MPAS-A - RRTMG_SW / kissvec initialization issue

[briandobbins]

Hi all,

I'm not sure whether this should be classified as an MPAS-A bug or a CESM one, as I think the RRTMG code is pulled from there, but in the 'generate_stochastic_clouds_sw' routine inside 'src/core_atmosphere/physics/physics_wrf/module_ra_rrtmg_sw.F', at line 1701, there's the following test:

if (pmid(i,1).lt.pmid(i,2)) then
    stop 'MCICA_SUBCOL: KISSVEC SEED GENERATOR REQUIRES ... <cut>..'
endif

Following this, the bottom four levels of pmid [ pmid(i,1-4) ] are used to initialize the RNG stream, but there doesn't seem to be a need to check if pmid(i,1) > pmid(i,2), and this has caused a crash on a set of tests being run at KISTI using a 163K cell domain (60km, uniform). I've advised they simply comment out the test for the time being, but I'm not very familiar with this part of the code so I thought I'd pass this along as a bug for the experts to weigh in on.

Thanks,

• Brian