AIRS Rapid Response:
Latest Sulfur Dioxide and
Detection Time: 2021/04/13, UTC 18:05:21
Sulfur dioxide brightness temperature difference is calculated by differencing the values reported between two AIRS channels, one that is sensitive to SO2 and one that is not. Larger differences imply greater SO2 absorption, which in turn implies a stronger volcanic signal. Please refer to the opening paragraph on this page for a better understanding of what this measurement implies.
The cloud fraction reported by AIRS is the product of cloud emissivity and areal coverage. Low fraction can indicate either small, highly emissive clouds or more extensive but less emissive clouds. The cloud fraction shown here has a spatial resolution of 45 km at nadir. AIRS can sense up to two cloud decks in a column of atmosphere, and this plot shows the cloud fraction of all cloud decks present.
Cloud top altitude is calculated from the natural logarithm of the AIRS cloud top pressure assuming a surface pressure of 1000 hPa and a scale height of 6 km. The cloud altitude shown here has a spatial resolution of 45 km at nadir. AIRS can sense up to two cloud decks in a column of atmosphere, but in this plot only the higher of the two decks is depicted.
VISIBLE AND INFRARED
From the AIRS visible light sensor. Available daytime only.
AIRS' infrared sensor measures radiometric temperature (brightness temperature) at the top of the atmosphere over a wide spectral range, allowing determination of air temperature throughout the atmospheric column either above the clouds or at Earth's surface when not blocked by cloud. Useful for assessing cloud cover (clouds are colder than the underlying surface).