SST Data

Most data sets do not contain SST data. SST data are not required by the WRF model, but when running very long simulations, it is beneficial to have for updating SST during the model run. If you plan on running the model over long periods of time, a good source of SST data is the NCEP SST analysis.

Type: GRIB1 / GRIB2 data

Resolution:

0.5 deg global data (more recently a 1/12 degree data set has become available, but read their changes log before using this data)
Output frequency - daily

Availability:

The 0.5 degree data are available since 2001-02-11, while the 1/12 degree data are available since 2007-06-29

From NCEP's anonymous ftp site
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.YYYYMMDDHH (for the most resent data - GRIB1 and GRIB2)
ftp://polar.ncep.noaa.gov/pub/history/sst (historic 0.5 degree data - only GRIB1)
ftp://polar.ncep.noaa.gov/pub/history/sst/ophi (historic 1/12 degree data - only GRIB1)

Vtable: Vtable.SST

Peruse the ungrib/Variable_Tables/Vtable.SST file to see which fields we are going to unpack from the GRIB files.

 

Sample data (August 2005):

0.5 degree GRIB1 data, available for the period 2005-08-27_00 to 2005-09-01_00 (data frequency is daily).
This data corresponds to the Hurricane Katrina dates.

Notes on running UNGRIB for this data

1. Download data and place in directory ../DATA/SST
2. Examine the GRIB files, e.g.,
   ./util/g1print.exe ../DATA/SST/rtg_sst_grb_0.5.20050828
3. ln -sf ungrib/Variable_Tables/Vtable.SST Vtable
4. ./link_grib.csh ../DATA/SST/rtg_sst_grb_0.5
5 . Edit namelist.wps
    start_date = '2005-08-28_00:00:00',
    end_date = '2005-08-30_00:00:00',
    interval_seconds = 21600,
    prefix = 'SST',
6. ./ungrib.exe >& ungrib_data.log
7.Examine the intermediate files, e.g.,
   ./util/rd_intermediate.exe SST:2005-08-28_00
   ncl util/plotfmt.ncl 'filename="SST:2005-08-28_00"'

 

Notes on running METGRID for this data

When running metgrid, we can choose to:

(1) add SST for the initial time only (this is good enough for short runs, where SST is not updated during the WRF model run)

fg_name = 'FILE'
constants_name = './SST:2005-08-28_00'

(2) add SST fields at each time

fg_name = 'FILE', 'SST'