POLES  Sea Ice Model Forcing Data Set

Overview:

This data set provides atmospheric fields which can be used as forcing fields for driving dynamic/thermodynamic sea ice models of the
Arctic Ocean.
 

Variables:

 
Variable Variable name 
in programs 		 Unit  File name 
U-Component of the geostrophic wind u ms-1 poles_frc_wind.<yyyy><version>
V-Component of the geostrophic wind v ms-1 poles_frc_wind.<yyyy><version>
Surface Air Temperature temp K poles_frc_therm.<yyyy><version>
Specific Humidity  qa none poles_frc_therm.<yyyy><version> 
Downwelling Longwave radiation  flo Wm-2 poles_frc_therm.<yyyy><version>
Downwelling Shortwave radiation fsh Wm-2 poles_frc_therm.<yyyy><version>
1979-1993 mean ocean velocity at 40m depth uo, vo cms-1 poles_oflow
1979-1993 mean oceanic heat flux Wm-2 poles_oflux
 

Methods and data:

Geostrophic winds are calculated from the twice daily IABP sea-level pressures blended with the daily NCAR reanalysis
sea level pressures. The thermal forcing is calculated based on Parkinson and Washington(1979) using IABP-POLES surface air
temperature data provided by I. Rigor.

Ocean velocity and heat flux are output from a coupled ice-ocean model. The sea ice model is a multi-category thickness distribution model and the ocean model is a 3D primitive equation model (see Zhang et al. 1998).
 

Grid:

Grid Parameters for Poles Sea Ice Model Forcing Data Set.
Resolution: 160-km resolution Cartesian grid 
Projection:  Lambert-Equivalent (Equal Area)  Projection 
Grid Size:  Geostrophic wind and ocean velocity:  43x42 
Thermal forcing and oceanic heat flux  :   44x43 
Orientation: Positive x-axis lies on 35E meridian 
Negative y-axis lies on 55W meridian 
Origin:  The origin of the grid is at the north pole. Grid coordinates refer to the center of each grid cell. 
Conversion: Two Fortran programs which demonstrate the conversion of grid cell number to map projection coordinates x,y and latitude,longitude 
 coordinate conversion programs 
Spatial Coverage  The grid domain is shown here: <INSERT LINK> 
 
 

Temporal Coverage

Currently daily data  from 1/1/79 to 12/31/96 (Julian day 366 not included)
 

Data Format:

There are two sets of files. One set contains the geostrophic winds, the other the thermal forcing data.
The filenames are:
  • poles_frc_therm.<yyyy>.<version>
  • poles_frc_wind.<yyyy>.<version>

    • where yyyy is the year, and version refers to a version number. We occasionally updated these data sets so version numbers
    may change.

    The data are flat binary files (no headers)  consisting of short integers. The data were written as unformatted direct
    access files on an HP workstation using HP-UX 10.20. Byte order may have to be changed if you are using a machine
    using a different byte order (e.g. DEC, ooops Compac machines). A Fortran program demonstrating how to read the
    data is provided  The specific structure of the data set should be apparent from that program. Please let us know if  you have
    difficulty reading the data.

    Size:

    Wind forcing data set: 25 MB
    Thermal forcing data set: 45 MB
     

    Utilities:

    poles_frc_therm_grid.f : Fortran program to convert grid cell number to x,y, lat, lon for the thermal forcing grid
    poles_frc_wind_grid.f  :  Fortran program to convert grid cell number to x,y, lat, lon for the wind forcing grid.
    poles_frc_read.f :             Fortran program which demonstrates reading the data set.

    Data Access:

    You can access the data via FTP from here:  ftp://psc.apl.washington.edu/poles/ModelForcings

    If you are downloading the data, please send us an e-mail  to zhang@apl.washington.edu, so we can update you on changes, bugs etc.
     

    Attribution:

    The data set has most recently been used in the following papers:

    Zhang, J., D. A. Rothrock, and M. Steele, 1998: Warming of the Arctic Ocean by a strengthened Atlantic inflow: Model results,  Geophys. Res. Lett., 25, 1745-1748

    The figure captions are placed incorrectly in that paper.  For the correct placement, see

    Zhang, J., D.A. Rothrock, and M. Steele, 1998: Correction to "Warming of the Arctic Ocean by a strengthened Atlantic inflow: Model results", Geophys. Res. Lett., 25, 3541.
     

    If you are using the data and plan to publish the results, please use those references.

     

    Contact:

    If you have any questions or require additional information,  please contact Jinlun Zhang:  zhang@apl.washington.edu
     
     

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