Antarctic and Arctic  Sea Ice Data
- From GIOMAS (Global Ice-Ocean Modeling and Assimilation System)

Polar Science Center



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GIOMAS Data:

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

Variables:


Variable
Variable name
Dimension
Unit
File name
Sea ice thickness
heff
2-D
m
heff.H<yyyy>
Sea ice concentration
area
2-D
fraction
area.H<yyyy>
Sea ice velocity u and v
icevel
2-D
m/s
icevel.H<yyyy>
Sea ice growth rate *
iceprod
2-D
m/s
iceprod.H<yyyy>
Sea ice melt tendency due to ocean heat flux **
oflux_ocn
2-D
m/s
oflux_ocn.H<yyyy>
Snow depth (water equivalent) ***
snow
2-D
m
snow.H<yyyy>
Ocean surface temperature (at 2.5 m)
otemp1
2-D
C
otemp1.H<yyyy>
Ocean surface salinity (at 2.5 m) osali1
2-D
psu
osali1.H<yyyy>
Ocean surface velocity u and v (at 2.5 m) ouv1
2-D
cm/s
ouv1.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 configuration
Generalized curvilinear coordinate system
Grid Size:  360 x 276
Spatial Coverage
Global. The grid domain is shown here
lon and lat for scalar fields
grid.dat
lon and lat for vector fields
grid.dat.pop
angle between latitude line and  grid cell x-coordinate line alpha.fortran.dat

Temporal Coverage:

Currently monthly data  from 1/1979 to 12/2009. 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 FTP by entering 'ftp psc.apl.washington.edu', then 'anonymous' as your log name, and your email address as password. After entering the web site, go to zhang/Global_seaice.
You can also access the data from here:  ftp://pscftp.apl.washington.edu/zhang/Global_seaice
If you are downloading the data, please e-mail us at 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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