Weather@home - procedure for creating ancillary files

Author: Mitchell Black ([email protected])

Note: The examples shown here are for generating the Dec 2013 -- Dec 2014 SST and SICE ancil files.

1. Sourcing OSTIA data

• MyOcean portal registration

• Download OSTIA SST (via MyOcean portal)

2. Regrid OSTIA SST and SICE to N96

bash regrid_OSTIA_N96.sh 2013 /data/ostia/2013

bash regrid_OSTIA_N96.sh 2014 /data/ostia/2014

Code: regrid_OSTIA_N96.sh

Operation: bash regrid_OSTIA_N96.sh {year_of_files_to_regrid} {path_to_directory_containing_files}

Required software modules: cdo, netcdf

Input: Directories containing daily OSTIA files downloaded from MyOcean portal.

Output: OSTIA_SICE_N96_2013.nc, OSTIA_SICE_N96_2014.nc, OSTIA_SST_N96_2013.nc, OSTIA_SST_N96_2014.nc

3. Calculate 5-day average OSTIA SST and SICE fields

SST:

bash calc_5daymean_OSTIA.sh ./OSTIA_SST_N96_2013.nc 2013 SST

bash calc_5daymean_OSTIA.sh ./OSTIA_SST_N96_2014.nc 2014 SST

SICE:

bash calc_5daymean_OSTIA.sh ./OSTIA_SICE_N96_2013.nc 2013 SICE

bash calc_5daymean_OSTIA.sh ./OSTIA_SICE_N96_2014.nc 2014 SICE

Code: calc_5daymean_OSTIA.sh

Operation: bash calc_5daymean_OSTIA.sh {infile} {year} {field: SST or SICE }

Required software modules: cdo

Input: OSTIA_SICE_N96_2013.nc, OSTIA_SICE_N96_2014.nc, OSTIA_SST_N96_2013.nc, OSTIA_SST_N96_2014.nc

Output: OSTIA_SICE_N96_2013_5daymean.nc, OSTIA_SICE_N96_2014_5daymean.nc, OSTIA_SST_N96_2013_5daymean.nc, OSTIA_SST_N96_2014_5daymean.nc

4. Select time steps for model year

SST:

cdo mergetime -selmon,12 OSTIA_SST_N96_2013_5daymean.nc -selmon,1,2,3,4,5,6,7,8,9,10,11,12 OSTIA_SST_N96_2014_5daymean.nc OSTIA_SST_N96_2013_12_2014_12.nc

SICE:

cdo mergetime -selmon,12 OSTIA_SICE_N96_2013_5daymean.nc -selmon,1,2,3,4,5,6,7,8,9,10,11,12 OSTIA_SICE_N96_2014_5daymean.nc OSTIA_SICE_N96_2013_12_2014_12.nc

Output: OSTIA_SST_N96_2013_12_2014_12.nc, OSTIA_SICE_N96_2013_12_2014_12.nc

5. Interpolate OSTIA fields over land

ncl ncl_interp_OSTIA_SST_overland.ncl

ncl ncl_interp_OSTIA_SICE_overland.ncl

Code: ncl_interp_OSTIA_SST_overland.ncl, ncl_interp_OSTIA_SICE_overland.ncl

Operation: change input and output name in scripts

Output: OSTIA_SICE_N96_2013_12_2014_12_interp_land.nc, OSTIA_SST_N96_2013_12_2014_12_interp_land.nc

6. Adapt land sea mask of HadAM3P model

HadAM3P land-sea mask: lsm_n96_add.nc

SST:

cdo -add lsm_n96_add.nc -invertlat OSTIA_SST_N96_2013_12_2014_12_interp_land.nc OSTIA_SST_N96_2013_12_2014_12_landmask.nc

SICE:

cdo -add lsm_n96_add.nc -invertlat OSTIA_SICE_N96_2013_12_2014_12_interp_land.nc OSTIA_SICE_N96_2013_12_2014_12_landmask.nc

7. Create ancillary files

• Clone Neil Massey's cpdn repository onto your machine.

python gen_cpdn_sst_sice_ancil.py OSTIA_SST_N96_2013_12_2014_12_landmask.nc tos OSTIA_SICE_N96_2013_12_2014_12_landmask.nc sic 2013

Code: gen_cpdn_sst_sice_ancil.py

Operation: gen_cpdn_sst_sice_ancil.py -h

Change path to Neil's cpdn repo (lines 18-19 of code)

Output: sice_ancil, sst_ancil

8. Check ancillary files

Unit	Check
no. time steps	78 (starting YYYY/12/03:12.00)
no. time steps	6 time steps per month
no. longitude	192 (0 to 358.125)
no. latitude	145 (90 to –90)
SST units	SURFACE TEMPERATURE AFTER TIMESTEP (K)
SICE units	SEA ICE FRACTION AFTER TIMESTEP (0—1)