The Antarctic Iceberg Tracking Database
1978 & 1992-2012 (Brigham Young University)
Nathan Madsen, Steven Reeves, Keith Stuart, Ben Lambert, Jarom Ballantyne, and David G. Long
Last database update: May 3,  2012 (for current positions click here)
(Iceberg Tracks from 1999-2010)
Using six different satellite scatterometer instruments, we have produced
an iceberg tracking database. The BYU database includes icebergs
identified in enhanced resolution scatterometer backscatter images during
July-Sept. 1978 (from Seasat), July 1996-June 1997 (from NSCAT),
1992-2001 (from ERS-1/2), June 1999-November 2009 (from QuikSCAT), 2008-present (from ASCAT).
Images were obtained from the Scatterometer
Climate Record Pathfinder (SCP) project.
Data sets from six different spaceborne scatterometer
instruments are used to track icebergs. For each data set, resolution enhancement
is performed by BYU's Scatterometer Image reconstruction (SIR) and/or SIR
Filtering (SIRF) algorithms. The scatterometer instruments used in
this study are the Seasat-A Satellite Scatterometer (SASS), the European
Space Agency's Remote Sensing Satellite 1(2) (ERS-1/-2), the NASA Scatterometer
(NSCAT), the QuikSCAT/SeaWinds scatterometer (QSCAT), and the MetOp-A Advanced Scatterometer (ASCAT). The Seasat-A
scatterometer (SASS) was a dual-polarization Ku-band (14.6 GHz) scatterometer
that operated from July to Sept. 1978. Using the SIRF algorithm, Antarctic
images are generated every 12 & 48 days (a longer time is required
for SASS compared to other instruments due to the sampling characteristics
of the nominally 50 km backscatter measurements). The ERS-1/2 spacecraft
carried a C-band (5.3 GHz) active microwave instrument (AMI). The
scatterometer mode provides nominally 50 km resolution data. Using
SIR, Antarctic images are produced every 6 days. The ERS-1/2 scatterometers
operated from Jan. 1992 to Jan. 2001. The NSCAT scatterometer is
a Ku-band Doppler radar similar to SASS, but with dual-side measurement
capability and a dense 25 km resolution sampling. Using SIRF, Antarctic
images were produced every 3 days. The NSCAT mission lasted from
Sept. 1996 to June 1997. QuikSCAT was launched as a ``quick recovery''
mission to help fill the gap created by loss of NSCAT due a satellite failure.
This scatterometer allows daily images of Antarctica to be created.
QuikSCAT operated from July 1999 to November 2009. ASCAT was launched in October of 2006 and is
currently operational. ASCAT
operates at C-Band (5.255 GHz) at vertical polarization only. The
SIRF algorithm applied to ASCAT (Standard BYU
ASCAT Land/Ice Proudcts) generates images from 1 and 2 days of data over Antarctica. Iceberg
tracks for ASCAT have only been done back to November 2009. In the future, the tracks for ASCAT will
go back to the beginning of ASCAT data. This will provide an overlap of two data sets (QuikSCAT and
ASCAT) for a few years (October 2006 to November 2009). A comparative study between the two
instruments is planned.
The initial position for each iceberg is located based on either (1)
a position reported by the National Ice Center (NIC)'s web page (https://www.natice.noaa.gov/products/south_icebergs.html)
or (2) by the sighting of a moving iceberg in a time series of scatterometer
images. From an initial start point, the iceberg is tracked in the
scatterometer image time series. Gaps in the position track result from
missing scatterometer data and from the occasional loss of contrast between
the iceberg and surrounding area during summer months. For each image
a lat/lon position is reported for each iceberg.
Iceberg positions are reported in a separate ASCII text file for each
iceberg. The file name is the same as that of the iceberg. For example
the file "b27.ascat" contains the position track information for B27 from ascat.
A few lines from the b27.ascat file are shown below:
lat: -72.8568 lon: -119.7036 day: 326 2009 file: msfa-a-Ant09-326-326.sir backscat: -7.657
lat: -72.8927 lon: -119.8380 day: 327 2009 file: msfa-a-Ant09-327-327.ave backscat: -9.348
lat: -72.9339 lon: -119.6691 day: 328 2009 file: msfa-a-Ant09-328-328.ave backscat: -8.874
Note that latitude and longitude are specified in decimal degrees with
positive North and East, respectively. The day is specified as: "day of the year" year. The file lists the scatterometer image file from the SCP image set used to track the selected position.  The backscat data
is the backscatter value returned by the scatterometer.
The iceberg database can be obtained via the links shown below.
If desired, data can be imported into Microsoft Excel or other spreadsheet
programs as "space delimited data". Note that ascat data files are in a more abbreviated format than
the other data files.
As of November 2009 ASCAT is being used to track icebergs.  The QuikSCAT data based has been updated and revised through November 23 2009. The QuikSCAT satellite is no longer operational.
DATABASE FILES
ASCAT portion of the database in a gzipped tar file from the SCP web site: icebergDatabase_ascat.tar.gz
QSCAT portion of the database in a gzipped tar file from the SCP web site: icebergDatabase_qscat.tar.gz
OSCAT portion of the database (which is still incomplete) in a gzipped tar file from the SCP web site: icebergDatabase_oscat.tar.gz
All other portions (SASS, ERS-1/2, NSCAT) in a gzipped tar file from the SCP web site: icebergDatabase_other.tar.gz
Individual iceberg tracking files are available for each sensor through
the web links below.
INSTRUMENT
|
TIME PERIOD
|
SASS
|
July 1978 - Sept. 1978
|
ERS-1/2
|
Jan. 1992 - Jan. 2001
|
NSCAT
|
Sept. 1996 - June 1997
|
SeaWinds
|
April 2003 - October 2003
|
QSCAT
|
July 1999 - November 2009
|
ASCAT
|
November 2009 - Present
|
OSCAT
|
November 2010 - Present
|
Related papers:
K.M. Stuart and D.G. Long, "Tracking large tabular icebergs using the SeaWinds Ku-band microwave scatterometer", Deep-Sea Research Part II, to appear,
doi:10.1016/j.dsr2.2010.11.004, 2011.
D.G. Long, Jarom Ballantyne, and C. Bertoia, "Is the Number of Icebergs Really Increasing?" EOS, Transactions of the American Geophysical Union, Vol. 83, No. 42, pp 469 & 474, 15 Oct. 2002.(620 kB
PDF)<
An older report further describing this multidecadal database of Antarctic
icebergs observed with scatterometer data is available in pdf format from
the SCP web site at IcebergReport.
Support from both NASA and NSF is acknowledged.
Last Revised: May 3, 2012
For further information contact:
Dr. David G. Long
long@ee.byu.edu
Professor, Electrical and Computer Eng. Dept. https://www.ee.byu.edu/
Brigham Young University
https://www.byu.edu/
459 Clyde Building
voice: 801-422-4383
Provo, Utah 84602
fax: 801-422-0201
Microwave Earth Remote Sensing (MERS) Lab: https://www.mers.byu.edu/
Scatterometer Climate Record Pathfinder: https://www.scp.byu.edu/
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