cloud mixing ratio isobaric surface wrong display

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Cloudy
Posts: 28
Joined: Tue Mar 02, 2010 12:15 am

cloud mixing ratio isobaric surface wrong display

Post by Cloudy »

When I load GFS 0.25 degrees from https://nomads.ncep.noaa.gov/cgi-bin/fi ... p25_1hr.pl, the variable "cloud mixing ratio isobaric surface" in Field Selector / Plan Views / Color-Filled Contour Plan View, to levels with 0 (zero) values fill the entire display with a single color. Same with Color-Shaded Plan View. When the variable is> 0 the display is normal. In Display Contour Plan View with values 0 the display is normal. Is this a bug?
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bobc
Posts: 987
Joined: Mon Nov 15, 2010 5:57 pm

Re: cloud mixing ratio isobaric surface wrong display

Post by bobc »

Hello,

I downloaded the 07/23/2021 0Z file (gfs.t00z.pgrb2.0p25.anl) from the URL you linked to. I loaded it through the General>Files/Directories chooser as a gridded data source, selected the "3D grid > Moisture > Cloud mixing ratio @ Isobaric surface", and the Color-Shaded Plan View display type. In the Level tab, I selected "70000 Pa" and clicked Create Display. This gave a display where many pixels had a value of 0 kg/kg, but many also had real values. For example:
Cloud Mixing Ratio at 700 hPa
Cloud Mixing Ratio at 700 hPa
Note that the Color-Filled Contour Plan View display is working for me as well at this level. By default, McIDAS-V will set the enhancement min/max values to match the data values. I lowered my max value to 5E-4 to get this display. If you are seeing all zero values, I'd suggest looking at the Level tab in the Field Selector to verify which level you are displaying. If you pick a level too high in the atmosphere (such as the default of 5000 Pa (50 hPa)) then all of the values will be zero as you reported.

Please let me know if you are still seeing all zero values after trying to display the data at multiple levels.

Thanks,
Bob Carp
McIDAS User Services

** Edited to change "0 g/kg to 0 kg/kg" in the first paragraph. Note that you can change the display's unit to g/kg by going to Edit>Change Display Unit in the Layer Controls. In the Change Unit window, enter a value of "g/kg" and click OK.
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