Access Information

Introduction

The AARI data set, in SIGRID format, is distributed via ftp. The data files contain sea ice parameters (ice concentration, stage of development, and form of ice) for the Eurasian portions of the Arctic Ocean.

Data Set Location

The AARI data set is provided in two separate packages: one for use in a UNIX environment, the other for use in an MS-DOS environment. The UNIX and MS-DOS packages can be acquired from the NSIDC anonymous ftp server, sidads.colorado.edu. The UNIX version of the package is located in the directory /pub/DATA_SETS/DATA/AARI/UNIX; the MS-DOS version of the package is located in the directory /pub/DATA_SETS/DATA/AARI/DOS.

Description of UNIX Package

The AARI data files packaged for use on UNIX platforms are stored in compressed tar files. The data files are grouped in tar files by the sector reference (Eastern, Western, or the entire polar basin):

aari-east.tar.Z	Contains files for the Eastern sector, which
		covers (although not consistently) the Beaufort,
	        Chukchi, Berring and East Siberian Seas. The tar file	
		contains data for the period 1968-1971 and
		1973-1990. 
				

aari-west.tar.Z	Contains files for the Western sector, which
	        covers (although not consistently) the Laptev,
	  	Kara, and Barents Seas. The tar file
		contains data for 1953 through 1971 and 1973
		through 1990.

aari-72.tar.Z	Contains files which combine both the
		Eastern and Western sectors. The tar file contains
		data for 1972, the only year for which combined
		sectors are available.

Naming Convention for the AARI Data Files Packaged for UNIX

Names of the AARI data files grouped in the compressed tar files for UNIX are designed to indicate the sector, year, month, and a date attribute indicating the ten-day period within the month over which the data going into the chart were compiled. The 10-day periods are the same for every month: they cover the dates 1-10, 11-20, and 21-30 or 31 (except 28/29 for February). If the date attribute is in the first part of the 10-day interval (1-5 for date intervals 1-10, 11-15 for date intervals 11-20, and 21-25 for date intervals 21-28, 21-29, 21-30, and 21-31) then the chart contains some information which was acquired over the entire 10-day period. If the date attribute isin the second part of the 10-day interval (6-10 for intervals 1-10, 16-20 for intervals 11-20, and 26-31 for the last period of a given month), approximately 75 percent of the chart contains information from the second half of the 10-day period and 25 percent of the chart contains information from the first half of the 10-day period.

Following are examples of hte file naming convention. Remember that the date attribute gives the 10-day period for which data were compiled, not the date on which all chart data were collected.

e730218.aari 	Eastern sector, 18 February 1993
w811015.aari	Western sector, 15 October 1981
a720506.aari	eastern and western Arctic, 6 May 1972

Description of Sample Software Accompanying the UNIX Package

A detailed description of the software which accompanies the UNIX package is located in the anonymous ftp directory (pub/DATA_SETS/DATA/AARI/UNIX). The name of the file is aari-unix-sw.doc. The files containing the software distributed with the AARI data set for the UNIX environment are:

strip_geog.c	C source code which can be compiled
		using a UNIX C compiler. 

aari_idl.tar.Z	A set of IDL routines which can be
		used to read and visualize the AARI
		data. The compressed tar file contains
		the following files:
					
		aari.pro
		aari_colortable.pro
		legend_conc.pro
		legend_form.pro
		legend_stage.pro
		read_aari_img.pro

aari-unix-sw.doc	Documentation describing the usage of the 
			UNIX software utilities.

aari-coding.doc	Documentation describing the digitization and
		coding procedures used by AARI to produce the
		digitized sea ice charts.

Description of MS-DOS Package

The AARI data files packaged for use in an MS-DOS environment are stored in container files using the public domain utility PKZIP. The data files are grouped in .ZIP file by the sector reference (Eastern, Western, or the entire polar basin) and by the year referenced by the AARI data file. For example:

E67SIG.ZIP	Contains files for the Eastern sector, where
		the origin of the chart usually starts at
		108 degrees east longitude. The .ZIP file
		contains data for the year 1967.

w90SIG.ZIP	Contains files for the Western sector, where
		the origin of the chart usually starts at
		24 degrees west longitude. The .ZIP file
		contains data for the year 1990.

A72SIG.ZIP	Contains files which combine both the
		Eastern and Western sectors. The origin of
		the chart usually starts at 24 degrees west
		longitude. The .ZIP file contains data for
		the year 1972.

Naming Convention for the AARI Data Files Packaged for MS-DOS

Names of the AARI data files grouped in the .ZIP files for MS-DOS are designed to indicate the sector, year, month, and day of the data reference in the data file. For example:

E730218.SIG	Eastern sector, 18 February 1993
W811015.SIG	Western sector, 15 October 1981
A720506.SIG	eastern and western Arctic, 6 May 1972

Description of Sample Software Accompanying the MS-DOS Package

A detailed description of the software which accompanies the MS-DOS package is located in the anonymous ftp directory (pub/DATA_SETS/DATA/AARI/DOS). The name of the file is AARI-SW.DOC. The files containing the software distributed with the AARI data set for the MS-DOS environment are:

STRIPSIG.C	C source code which can be compiled
		using an MS-DOS C compiler.

STRIPSIG.EXE	Executable binary compiled using 
		MS-DOS C compiler.

PKUNZIP.EXE	Executable DOS utility to "un-zip" the
		.ZIP container files.

AARI-SW.ZIP	A .ZIP file containing software developed
		and compiled at AARI. The executable binary
		file (SIMAX.EXE) contained in the .ZIP file
		can be used to visualize AARI data. The
		.ZIP file contains the following files:
				
		ALL.BAT
		LINK.BAT
		COAST.BIT
		SIMAX.EXE
		GRFKBD.FD
		GRFKBD.FI
		SIMAX.FOR
		SUB_ARG.FOR
		SUB_DAT.FOR
		SUB_RAM.FOR
		SUB_VGA.FOR
		W820312.SIG
		W820312.LST
 
AARI-SW.DOC	Documentation describing the usage
		of the UNIX software utilities.
 
CODING.DOC	Documentation describing the digitization and
		coding procedures used by AARI to produce the
		digitized sea ice charts.

NSIDC User Services Contact Information

Please direct all inquiries about the data set to NSIDC User Services:

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org