Comparison of Atmospheric Clear-sky Shortwave Radiation Models to Collocated Satellite and Surface Measurements in Canada
Jing, X., and Cess, R.D., State University of New York at Stony Brook
Eighth Atmospheric Radiation Measurement (ARM) Science Team Meeting
Measurements of the top of the atmosphere (TOA) reflected shortwave radiation from the Earth Radiation Budget Satellite (ERBS) have been collocated with surface insolation measurements made at 24 Canadian stations located below 57 degrees latitude, which is the turning point of ERBS. These data are for 1985 through 1988 and additionally include collocated TIROS Operational Vertical Sounder (TOVS) water-vapor measurements. Advanced very high resolution radiometer (AVHRR) measurements of aerosol optical depth for three coastal stations are also available. Two atmospheric shortwave radiation models, one a model-derived TOA-to-surface transfer algorithm and the other a stand-alone column model, have been compared to the collocated datasets. Both models contain prescribed tropospheric aerosols that are uniform in space and time. The model-derived transfer algorithm and the column model are both in excellent agreement with the surface insolation measurements providing sufficient spatial averaging and temporal averaging. For daily means and individual stations, errors ranging from -6% to +10% are observed, and it is demonstrated that the cause is variability in aerosol loading; both models adopt constant aerosol loading. On average, however, the models' incorporation of aerosols seem quite realistic, at least for the region considered. There is no evidence that the models incorrectly portray any important physical processes.
