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Using ERA5 IBC with WRF in High resolution causes SST problem

sinan0310

New member
Hi,

I am fourth grade meteorology student in Istanbul Technical University and I am running a high resolution (4km) WRF simulation with (sst_update=1) ERA5 IBC over Black Sea basin for three month period and the problem that i am facing with is the SST and LANDSEA fields are not matching with each other. Thus it causes crazy air temperature over coasts when i use default METGRID.TBL (attached as 2mtemp.jpeg and sst.jpeg)

I've edited the METGRID.TBL with various options for SST field and you can see the results i've attached. I'd like to point that opt2.jpeg settings are interpolating the SST (I guess) to rivers (Dnieper) that flowing to Black Sea from Russia and Ukraine, as a result this affects the air temperature etc. around rivers. Next, I've tried op1.jpeg settings and the SST fields are acceptable for me but i wonder is there any better solution for this case? Thanks in advance

opt1.jpeg options

name=SST
interp_option=sixteen_pt+four_pt+wt_average_4pt
fill_missing=0.
missing_value=-1.E30
flag_in_output=FLAG_SST
interp_land_mask = LANDSEA(1)
masked=land

opt2.jpeg options

name=SST
interp_option=sixteen_pt+four_pt+wt_average_4pt+wt_average_16pt+search
fill_missing=0.
missing_value=-1.E30
flag_in_output=FLAG_SST
interp_land_mask = LANDSEA(1)
masked=land
 

Attachments

  • sst.jpeg
    sst.jpeg
    315.4 KB · Views: 22
  • opt2.jpeg
    opt2.jpeg
    188.1 KB · Views: 23
  • opt1.jpeg
    opt1.jpeg
    176.7 KB · Views: 26
  • landsea.jpeg
    landsea.jpeg
    152.8 KB · Views: 27
  • 2mtemp.jpeg
    2mtemp.jpeg
    788.6 KB · Views: 27
Hi,
Are you including the "invariant" file when you process the ERA5 data? Take a look at this FAQ to make sure you're doing it correctly.
 
I've tried the run with ERA5_INVARIANT and it said "ERROR: Cannot combine time-independent data with time-dependent data for field LANDSEA.mask"

I am running the simulation with modified METGRID.TBL (only SST field) only with interp_option=wt_average_16pt. For now, the results seems plausible
 
Have you tried running "avg_tsfc.exe" just before you run "metgrid.exe". This will use the air temperature from the rivers and lakes' surrounding gridpoints to produce a river temperature. It gives a more realistic lake and river temperature
 
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