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:
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 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.