Improve Documentation for Sigma Level Output

[gspetro-NOAA]

Background

A UPP user wanted to generate model output at user-defined sigma levels. UPP can output temperature, U, and V components on sigma surfaces (indices 206, 208, and 209 respectively in the GRIB2 table). However, there is no concrete documentation on how to format the XML files to allow this output. I provided the following information to the user:

• XMLs in the UPP/parm directory are a good starting place for configuring your own control XML file. In particular, the post_avblflds.xml file contains all of the fields that the UPP is currently able to output.
• Users can copy-paste the entries for temperature, U, and V (indices 206, 208, and 209) from that file into whichever XML file their workflow is currently using. The control file documentation explains more about the file.
• There is also some information on creating the flat text file from the XML, which includes validating the XML.

Additions Required

The user attempted to paste in the 206, 208, and 209 indices into her control file and created a flat file, but she experienced fortran I/O errors, even though her control XML did validate according to EMC_POST_CTRL_Schema.xsd. Documentation needs to be updated to:

• Add more documentation regarding what sigma levels are outputted by default. User pointed out that without looking at the source code, she would not have known that the only accepted sigma levels outputted by indices 206, 208, and 209 are the ones included between lines 342 and 363 of the SET_LVLSXML.f file.
• State that a <level></level> tag must also be included with the sigma levels to output
• Tell users to change the entries of ASIGO1 in SET_LVLSXML.f to their desired levels, recompile, and then making the sure tags explicitly outputted these levels.
• Note that just adding the level tags manually will allow UPP to compile and run successfully, but it will not produce any output.