【摘要】 土壤湿度对植被指数起着重要的作用。利用NOAAAVHRR数据中的植被指数(NDVI)和我国气象台站所监测的土壤湿度数据,对我国北方地区的NDVI与土壤湿度的关系进行了研究。结果表明,近18年来,北方地区土壤湿度不同区域其变化趋势存在差异,西北地区土壤湿度在增加,而华北和东北地区土壤湿度在下降。NDVI对土壤湿度的响应也存在着明显的区域差异,我国西北地区植被对土壤湿度的敏感性最强,其次是华北地区,敏感性弱的是东北地区;对于不同层次的土壤湿度,也表现为同样的区域特点,但随着土壤深度的增加,敏感性减弱。这种敏感性也表现在不同季节变化上,春季华北地区土壤湿度对植被指数影响较大,其次是西北和东北地区,夏季和秋季北方地区土壤湿度与植被指数都有较好的相关性,以西北地区的相关系数最大,而冬季北方地区植被指数对土壤湿度都不敏感。更多还原

【Abstract】 Soil moisture had severe influence on vegetation index.Using normalized difference of vegetation index (NDVI) derived from 8km NOAA/AVHRR data,the soil moisture of surface layer of 0～10 cm and deeper layer of 10～20 cm from 1981 to 1998 was obtained from meteorological stations,and the vegetation index sensitivity to soil moisture in Northern China was studied.The result showed that the average soil moisture as a whole had a trend of decrease in Northeastern and Northern China,while a trend of increase in Northwestern China.The responses of vegetation index to soil moisture had evident differences in different sub-regions.The sensitivity of vegetation index to soil moisture was the strongest in Northwestern China,followed by Northern China and Northeastern China.This trend was also fit for deeper layer soil moisture,but only the extent was lower than that for surface layer soil moisture.The sensitivity was also reflected in various seasons.In spring,soil moisture had strong influence on vegetation index in Northern China (P<0.05),then Northwestern China and Northeastern China,orderly.In summer and autumn,the correlations were significant at the 0.05 level,while in winter the correlation between vegetation index and soil moisture was not obvious in all of the three regions.更多还原