BESTMAS results

Model and Schematic Circulation - Zhang - Stabeno etal 1999

Inset map shows schematic Bering Sea Circulation from Stabeno et al 1999. Rest of figure shows simulated Bering Sea surface velocity for August 2005 from the BESTMAS high resolution ocean-ice model (see below for details).

Changing Sea-ice and the Bering Sea Ecosystem
Results from the BESTMAS coupled ice-ocean model of the Bering Sea

Jinlun Zhang
(zhang@apl.washington.edu)
(homepage)

Rebecca Woodgate
(woodgate@apl.washington.edu)
(home page)

Funded by NSF Arctic Natural Sciences (grant ARC-0611967)

Part of NSF's BEST (Bering Sea Ecosystem Study) Project

Polar Science Center, Applied Physics Laboratory,
University of Washington
1013 NE 40th Street, Seattle, WA 98105, U.S.A.

The BESTMAS (Bering Ecosystem STudy ice-ocean Modeling and Assimilation System) is a coupled ice-ocean model focused on the Bering Sea, run at ~ 5 km resolution. For more details, see this link. On this page, you will find:

Movies of the Bering Sea Ice-Ocean fields as simulated by BESTMAS:
- monthly-mean velocity at 15m depth (Jan 2002 - Dec 2006)
- March sea-ice extent with observed ice edge (1970-2006)
- monthly-mean sea-ice extent with observed ice-edge (Jan 2002 - Dec 2006)

Model Data Output for:
- sea-ice thickness
- snow depth
- sea surface height
- ocean temperature at 5m depth
- ocean velocity at 15m depth
    (including some plotting routines)

BESTMAS MOVIES

Monthly-mean velocity at 15m depth
(Jan 2002 - Dec 2006)

March sea-ice extent with observed ice edge (1970-2006)

Monthly-mean sea-ice extent with observed ice-edge
(Jan 2002 - Dec 2006)

BESTMAS MODEL DATA OUTPUT
BESTMAS Data and supporting programs are available from our ftp site.

VARIABLES:

Variable	Variable name	Dimension	Unit	File name
Sea ice thickness	heff	2-D	m	heff_167_233.H<yyyy>
Snow depth (water equivalent) *	snow	2-D	m	snow_167_233.H<yyyy>
Ocean temperature at 5 m	otemp1	2-D	C	otemp1_167_233.H<yyyy>
Ocean velocity at 15 m	uo2	2-D	m/s	uo2_167_233.H<yyyy>
Sea surface height	ssh	2-D	cm	ssh_167_233.H<yyyy>

* 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 sea ice model.

GRID:

Model grid configuration	Generalized curvilinear coordinate system
Model grid size (for the whole model domain):	600 x 300
Model spatial coverage (for the whole model domain):	35 degree N. The model grid domain is shown here
Data grid size (only for Bering Sea):	167 x 233
Data spatial coverage (only for Bering Sea):	Bering Sea.
lon and lat for scalar fields (on data grid):	grid.dat.rot_beringonly
lon and lat for vector fields (on data grid):	grid.dat.pop_beringonly
angle between latitude line and grid cell x-coordinate line (on data grid):	alpha.fortran.dat_beringonly

TEMPORAL COVERAGE:
Currently monthly data from 1/1970 to 12/2006. Each file contains 12 monthly 2-D fields.

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_uo_167_233.f). An IDL program demonstrating how to read (and plot) scalar fields and grid information is also provided (read_draw_hi_167_233.pro). Another IDL routine (read_draw_uo_167_233.pro) is provided to read vector fields and vector grid information. It also plots ocean velocity at 15 m depth on a spherical coordinate system using the angle between the latitude line and the grid cell x-coordinate line (alpha.fortran.dat_beringonly). 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_uo_167_233.f : FORTRAN program to read sea ice thickness and grid information, can be used to read other scalar fields
read_draw_hi_167_233.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_uo_167_233.pro : IDL program to read and plot ocean velocity, can be used to read and plot other vector fields such as sea ice 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
levels_25_t_167_233: model grid mask; ocean levels > 0, land < 0

OTHER WAYS TO ACCESS THE MODEL OUTPUT:
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/BEST.
You can also access the data from here: ftp://psc.apl.washington.edu/zhang/Bering
If you are downloading the data, please e-mail us at zhang@apl.washington.edu, so we can update you on changes, bugs etc.

CITATION:
Please use the following citation to reference these 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.

OTHER MODEL DATA SETS OF INTEREST:
Zhang, Rothrock and Steele - Projections of an Ice-Diminished Arctic Ocean - website and ftpsite

For use of any of these figures, or if you have any questions, please contact Jinlun Zhang (zhang@apl.washington.edu).

We gratefully acknowledge financial support for this work from the National Science Foundation (NSF).
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