Diurnal Variability of Regional Cloud and Clear-Sky Radiative Parameters Derived from GOES Data. Part I: Analysis Method

Abstract

A hybrid bispectral threshold method (HBTM) is developed for hourly regional cloud and radiative parameters from geostationary satellite visible and infrared radiance data. The quantities derived with the HBTM include equivalent blackbody temperatures for clear skies, for the total cloud cover and for the cloud cover at three levels in the atmosphere; the total fractional cloud cover and the fractional cloud amounts at three altitudes; and the clear-sky and total cloud reflectance characteristics. Geostationary satellite data taken during November 1978 are analyzed. A minimum reflectance technique is used to determine clear-sky brightness. A visible bidirectional reflectance model is derived for clear ocean areas. Clear-sky radiative temperature is found with a bispectral clear radiance technique during daylight hours. An empirical model is derived to predict clear-sky temperature at night. A combination of previously published infrared threshold and bispectral techniques is used to determine the... Abstract A hybrid bispectral threshold method (HBTM) is developed for hourly regional cloud and radiative parameters from geostationary satellite visible and infrared radiance data. The quantities derived with the HBTM include equivalent blackbody temperatures for clear skies, for the total cloud cover and for the cloud cover at three levels in the atmosphere; the total fractional cloud cover and the fractional cloud amounts at three altitudes; and the clear-sky and total cloud reflectance characteristics. Geostationary satellite data taken during November 1978 are analyzed. A minimum reflectance technique is used to determine clear-sky brightness. A visible bidirectional reflectance model is derived for clear ocean areas. Clear-sky radiative temperature is found with a bispectral clear radiance technique during daylight hours. An empirical model is derived to predict clear-sky temperature at night. A combination of previously published infrared threshold and bispectral techniques is used to determine the...