[Ncep.list.fv3-announce] NEMSfv3gfs and FV3 git repository updates 20190716

Jun Wang - NOAA Federal jun.wang at noaa.gov
Tue Jul 16 13:38:55 UTC 2019

Dear all,

Following changes were committed to the NEMSfv3gfs/FV3 repositories:

Ticket #65359 <https://vlab.ncep.noaa.gov/redmine/issues/65359>: fix some
issues when running FV3 with Noah MP
soil temperature over glacial ice was found to be too warm because the flag
value of 1 is used as the value of soil liquid water. There is no soil
hydraulic calculation over glacial ice in Noah LSM. Both soil total and
liquid are set to the flag value of 1. However Noah MP doesn't have soil
moisture evolution over this area. The use of 1 as soil liquid will cause
excessive heat release by freezing soil liquid water. To solve this issue,
we need to set the initial soil liquid to zero and set landice to false
when model is running with Noah MP. Another minor change is to set
undefined initial value to the Noah MP fields over ocean.

Ticket #65281 <https://vlab.ncep.noaa.gov/redmine/issues/65281>: Issue
about failure of hydrostatic run in FV3
It was found that the hydrostatic run of the latest FV3 failed in the
initialization process, while it has been successful using an earlier
version. It was confirmed after some tests that the FV3 commit hash#
f9ba7cee broke the hydrostatic run option. The missing code in f9ba7cee was
added back and the hydrostatic run works again.

Ticket #65794 <https://vlab.ncep.noaa.gov/redmine/issues/65794>: IAU
updates and adding enhanced divergence damping for EnKF DA
Following DA related code changes for GFSv16 implementation are added. 1)
the iau nfhour offset for the nemsio and log file output is used with IAU
run to generate history files consistent to current operational history
files. 2)some warnings that get printed on every task (just prints them on
the root task now) are removed. 3) an enhanced sponge layer if d2_bg_k2 = 0
(applies the enhanced divergence damping
given by d2_bg_k1 to the entire rayleigh damping layer, not just the top
two levels) is added. This will only change results if d2_bg_k2 is set to
zero in the namelist, which is not in all the current test runs. Items 1)
and 2) are needed for the IAU. Item 3) may be needed for the 127 layer
model as the large spread near the model top needs to be reduced in the
EnKF DA cycle.

Ticket #65359 <https://vlab.ncep.noaa.gov/redmine/issues/65359> changes
results for FV3 regression test fv3_gfdlmprad_noahmp. Results from other
regression tests do not change from this commit. Baseline results for
fv3_gfdlmprad_noahmp is updated. Regression test passed on theia and wcoss
phase1/2, cray and dell.


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