CFSV2 landmask

Dataset specific topics involving WPS.

CFSV2 landmask

Postby nikhil003 » Tue Nov 01, 2016 3:44 am

I have been messing around with CFS v2 dataset and I have recently seen some problem with my data. I am not sure what is the way to correct it. I have downloaded the data without any subsetting, i.e. I am using the global files.

The two variable in metgrid file which I have compared, LANDMASK and LANDSEA, where I see that LANDSEA is shifted slightly to the right compared to LANDMASK. I have attached a plot of (delta_mask = LANDSEA-LANDMASK) and you can see that there is a clear shift between mask towards the right. I would appreciate if i can get some advice in sorting it out.

Image

For ungribbing, CFSv2 data, I am using the Vtable provided on rda.ucar.edu at below link

http://rda.ucar.edu/datasets/ds094.0/metadata/Vtable.RDA_ds094.0

I am not quite sure but i think the LANDSEA field is obtained from the data in CFSR grid files, while the LANDMASK are coming from GEOGRID, which creates this mismatch. I have tried the different suggestion given http://www2.mmm.ucar.edu/wrf/users/FAQ_files/FAQ_wps_input_data.html, but they didnt help me sort it out.

I have added the plots of sst with two different field, LANDMASK and LANDSEA, where the first picture if with LANDSEA, and it is quite obvious that the mask is not right.
Image

When, I put LANDMASK, it can be seen that the sst is masked with LANDMASK field, not using LANDSEA.
Image

while in the METGRID.TBL, i have specified to use LANDSEA.

Code: Select all
========================================
name=SST
        interp_option=sixteen_pt+four_pt
        fill_missing=0.
        missing_value=-1.E30
        masked=land
        interp_mask=landsea(1)
        flag_in_output=FLAG_SST
========================================


As you can see in zoomed in picture, the correct mask is not being used.
Image


I would be grateful if anyone can help me with this.
nikhil003
 
Posts: 6
Joined: Mon Nov 03, 2014 3:39 am

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