Shortwave Albedo Product -

Basic: This GOES Imager product is an infrared channel difference similar to, but computed differently than, the original CIRA fire product. This product may better show fires in the morning and evening due to image enhancements. Hot spots appear white, as do low-level clouds. Fire/hot spots will come and go, usually covering only one or two pixels. More persistent and larger fires result in more continuous white spots. Clouds are generally distinguished from hot spots by their larger size and by their motion in an image loop. The colored portion of the image represents higher-level clouds (when present), to distinguish them from lower-level clouds and fires.

Advanced: The GOES shortwave albedo product is generated from the shortwave IR channel (3.9 µm) by subtracting the equivalent thermal radiance in the shortwave channel using the longwave IR (10.7 µm) temperature. This is done using the same formula day or night, whether or not there is reflected solar radiation. Since the surface albedo and emissivity are inversely related, areas that reflect solar radiation during the day are actually areas with lower emissivity or a radiance deficit, compared to the longwave IR channel, at night. The solar zenith angle at every image pixel is used to generate a normalized albedo, independent of sun angle. This new product, which emphasizes low-level water cloud features, also shows fire/hot spots both day and night. The colored portion of the image represents higher-level clouds (when present). For these higher clouds infrared temperatures are inserted and color-coded once the cloud top temperature drops below -30 deg Celsius.