Comparing SPoRT ADAS To Other Operational Analyses

Brian Carcione at the Huntsville WFO did a brief write-up on some comparisons between the SPoRT ADAS hourly analysis and other operational analyses available to NWS forecasters in AWIPS and the observations themselves. What follows is a summary of his findings.

The following figures are difference fields between the SPoRT ADAS and the comparison analyses. Positive biases show the SPoRT ADAS is warmer than the comparison analysis; negative biases show the SPoRT ADAS is cooler than the comparison analysis. The results are for the 2100 UTC analysis on Monday, August 17, 2009.

The first image is a comparison between the SPoRT ADAS and LAPS temperature analyses. There are several bulls-eyes in the LAPS that did not match anything in the ADAS, and the ADAS showed cooler conditions all across the higher terrain. Both of these outcomes are expected as the LAPS analysis does not have the same quality control as the SPoRT ADAS product and has a tendency to not be able to resolve the highly-variable high-terrain temperatures.

SPoRT ADAS minus LAPS for temperature analysis at 2100 UTC on 8/17/09

The second image is a comparison between the SPoRT ADAS and Obs temperature analyses. Fewer large differences exist within the Huntsville area of responsibility, but there are a couple of notable exceptions. First is around Lake Guntersville where the Obs analysis first-guess field (the North American Mesoscale (NAM) model) is routinely too warm. The second is near the Cullman Airport in Vinemont, which is much cooler than the ADAS. This may be due to the Obs database ingesting exactly what the airport was reporting. Also of note is the large warm bias in the north Georgia mountains. This is not necessarily out of the ordinary because the NAM may again be warm biasing the Obs analysis.

SPoRT ADAS minus Obs for temperature analysis at 2100 UTC on 8/17/09

The third (and final) image is a comparison between the SPoRT ADAS and RTMA temperature analyses. These analyses are not significantly different, but there is increased warmth in the SPoRT ADAS over Northwest Georgia (similar to Obs) and many small-scale differences likely due to terrain resolution.

SPoRT ADAS minus RTMA for temperature analysis at 2100 UTC on 8/17/09

In each of these comparisons, the superior resolution and quality control of the SPoRT ADAS is apparent in producing an analysis with less bulls-eyes and more spatial variation over quickly changing terrain.

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