Global Sea Ice (GIOMAS) Data Sets

GIOMAS (Globle Ice-Ocean Modeling and Assimilation System) Data:

The GIOMAS Data and some supporting programs can be grabbed here. The global sea ice thickness fields are illustrated by movies.

Variables:

VariableVariable nameDimensionUnitFile name
Sea ice thicknessheff2-Dmheff.H<yyyy>
Sea ice concentrationarea2-Dfractionarea.H<yyyy>
Sea ice velocity u and vicevel2-Dm/sicevel.H<yyyy>
Sea ice growth rate *iceprod2-Dm/siceprod.H<yyyy>
Sea ice melt tendency due to ocean heat flux **oflux_ocn2-Dm/soflux_ocn.H<yyyy>
Snow depth (water equivalent) ***snow2-Dmsnow.H<yyyy>
Ocean surface temperature (at 2.5 m)otemp12-DCotemp1.H<yyyy>
Ocean surface salinity (at 2.5 m)osali12-Dpsuosali1.H<yyyy>
Ocean surface velocity u and v (at 2.5 m)ouv12-Dcm/souv1.H<yyyy>

* Ice growth rate is the net ice production due to atmospheric heating/cooling and oceanic heat flux.
** When converted to W/m*m by multiplying a negative value of (-3.02*10**8), this variable becomes ocean heat flux to the mixed layer and can be used to drive global sea ice models.
*** To convert to actual snow depth, multiply a factor of (water density/snow density).

Methods and data:

SSM/I ice concentration data were assimilated in the TED sea ice model that is used in GIOMAS.

Grid:

Grid Parameters:

Grid configurationGeneralized curvilinear coordinate system
Grid Size:360 x 276
Spatial CoverageGlobal. The grid domain is shown here
lon and lat for scalar fieldsgrid.dat
lon and lat for vector fieldsgrid.dat.pop
angle between latitude line and  grid cell x-coordinate linealpha.fortran.dat

 

Temporal Coverage:

Currently monthly data  from 1/1979 to the present. Each file contains 12 monthly 2-D fields. For sea ice and ocean velocities, first comes 2-D u component followed by v component.

Data Format:

The data are flat binary files (no headers) consisting of single-precision floating-point numbers. The data were written as unformatted direct access files on a Linux PC cluster. Byte order may have to be changed if you are using a machine using a different byte order (e.g. HP workstations ). A FORTRAN program demonstrating how to read sea ice thickness and grid information is provided (read_hi_uice.f). An IDL program demonstrating how to read (and plot) scalar fields and grid information is also provided (read_draw_hi.pro). Another IDL routine (read_draw_uice.pro) is provided to read  vector fields and vector grid information. It also plots ice velocity on a spherical coordinate system using the angle between the latitude line and  the grid cell x-coordinate line (alpha.fortran.dat). The structure of the data sets should be apparent from these routines. Please let us know if  you have difficulty reading the data.

Utilities:

read_hi_uice.f  : FORTRAN program  to read sea ice thickness and grid information, can be used to read other scalar fields
read_draw_hi.pro : IDL program to read and plot sea ice thickness, can be used to read other scalar fields such as ice concentration and ice growth
read_draw_uice.pro : IDL program to read and plot sea ice velocity, can be used to read and plot other vector fields such as ocean velocity
colorbar.pro: IDL routine for drawing color bar
con_clr.pro:  IDL routine for setting colors
LLtoXY.pro: IDL routine for plotting vectors
LLtoXY_s.pro: IDL routine for plotting vectors
XYtoLL.pro:  IDL routine for plotting vectors
XYtoLL_s.pro:  IDL routine for plotting vectors
heads.pro:  IDL routine for plotting vectors
io.dat_360_276.output: model grid mask; ocean levels > 0, land = 0

Other Ways for Data Access:

You can access the data via sftp/ssh/rsync from pscfiles.apl.washington.edu/pcfiles/zhang/Global_seaice’, with the credentials:

username: ‘anonymous’
password: ‘anonymous’

If you are downloading the data, please e-mail us at zhang©apl•washington•edu  (zhang©apl•washington•edu)   we can update you on changes, bugs etc.

Other Related (Arctic Sea Ice-Ocean) Data Sets:

Attribution:

We’d appreciate your reference to the following paper for using the data:

Zhang, Jinlun and D.A. Rothrock: Modeling global sea ice with a thickness and enthalpy distribution model in generalized curvilinear coordinates, Mon. Wea. Rev. 131(5), 681-697, 2003.

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