北美永久湿地NDVI时序变化特征分析——以哈德逊湾西南湿地区域为例

Time Series Characteristics of NDVI in Permanent Wetlands in North America——A Case of Permanent Wetlands in the Southwest of Hudson Bay

基于2001~2009年MCD12Q1数据,提取哈德逊湾西南区连续9年都是湿地的区域作为研究区。利用1982~2006年GIMMS NDVI数据,分析此区域25a来NDVI季节、年际变化,并与温度、降水数据进行相关分析。结果显示:研究区域NDVI季节变化呈现单峰曲线形状,夏季达到最大值。1982~2006年NDVI年际变化在春秋两季与全年平均NDVI年际变化都呈增加趋势,夏季与冬季趋势则相反。此区域NDVI季节变化与温度、降水呈极显著相关,冬季NDVI年际变化与温度以及夏季NDVI年际变化与降水的相关性不显著,而其他各时期NDVI年际变化与温度、降水也都呈极显著相关。然而,由于人类活动及其他因素的影响,此区域的NDVI年际变化驱动还存在一定的不确定性。

In this study,MCD12Q1 over North America from 2001 to 2009 were downloaded,and their over-lapping area of the permanent wetlands was taken as the study area. GIMMS NDVI from 1982 to 2006 was used to explore the seasonal and inter-annual dynamics patterns, and their drivers used the Global Histori- cal Climatology Network-Monthly temperature and precipitation. The results showed that there was a single-peak curve for seasonal dynamics of NDVI, and the maximum value was appeared in the summer season. Generally, the average NDVI was increasing from 1982 to 2006 during spring, autumn, and the wholeof year,while NDVI was decreasing during summer and winter. A positive significant correlation （P^0.01） was observed between the seasonal variations of NDVI and temperature and precipitation around study area,as well as for annual variations of NDVI during spring,summer,autumn with temperature,and during spring, autumn, winter with precipitation showed positive correlation. However, due to the influence of human activities and other disturbances, some uncertainties still need to be studied in future.