Projections of an Ice-Diminished Arctic Ocean
- Retrospection and Future Projection

   Jinlun Zhang, D. Andrew Rothrock, and Michael Steele

  Polar Science Center, Applied Physics Laboratory, University of Washington
NSF logo

Funded by The National Science Foundation Arctic Program, Grant OPP0240916

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PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System) Data Sets from the Retrospective Investigation

Overview:

The PIOMAS Data Sets from the retrospective investigation include model output for 1978-2005. We provide the output from the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS) for best possible estimates of some key ice and ocean variables. The data sets only include results for the period of 1978-2005 when satellite ice concentration data are available for assimilation. These data sets include arctic sea ice thickness and concentration, snow depth, ice growth rate, ocean surface salinity, and more...

The sea ice thickness fields are illustrated by movies

Variables:

 
Variable Variable name 
in programs 
Dimension
Unit  File name 
Sea ice thickness, monthly mean
    heff
    2-D
  m heff.H<yyyy>
Sea ice thickness in text files
   heff.txt
    2-D
  m
heff.txt<yyyy>
Sea ice thickness, daily mean
    hiday
    2-D
  m
hiday.H<yyyy>
Sea ice concentration
    area
    2-D

area.H<yyyy>
Snow depth (water equivalent)
    snow
    2-D
  m
snow.H<yyyy>
Snow depth daily (water equivalent)    snowday


snowday.H<yyyy>
Sea ice growth or melt rate, (meter of ice)/s
    iceprod
    2-D
  m/s
iceprod.H<yyyy>
Sea ice velocity, u and v components
    icevel
    2-D
 m/s
icevel.H<yyyy>
Surface temperature (on snow/ice/ocean)
    tice0
    2-D
  K
tice0.H<yyyy>
Sea ice advection (-delta(uh))
   advect
    2-D
 m/s
advect.H<yyyy>
Ocean heat flux used to melt ice, unit: (meter of ice)/s
   oflux
    2-D
 m/s
oflux.H<yyyy>





Sea surface height
     ssh
    2-D
 cm
ssh.H<yyyy>
Ocean surface salinity
    osali1
    2-D
 psu
osali1.H<yyyy>
Ocean salinity of first 10 levels
    osali1_10
    3-D
 psu
osali1_10.H<yyyy>
Ocean surface temperature
    otemp1
    2-D
  C
otemp1.H<yyyy>
Ocean temperature of first 10 levels
   otemp1_10
    3-D
 psu
otemp1_10.H<yyyy>
Ocean velocity at 7.5 m depth, u & v
     uo2
    2-D
 cm/s
uo2.H<yyyy>
Ocean velocity at 7.5 m depth, u & v, daily
     uo2
    2-D
 cm/s
uo2day.H<yyyy>





P-E, NCEP/NCAR Reanalysis forcing
  p-e.m.nmc
   2-D
 m/s
p-e.m.nmc.<yyyy>
 

Methods and data:

SSM/I ice concentration data were assimilated in the TED sea ice model.

Grid:

Grid Parameters:
Grid configuration
Generalized curvilinear coordinate system
Grid Size:  360 x 120
Spatial Coverage
 45o N - 90o N
Spatial Coverage  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 1/1978 to present. Each file contains 12 monthly 2-D or 3-D fields, except hiday.H, snowday.H, and uo2day.H that have daily fields of sea ice thickness (m), snow depth (in meter of water equivalent), and ocean velocity (cm/s) at 7.5 m depth. For daily fields, day 366 in a leap year is not included.

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 velocity and grid information is provided (read_hi_uice.f). An IDL program demonstrating how to read 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 velocity and grid information, can be used to read other scalar and vector 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 snow depth
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
redblue.pro:  IDL routine for setting red and blue 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_120.output: model grid mask; ocean levels > 0, land <= 0

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/IDAO/retrospection.
You can also access the data from here:  ftp://psc.apl.washington.edu/zhang/PIOMAS/data
If you are downloading the data, please e-mail us at zhang@apl.washington.edu we can update you on changes, bugs etc.

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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