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JCSDA-internal / ioda-converters

Various converters for getting obs data in and out of IODA
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[Bug] MRMS radar converter needs to distinguish between data void regions and below detectable limit signal #1474

Closed gthompsnJCSDA closed 4 months ago

gthompsnJCSDA commented 4 months ago

Current behavior (describe the bug)

Line 227 of mrms_grib2ioda.py is masking data outside the range of (-25, 80) dBZ so if there is a special value for data void regions separately from the points for which we know that the signal is present but below the detectable limit, then the distinction is lost during the format conversion. When this happens we eliminate the Location (lat,lon) variable where we still want to compute the HofX, so we need to keep these points from getting masked away.

To Reproduce

This happens behind the scenes so there is no special way to reproduce - you simply have to know what is done to the special values using the existing code.

Expected behavior

Provide the points of signal is present but below the detectable limit so the converter outputs those locations.

gthompsnJCSDA commented 4 months ago

A histogram of valid values and the special value of -99 was changed to -34.5 for showing easier in the histogram. Values in the data of -999 are locations where radar coverage is lacking.

dbz

gthompsnJCSDA commented 4 months ago

This graphic shows the importance of knowing where radar coverage exists but the signal is below detectable limits (no weather echo) versus the locations that are beyond radar range or blocked by terrain, etc.

mrms_ObsValue_3000m