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(RESOLVED) SST update in WRF model, land values are zero in SST field

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mgolbazi

New member
Hi,

I am trying to use the NASA JPL SST data from “ https://podaac-tools.jpl.nasa.gov/drive/files/allData/ghrsst/data/L4/GLOB/JPL_OUROCEAN/G1SST”. I have successfully ran metgrid.exe and created the met_em_d0* files and have linked them in my WRF run directory. To set up my namelist.input for SST updates I have added the lines below:

&time_control
auxinput4_inname = "wrflowinp_d<domain>",
auxinput4_interval = 360,
io_form_auxinput4 = 2

&physics
sst_update = 1,
Rdlai2d = .true.,
usemonalb = .true.,

The model runs correctly and gives me a note of "SUCCESS COMPLETE WRF". However, when I check my wrfout_d0* files, in the SST field values assigned to the land are zero (which from my understanding is because “fill_missing” in METGRID.TBL was set to zero). Because of this, the albedo is also zero everywhere in wrfout file. In contrast, when I use default GFS data and do not update SST (default run), in the wrfout files the SST field has non-zero values over the land as well as over the ocean (same as the SKINTEMP variable in "met_em_d0*" files).

I checked the SKINTEMP field in my met_em_d0* files and they all look good and have assigned values for the land cells. However, the met_em_d0* files that are using NASA, SST data have a field called SST that the default runs do not.

I am stuck here and not sure how to resolve this problem. I have used the notes in the tutorial in “https://www2.mmm.ucar.edu/wrf/OnLineTutorial/CASES/SST/wrf.php”. But on this page, there is nothing mentioned about how SST should look after the runs.

I was wondering if you could advise me on this issue. Any help would be appreciated.

Thank you,
Maryam
 
Hi Maryam,
When you use the additional SST data and run metgrid, do you have normal SST values in your met_em* files, prior to running real and wrf?
 
Update:
I modified the METGRID.TBL prior to running metgrid as below:

========================================
name=SST
interp_option=four_pt
fill_missing=0.
masked=land
missing_value=-32768
flag_in_output=FLAG_SST
========================================

Could this be the reason? If so, how should I change it?
Not changing it created some weird interpolation/masking issues near the coastline and the SST values for the land cells were still zero.

In general, is it expected to have zero values over the land for the SST values in the output files? If so, why is it not zero for the default runs using GFS data? And if a non-zero value is expected for SST over the land, I wonder why is that? Because in my understanding the SST should represent the temperature over the sea surface and not the land.

Thank you!
 
Hi,
I'd like to apologize that I somehow overlooked the fact that, from the beginning, you have been saying that the values over land are zero. That is exactly what we would expect. As there is no sea surface, there is not sea surface temp over land. The GFS Vtable uses the variable SKINTEMP, which is providing the temperature values for the land.
 
Hi Maryam,

I am also trying to use G1SST data for WRF running.
Did you use netcdf-to-intermediate.f to do that? Did you add landsea (mask)
from G1SST data into SST file?
I can use netcdf-to-intermediate to generate SST, but I am not sure how to
add landsea from G1SST into SST file correctly?

I will be thankful if you have any suggestion about that.

Best

Lily
 
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