基于AVHRR NDVI的Shuttleworth-Wallace模型在韩江流域的应用

摘要

基于AVHRR NDVI(归一化植被指数)、IGBP土地覆盖及CRU气象数据,利用Shuttleworth-Wailace(s-W)模型估算韩江流域1981-2000年的潜在蒸散发(PET).结果表明,流域PET空间分布呈显著的非均匀性,从714.8～1 570.7 mm/a,主要受土地覆盖类型和地理位置影响；PET随植被类型和叶面积指数(LAI)季节性变化；输入数据的时空分辨率对PET的估算精度有较大影响；与Thomthwaite公式和FAO-56方法相比,S-W模型能够很好地反映地表变化对PET的影响.BTOPMC模型的应用表明,由S-W模型估算的PET在分布式水文模拟中取得了较好的效果.%Using AVHRR NDVI (normalized difference vegetation index) , IGBP land cover and CRU meteorological database, potential evapotranspiration (PET) over Hanjiang River basin in 1981 —2000 was estimated by Shuttleworth-Wallace ( S-W) model. Spatially, PET was distributed over the basin strikingly non-uniformly from 714. 8 mm to 1 570. 7 mm yearly, mainly because of the influence of land cover types and geographical location. Temporally, PET changed significantly with vegetation seasonal development, thus with vegetation leaf area index (LAI). Temporal and spatial resolutions of input data greatly affected PET estimation accuracy. Compared with Thomthwaite formula and FAO-56 method, S-W model can reflect the effects of vegetation change on PET very well. By applying the derived PET to a distributed hydrological model - BTOPMC, good results was achieved in the Hanjiang River basin.