Analytical Land–Atmosphere Radiometer Model

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Abstract
Conversion of radiometric land surface temperature (θr) to an equivalent isothermal (aerodynamic) surface temperature (θi) is important in balancing the land surface energy budget with satellite-based θr measurements. An analytical land–atmosphere radiometer model (ALARM) has been developed to convert θr taken at any zenith view angle to θi at a specified scalar roughness length z0h,i. Field data from 1987 and 1989 at the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) were used to evaluate the performance of ALARM. It was possible to find an optimal foliage temperature profile such that ALARM is consistent with these radiometric and atmospheric field data. The errors were significantly less when radiometer zenith angles were less than 40°. The foliage temperature at the canopy top θfh and the foliage temperature profile curvature parameter b were parameterized as functions of air temperature and leaf area index, respectively. Using these parameteri... Abstract Conversion of radiometric land surface temperature (θr) to an equivalent isothermal (aerodynamic) surface temperature (θi) is important in balancing the land surface energy budget with satellite-based θr measurements. An analytical land–atmosphere radiometer model (ALARM) has been developed to convert θr taken at any zenith view angle to θi at a specified scalar roughness length z0h,i. Field data from 1987 and 1989 at the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) were used to evaluate the performance of ALARM. It was possible to find an optimal foliage temperature profile such that ALARM is consistent with these radiometric and atmospheric field data. The errors were significantly less when radiometer zenith angles were less than 40°. The foliage temperature at the canopy top θfh and the foliage temperature profile curvature parameter b were parameterized as functions of air temperature and leaf area index, respectively. Using these parameteri...