This minor release of MPAS corrects an issue with the initialization of the water vapor mixing ratio field in MPAS-Atmosphere, and it also adds two other fixes that should not affect model results.
The MPAS-Atmosphere initialization program (init_atmosphere_model) had previously assumed that any relative humidity field provided in an intermediate file was specified with respect to liquid water at or above 273.15 K, and with respect to ice below this temperature. However, intermediate files produced by the WPS's ungrib.exe program have the RH field adjusted so that is with respect to liquid water everywhere. With this release, the init_atmosphere core correctly interprets the RH field in producing the initial water vapor mixing ratio field. Note that, when initializing from a specific humidity (SPECHUMD) rather than RH, there is no change to results.
Besides the above fix, this release includes two other changes that should have no impact on results:
- The "units" and "description" for scalar tendencies have been corrected in the MPAS-Atmosphere Registry.xml file.
- The sign of the edgeNormalVectors field has been corrected for boundary edges that represent positive normal inflow. Although this change addresses a bug in the code, MPAS-Atmosphere does not have boundary edges, and other MPAS cores either employ no-flux or no-slip conditions along lateral boundaries or arrange such that all boundary edges represent positive outgoing normal velocity.
Thanks very much to The Weather Company for identifying the bug in initializing with relative humidity!