Premium
Estimation of surface heat flux and an index of soil moisture using adjoint‐state surface energy balance
Author(s) -
Castelli Fabio,
Entekhabi Dara,
Caporali Enrica
Publication year - 1999
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1999wr900140
Subject(s) - latent heat , energy balance , bowen ratio , heat flux , sensible heat , evaporation , environmental science , flux (metallurgy) , data assimilation , meteorology , heat transfer , mechanics , thermodynamics , materials science , physics , metallurgy
Estimates of surface heat flux and an index of the surface control over evaporation are made based on radiometric observations of ground temperature. A variational data assimilation approach is used to include surface energy balance in the estimation procedure as a physical constraint (the adjoint technique). This technique formulates the estimation problem as a minimization of ground temperature forecast misfits against observations. The surface energy balance equation is incorporated as a physical constraint. Applications to the First International Satellite Land Surface Climatology Project Field Experiment (FIFE) are presented. The procedure estimates of the surface control over latent heat flux match those values based on independent latent heat flux measurements. The estimates of surface heat flux, when compared with measurements, have a root‐mean‐square error of 20 W m −2 . The need to discriminate between soil wetness and aerodynamic contributions to the surface control over evaporation is recognized.