GEOS-ESM / GEOSgcm

GEOS Earth System Model GEOSgcm Fixture
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Update to RRTMGP v1.7, GEOSradiation_GridComp v1.8.0 #759

Closed mathomp4 closed 4 months ago

mathomp4 commented 4 months ago

This is a meta-PR for updating the components in GEOSgcm to use RRTMGP v1.7 which requires an updated GEOSradiation_GridComp as well:

To run RRTMGP v1.7 you also need a change in GEOSgcm_App currently in a PR: https://github.com/GEOS-ESM/GEOSgcm_App/pull/585

This is zero-diff for RRTMG runs, only changes RRTMGP runs.

Note also that RRTMGP v1.7 can be run in Single Precision mode with the CMake option:

-DRRTMGP_SINGLE_PRECISION=ON

Tests show that single-precision RRTMGP is about 10-20% faster than DP. But, for now we are keeping the default build to be double precision by default until further testing. Per @dr0cloud:

I have noticed around a -0.15W/m2 difference in global OSR in SP mode, but individual clouds can be -2 W/m2 or more.


Updates from GEOSradiation_GridComp v1.7

The above v1.8 tag also brings along updates from v1.7. As listed in #756, this also has effects.

The first is a small change needed for ongoing OceanBioGeoChem work (#28). To use this completely needs updates in GEOSgcm_GridComp and GOCART. Contact @mfmehari for more information.

The second is an update for on-going validation of RRTMGP (#33). This adds a new CMake option, ENABLE_SOLAR_RADVAL which is default OFF. Enabling it will enable many new exports for validation purposes.

This update is non-zero-diff for RRTMGP but that is not run by default currently. For RRTMG they are either zero-diff or 'truncation zero-diff', but these changes should only affect diagnostic outputs. That said, the Solar Internal Restart will have some changes (see below) but the overall state of the model is zero-diff with RRTMG: