也有增大趋势,但年总NDVI分布不均衡,从南往北,年总NDVI呈阶梯状递减.2)研究区植被年总NDVI的变异系数为0.08,变异系数的空间分布与年总NDVI呈相似的阶梯状,不同的是由南向北呈逐渐递增趋势.人类活动影响了变异系数的大小,不同土地利用类型的变异系数从大到小依次为:草地,旱地,灌溉地.

STUDY ON VEGETATION GROWTH STATUS AND ITS INTERANNUAL CHANGE OF NORTH PIEDMONT OF YINSHAN MOUNTAIN IN RECENT 20 YEARS

Based on NOAA/AVHRR NDVI data from1981 to 2003,yearly total NDVI and its correlation of variance are calculated as two main monitoring indexes.Further,temporal and spatial characteristic of the yearly total NDVI and its correlation of variance are analyzed so as to help us understanding vegetation growth status and its inter-annual change of study area.Lastly,the potential driven factors of those temporal and spatial characteristic mentioned above are discussed.The conclusion is: 1) in general,yearly precipitation is the main factor that affects yearly total NDVI in the studied area.In recent 20 years,yearly total NDVI increases with increasing regional precipitation.But it decreases from south to north as ladder,being a disequilibrium pattern in space.2) The correlation of variance of whole regional is 0.08.It has a similar spatial pattern as yearly total NDVI has,but increases from south to north.Human activities influence the correlation of variance a lot,so that different landuse type has different correlation of variance.The correlation of variance of different landuse types can be ranked as follow: grassland,no-irrigated field,irrigated field.