DOI: 10.7289/v50z71kf
title: NOAA GOES-R Series Advanced Baseline Imager (ABI) Level 2 Derived Stability Indices (DSI)

description: The GOES-R Advanced Baseline Imager (ABI) Derived Stability Indices product contains images for five stability indices with pixel values that are indicators of atmospheric instability associated with convection and potential thunderstorm activity. 1) Convective(ly) Available Potential Energy (CAPE): A measure of atmospheric stability calculated by integrating the positive temperature difference between the surrounding atmosphere and a parcel of air lifted adiabatically from the surface to its equilibrium level. It exists under conditions of potential instability, and measures the potential energy per unit mass that would be released by the unstable parcel if it were able to convect upwards to equilibrium. Units of measure are joules per kilogram. 2) Lifted Index: The temperature difference between a parcel of air lifted adiabatically from the surface to a finishing air pressure of 500 hPa in the troposphere and the ambient air temperature at the finishing air pressure in the troposphere. The air parcel is "lifted" by moving the air parcel from the surface to the Lifting Condensation Level (dry adiabatically) and then from the Lifting Condensation Level to the finishing air pressure (wet adiabatically). Units of measure are kelvin. 3) K-Index: A measure of atmospheric stability indicating the potential of severe convection. The index is the difference in air temperature between 850 and 500 hPa, the dew point temperature at 850 hPa, and the difference between the air temperature and the dew point temperature at 700 hPa. Units of measure are kelvin. 4) Showalter Index: A measure of atmospheric stability indicating the convective and thunderstorm potential. The index is the temperature difference between a parcel of air lifted from 850 to 500 hPa (wet adiabatically) and the ambient air temperature at 500 hPa. Units of measure are kelvin. 5) Total Totals Index: A measure of atmospheric stability indicating the likelihood of severe convection. The index is derived from the difference in air temperature between 850 and 500 hPa (the vertical totals) and the difference between the dew point temperature at 850 hPa and the air temperature at 500 hPa (the cross totals). The index is the sum of the vertical and cross totals. Units of measure are kelvin. The product includes three types of data quality information. One describes the overall quality of the data pixels, providing an assessment of the derived stability indices data values for on-earth pixels. The second provides information about the quality of the physical retrieval for on-earth pixels, identifying failure conditions. The third provides information about the quality of the first guess skin temperature for onearth pixels, identifying temperature threshold failure conditions for on-earth pixels. The Derived Stability Indices product images are produced on the ABI fixed grid at 10 km resolution for Full Disk, CONUS, and Mesoscale coverage regions from GOES East and West. Product data is produced under the following conditions: Clear sky; Geolocated source data to local zenith angles of 80 degrees for both daytime and nighttime conditions.