GOES-17 Level 2 Products are flowing over the SBN

September 30th, 2021 |
GOES-17 Shortwave Infrared imagery (3.9 µm), GOES-17 Fire Power and GOES-16 Fire Power, 1406 UTC, 30 September 2021 (Click to enlarge)

As of 1400 UTC on 30 September, GOES-17 Level 2 products are flowing into National Weather Service forecast offices via the Satellite Broadcast Network (SBN). An example of the improvement of GOES-17 v. GOES-16 is shown in the toggle above that samples the KNP Complex fire in Tulare County California (click here for a toggle that is not so zoomed in!). The GOES-17 shortwave IR shows warm pixels associated with the fire; GOES-17 Fire Power aligns with the GOES-17 pixels, and show much larger values (approximately 3x greater) than the GOES-16 products from the same time.

A further utility of Level 2 products is shown below, from 29 September. The Day Cloud Phase Distinction RGB includes ABI Band 5, the 1.61 ‘snow-ice’ band that indicates glaciation by a change in reflectance at that band. Thus, the color of the RGB can change where ice crystals are present. There is a Level 2 product, however, that computes what the phase most likely is, and that is shown in a toggle at 1951 UTC below. Visual inspection of an RGB may not be enough to ascertain cloud type, particularly on this day for the clouds off the coast of Oregon. A good practice is to load the Level 2 product underneath the image so that sampling can give a quantitative estimate, as shown at bottom.

Day Cloud Phase Distinction, 1731 – 1956 UTC on 29 September 2021 (Click to enlarge)
Toggle between the GOES-17 Day Cloud Phase Distinction RGB and the level 2 Cloud Phase product, 1951 UTC on 29 September 2021 (Click to enlarge)
GOES-17 Day Cloud Phase Distinction RGB with Cloud Phase beneath, sampled (Click to enlarge)

Available GOES-17 Level 2 Products include: Aerosol Detection and Aerosol Optical Depth, Rain Rate/Quantitative Precipitation Estimates (original algorithm), Clear Sky Mask, Fire Detection and Characterization (that is, Fire Hotspots), Land (and Sea) Surface Temperature, Derived Stability Indices, Total Precipitable Water, Derived Motion Wind Vectors, Cloud Particle Size Distribution, Cloud Top Pressure, Cloud Top Phase, Cloud Top Temperature and Cloud Optical Depth. The animation below (imagery courtesy Lee Byerle from TOWR-S) steps through the various Level 2 products at/around 1800 UTC on 30 September. Another version that loops through many GOES-17 Level 2 products. A visible band is included for reference.

GOES-17 Level 2 Products (and a 0.64 µm Band 2 visible image) at 1801 UTC on 30 September 2021 (Click to enlarge)

Special Note: Users of GOES-17 Level 2 Products must remember that, depending on the time and day, Level 2 Products may be affected by degraded ABI band quality, an issue related to the GOES-17 Loop Heat Pipe that is not performing up to spec. For more information on the Loop Heat Pipe and it effect on GOES-17 imagery, visit this site and this site.