Evaluating evapotranspiration rates and surface conditions using Landsat TM to estimate atmospheric resistance and surface resistance

摘要: A new method for a composite evaluation of atmospheric resistance, surface and evapotranspiration rate (λE) is applied to Landsat-5 TM. The uses three equations solve variables: the resistance between air (rae); (rs); vapour pressure at (es). novelty this approach estimation es, which assessed using decoupling coefficient (Ω) by Jarvis McNaughton [Adv. Ecol. Res. 15 (1986) 1]. input parameters are: temperature (Ts), net radiation (Rn), soil heat flux (G), (Ta), humidity (ea). time series (100 days) field data collected wheat crop used illustrate method, validated latent fluxes recorded eddy covariance technique. control rs on λE expressed through Surface Control Coefficient (SCC=1−Ω), compared moisture data. application technique in remote sensing monitoring context demonstrated Danish agricultural landscape containing crops different stages development. For satellite-based SCC, variables Ts, Rn, G are calculated basis TM, leaves solar irradiance (for computing Rn), Ta, ea as only required. directly applicable without any calibration when moist or vegetation cover dense. Only dry bare surface, where effective source area water below modification parameter (hs,max)