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-useand 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 imageryCollected by satellite that “scans” the earth rather than using a camera to photograph it. 4 spectral bands:visible RED, GREEN, and BLUEplus 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 Photography2000 IKONOS Imagery False natural color composite, bands 3-2-1 (RGB)1987 Digital Orthophoto True natural colorStep 1IKONOSInfrared false color composite, bands 4-2-1多波段图像合成Step 2Impervious cover layer generated using image classification processing techniques (PCA).Impervious cover in red, natural cover in black.However, forest canopy cover is still an issueIKONOS道路检测 Road detected!Canopy covering roadRoad detected under canopy shadowImpervious Cover LayerProcess 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 landG . Heat transfer to the ground (soil) H . Sensible heat flux loss to the air due to convection and conduction . Albedo . Emissivity(Radiance Balance)(Radiance Balance)(Heat Balance)(Heat Balance)Units : W/m2 Longwave (Lout)Shortwave (1- )SinLongwave (Lin)Longwave(1 - 0)Lin Radiation balanceNet radiation ( )Energy BalanceEnergy BalanceRn-G called available energy (or Qa)The latent energy flux of evaporation(w/m2): represented as E or ETor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Rnpath/row: 33/36ET (mm/d) estimation from Energy Balance Method June 16 2002June 16 2002ACHABAssimilation Code for HeAt and moisture Balance