Evaluate/ Validate Specific Humidity QC Procedures in Sonde YAML File and GSI

[PraveenKumar-NOAA]

A Sonde YAML file exists in GDASApp copied from UFO/ewok/jedi-gdas on June 28, 2022.

Before diving into replicating the PrepBUFR preprocessing for sonde specific humidity observations, we should first check that the QC procedures implemented in UFO match those being performed in GSI on PrepBUFR observations.

• Run GDASApp for the first week of August 2021 for Sonde observations
• Compare EffectiveQC against GsiEffectiveQC for specific humidity
• If there are differences, look at the related GSI source code
• Make any modifications to YAML as necessary

This issue will be used to track progress, including figures, statistics, and paths to files.

[PraveenKumar-NOAA]

Using a sonde YAML, without any QCs, I ran GDASApp for the specific_humidity and produced the following results.

Comparison of GSI and UFO H(x):

The differences between GSI and UFO H(x) are very small. The regression is on the 1:1 line, where the slope is 1 and the intercept is 0.0 for the observations that passed the QCs.

Number of observations passing/failing quality control

The totals counts, 16653, are the same between GsiEffectiveQC=0 and EffectiveQC=0. The totals are not the same between GsiEffectiveQC=1 and EffectiveQC!=0, 15291 and 61439, respectively. The number of counts of GsiEffectiveQC=1 is 15291 and for EffectiveQC!=0 is 61339. I don't know the reason for this discrepancy, need to talk about it.

Observation error assignment

Please look at the attached histogram plots. The differences between GsiFinalObsError and EffectiveError are small, but need to generate a plot for this.

[PraveenKumar-NOAA]

The number of observations that passed QCs is listed in the following document, https://docs.google.com/document/d/1_w6P-cJkxyYzTvLNMm6kCBWj2ZATk0PMsXOdKW29z8s/edit for three different YAML:

• YAML with no QC,
• YAML with QCs copied from an existing GDASapp sonde YAML, copied from UFO/ewok/jedi-gdas
• New (gsi) YAML