Update SWE in NOAH MP (Code related issue)

[Christina]

I am a PhD student trying to implement snowdrift in the WRF Model. For now the project looks really good apart from the fact that with Noah MP snow height is not being updated.

Maybe one can give me a hint to find the right place. I used the module_sf_noahmpdrv.F to modify SWE.

JLOOP : DO J=jts,jte
ILOOP : DO I = its, ite

......
SWE = MAX(0.0, SWE - 0.01) !FERO(I,J) * DT ) !+ grid%fdep(I,J) * DT)
SNOWERACC(I,J) = SNOWERACC(I,J) - 0.01 !FERO(I,J) *DT* (1/rhosn) *1000 ![m]
.....
ENDDO ILOOP ! of I loop
ENDDO JLOOP ! of J loop

!------------------------------------------------------
END SUBROUTINE noahmplsm

That was a test: to reduce SWE about 0.01 every time step.. but after one hour there was just a difference of 0.01 between the normal and the test run?? But SNOWERACC was much higher.

Is there somewhere in the code a line that overwrites SWE ?

I really tried my best to find it out by myself, but now I am running out of time for my PhD..

If anybody is familiar with the code.. please help me !

Christina

[Christina]

-----UPDATE------

Thanks to my wonderful colleague Emily Collier, we've found out that snow water equivalent (and therefore snow height) was not updated because of the snow layer ice variabel SNICEXY.

The modified snow water eq value is being overwritten in the module_sf_noahmplsm.F (subroutine COMBINE).

Therefore: to update snow water eq, I also updated snicexy.

Now it works

Christina