第10章5流域数据获取-土地利用覆盖-蒸散发数据.ppt

第十章 流域数据获取,5 土地利用-覆盖及蒸散发遥感数据获取 （流域空间数据和水循环数据）,内 容,1、土地利用-陆地覆盖研究的意义 2、 土地覆盖类别 3、遥感土地利用分类 4、蒸散发遥感数据获取,land-use and land-cover change,地表能量和水平衡 surface energy and water balance,albedo,roughness length,leaf-area index (lai),impervious,洪水 flood,1、土地利用-陆地覆盖研究的意义,不透水层,粗糙长度,叶面积指数,反照率,2、 不同的土地覆盖类别,land cover data 土地覆盖数据类别,1 城市和建设用地,2 农业用地,遥感土地利用-土地覆盖分类系统-四个尺度级别,陆地卫星,高高度航空遥感或卫星,中高度航空遥感或卫星,低高度,3 牧场,4 林地,5 水体,6 湿地,7 裸地,8 冻土,9 常年冰雪地带,ikonos high-resolution multispectral imagery collected by satellite that “scans” the earth rather than using a camera to photograph it. 4 spectral bands: visible red, green, and blue plus near infrared 4-meter ground pixel resolution.,3、遥感土地利用分类 不透水层识别,高分辨率多光谱卫星图像,satellite imagery vs. aerial photography,2000 ikonos imagery false natural color composite, bands 3-2-1 (rgb),1987 digital orthophoto true natural color,step 1,ikonos infrared false color composite, bands 4-2-1,多波段图像合成,step 2,impervious cover layer generated using image classification processing techniques (pca). impervious cover in red, natural cover in black. however, forest canopy cover is still an issue,ikonos,道路检测 road detected!,canopy covering road,road detected under canopy shadow,impervious cover layer,process for deriving impervious cover layer,图像掩模,4、蒸散发遥感数据获取,simplified hec-hms watershed runoff representation,水文建模应用的蒸散发,地表能量平衡,地表辐射平衡,地表辐射平衡,latent heat ( ),sensible heat (h),ground heat (g),. latent heat flux,. net radiation absorbed by the land,g . heat transfer to the ground (soil) h . sensible heat flux loss to the air due to convection and conduction,. albedo,. emissivity,(radiance balance),(heat balance),units : w/m2,longwave,(lout),shortwave (1- )sin,longwave,(lin),longwave,(1 - 0)lin,radiation balance,net radiation ( ),energy balance,energy balance,rn-g called available energy (or qa),the latent energy flux of evaporation(w/m2): represented as e or et,or,地表能量平衡,蒸散发估计,感热通量h,土壤热通量g,静辐射估计rn,path/row: 33/36,et (mm/d) est