基于DEM分割小流域的水热效应评估--以福建省长汀县为例

摘要

A small watershed was used as evaluation unit based on DEM and remote sensing data to estimate the fractional vegetation coverage ( FVC) , land surface temperature ( LST) and wetness index ( WI) for Changting County. The results showed that:1 ) fractional vegetation cover changed signifi-cantly, with fractional vegetation coverage increased 15. 57% during 1988 and 2009 and its impact on thermal and moisture environment in the county where the soil erosion treatment was done well. In the last 21 years, Hetian basin increased mostly by 23. 48%, with an average annual increase rates about 1. 12%;2 ) FVC increase by 10%, which can reduce the mean LST 0. 54 ℃ ~ 1. 01 ℃, can in-crease the WI 109. 06 ~ 129. 22 , in the regression analysis;3 ) The temperature difference between inside and outside the Hetian basin declined from 2. 71 ℃ to 1. 09 ℃ during 1988 and 2009 , and the WI reduced from 589. 63 in 1988 to 334. 57 in 2009. The local eco-environment have been significantly improved within the last 21 years.%以DEM分割小流域作为评估单元,利用遥感数据提取长汀县的植被覆盖度( FVC)、陆地表面温度( LST)和湿度指数( WI)等作为评估因子,对长汀县水土流失治理的水热环境效应进行定量评估。研究表明：1)21年间,全县植被覆盖度增加明显,提高了15．57%,而河田盆地增幅最大,提高了23．48%,年均提高约1．12%；2)在回归分析中, FVC均值每增加10%,可降低LST均值0．54~1．01℃,可增加WI均值109．06~129．22；3)1988年—2009年,河田盆地内外温差由2．71℃降低到了1．09℃, WI差由589．63降低到了334．57,水土流失治理效果逐年改观。