Limb Correction of Infrared Imagery in Cloudy Regions for the Improved Interpretation of RGB Composites

Red-Green-Blue (RGB) composites combine information from several spectral channels into one composite image to aid in the operational analysis of atmospheric processes. However, individual spectral channels may be adversely affected by the limb effect, a result of an increasing optical path length of the absorbing atmosphere between the satellite and the earth as scan angle increases. Recent work has shown that limb effects can be accurately corrected in the individual imagery in clear regions using limb correction coefficients which vary with respect to latitude and season. However, in cloudy regions, the limb correction is inaccurate, which is problematic for forecasters when interpreting RGB composites designed to provide information about cloud properties and microphysics. This presentation will highlight an improved limb correction approach in the presence of clouds. Case examples demonstrating the improved correction in cloudy regions for several RGBs will be presented.