Displaying NUCAPS data with Matlab

October 1st, 2021 |
NOAA-20 NUCAPS Temperature values at 853 mb, 1817-1819 UTC on 01 October 2021 (Click to enlarge)

Alexa Ross, a scientist at CIMSS (and CIMSS Blog contributor) has created a Matlab program that reads in NUCAPS EDR data from any Direct Broadcast datastream (here, for example), or from NOAA CLASS, and creates color-coded plots at NUCAPS data levels (that is, at any one of the 100 pressure levels used in the Radiative Transfer Model that drives the retrieval). Output from the program for four separate granules between 1817 and 1819 UTC is shown above. Temperatures are notably warmer over land than over the Atlantic Ocean, a temperature distribution in agreement with GFS model output (GFS model imagery from the College of Dupage website).

This program does not (as yet) indicate whether or not the retrieved profile has converged to a solution. It is up to a user to apply some quality control to the data. The very warm pixel at 1817 UTC over the Atlantic Ocean, for example, looks suspect. Cloud imagery is an important tool for anticipating whether a retrieval will converge — click here to see an 1820 UTC GOES-16 True-Color imagery over the scene, taken from the CSPP Geosphere site.

Gridded NUCAPS (available from this NASA SPoRT website) can also be used to view the horizontal distribution of temperatures across the NUCAPS data swath. The toggle below shows the 850-mb Temperature field and also the Quality Control flags.

850-mb gridded NUCAPS temperatures and Quality Flags from the NOAA-20 overpass at ~1815 UTC on 1 October 2021 (Click to enlarge)

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