近10年松嫩平原地表植被生长期的变化趋势

基于1998-2008年每15 d的SPOT NDVI数据集，对松嫩平原地表植被的生长状况进行建模分析，得到研究区域地表植被生长期的起始与终止日期以及生长期的持续天数。趋势分析结果表明,1）松嫩平原地表植被生长初期10年体变化稳定，局部地区有初始提前趋势，数值为10 d以上；2）研究区域内地表植被生长终期10年间有延后趋势，平均延后3 d左右；3）总体上，松嫩平原地表植被生长期稳定，有2~3 d的变化幅度。

Changes trend of terrestrial vegetation greenness period during recent 10 years in Songnen Plain

Based on GIS spatial analysis, the NDVI time series data of different vegetation types in northeast China were extracted by using the NDVI data from 1998 to 2008. Meanwhile, the phenological phases of vegetation types were simulated by Logistic function with their variation trends in 1998-2008. Results showed that 1) in 10 years, the date of vegetation beginning to grow was stable in Songnen Plain, and the growth trend in the local area was earlier than normal with a more than ten days value; 2) in the study area, the vegetation final date delayed evidently with a three day average scale; 3) in a word, the change trend of vegetation grown season in Songnen Plain fluctuates between 2 and 3 days.