Search Help
Global Change Master Directory (GCMD)
AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation
Entry ID: NSIDC-0283


Summary
Abstract: The Antarctic megadune research was conducted during two field seasons, one in November 2002 and the other during the period of December 2003 through January 2004. The megadune field site is located on the East Antarctic Plateau, southeast of Vostok station. The objectives of this multi-facetted research are 1) to determine the physical characteristics of the firn across the dunes including typical climate indicators such as stable isotopes and major chemical species and 2) to install instruments to measure the time variation of near-surface wind and temperature with depth, to test and refine hypotheses for megadune formation. It is important to improve our current understanding of the megadunes because of their extreme nature, their broad extent, and their potential impact on the climate record. Megadunes are a manifestation of an extreme terrestrial climate and may provide insight on the past terrestrial climate or on processes active on other planets.

Snow megadunes are undulating variations in accumulation and surface texture with wavelengths of 2 to 5 km and amplitudes up to 5 meters. The features cover 500,000 km2 of the East Antarctic plateau, occurring in areas of moderate regional slope and low accumulation on the flanks of the ice sheet between 2500 and 3800 meters elevation. Landsat images and aerial photography indicate the dunes consist of alternating surfaces of glaze and rough sastrugi, with gradational boundaries. This pattern is oriented perpendicular to the mean wind direction, as modeled in katabatic wind studies. Glazed surfaces cover the leeward faces and troughs; rough sastrugi cover the windward faces and crests. The megadune pattern is crossed by smooth to eroded wind-parallel longitudinal dunes. Wind-eroded longitudinal dunes form spectacular 1-meter-high sastrugi in nearby areas.

This data set contains automated weather station (AWS) data from two sites. The Mac site was oriented on the rough sastrugi-covered windward face and the Zoe site was on the glazed leeward face. The AWSs collected data throughout the year from 16 January 2004 to 17 November 2004. Investigators received data from the two field sites via the ARGOS Satellite System (http://www.argosinc.com/). Data are provided in space-delimited ASCII text format and are available via FTP.

Related URL
Link: View Related Information
Description: Documentation


Link: View Related Information
Description: FTP


Link: View Related Information
Description: Antarctic Megadunes: Research at the Edge of the Earth


Link: View Related Information
Description: GPS and GPR Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation

Geographic Coverage
 N: -80.77546 S: -80.79008  E: 124.52668  W: 124.4345
 Max Altitude: 2884 METERS

Data Set Citation
Dataset Creator: Fahnestock, M., T. Scambos, T. Haran, and R. Bauer.
Dataset Title: AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation
Dataset Series Name: NSIDC-0283
Dataset Release Date: 2006-10-05
Dataset Release Place: Boulder, Colorado USA
Dataset Publisher: NSIDC: National Snow and Ice Data Center
Version: 1
Online Resource: http://www.usap-dc.org/view/dataset/609283


Temporal Coverage
Start Date: 2004-01-16
Stop Date: 2004-11-17


Location Keywords
CONTINENT > ANTARCTICA


Data Resolution
Temporal Resolution: 10 minute


Science Keywords
ATMOSPHERE >ATMOSPHERIC PRESSURE >ATMOSPHERIC PRESSURE MEASUREMENTS    [Definition]
ATMOSPHERE >ATMOSPHERIC TEMPERATURE >SURFACE TEMPERATURE >AIR TEMPERATURE    [Definition]
CRYOSPHERE >SNOW/ICE >SNOW/ICE TEMPERATURE    [Definition]
TERRESTRIAL HYDROSPHERE >SNOW/ICE >SNOW/ICE TEMPERATURE    [Definition]
CRYOSPHERE >GLACIERS/ICE SHEETS >FIRN    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >SURFACE WINDS    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >WIND PROFILES    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >WIND PROFILES >WIND DIRECTION PROFILES    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >WIND PROFILES >WIND VELOCITY/SPEED PROFILES    [Definition]


Platform
WEATHER STATIONS    [Information]


Instrument
ANEMOMETERS    [Information]
ARGOS >ARGOS Data Collection and Position Location System    [Information]
PRESSURE SENSORS
THERMOMETERS    [Information]
WIND PROFILERS    [Information]


Quality
The 10 meter firn temperature reading did not work much of the time at the Zoe site (mostly not a number (NAN) values). Not all ARGOS satellite passes caught both a Block 1 and a Block 2 corresponding to the same set of measurements, so they are not coincident measurements unless their julian day values match to within about 0.007 days (about 10 minutes). There are a few spurious points because of the communication link: sometimes the data logger and satellite transmitter would get out of sync, and values ended up in the wrong columns, etc. Investigators filtered out the obvious spurious values, but a few still exist in the data.

Investigators estimated the wind direction margin of error at the Mac site to be �1 degree clockwise from true north with no measurable offset. They estimated wind direction margin of error at the Zoe site to be � 4 degrees clockwise from true north, but believe the measurements appeared to be approximately 4 degrees too high.


Keywords
AGDC
Air Temperatures
Antarctic
Antarctica
Atmospheric Pressure
Automated Weather Stations
AWS
East Antarctic Plateau
Firn Temperature Measurements
Megadunes
Polar Firn Air
Surface Temperatures
Wind Direction
Wind Speed


Data Set Progress
COMPLETE


Originating Center
AGDC


Data Center
NSIDC Antarctic Glaciological Data Center    [Information]
Data Center URL: http://nsidc.org/agdc/

Data Center Personnel
Name: AGDC USER SERVICES
Phone: 1-303-492-6199
Fax: 1-303-492-2468
Email: nsidc at nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA



Distribution
Distribution_Media: FTP
Distribution_Size: 1.48 MB
Distribution_Format: ASCII Text (.txt)


Personnel
MARK FAHNESTOCK
Role: INVESTIGATOR
Phone: 1-603-862-0322
Email: mark.fahnestock at unh.edu
Contact Address:
University of New Hampshire
39 College Road
City: Durham
Province or State: NH
Postal Code: 03824-3525
Country: USA


TED SCAMBOS
Role: INVESTIGATOR
Email: scambos at nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
City: Boulder
Province or State: CO
Postal Code: 80309-0449


TERRY HARAN
Role: INVESTIGATOR
Contact Address:
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449


ROB BAUER
Role: INVESTIGATOR
Phone: 1-303-492 2378
Email: bauerr at kryos.colorado.edu
Contact Address:
University of Colorado
CIRES 449 UCB
City: Boulder
Province or State: CO
Postal Code: 80309
Country: USA


NSIDC USER SERVICES
Role: TECHNICAL CONTACT
Phone: 1-303-492-6199
Fax: 1-303-492-2468
Email: nsidc at nsidc.org
Contact Address:
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA


Publications/References
Albert, M. R., C. A. Shuman, Z. R. Courville, R. Bauer, M. A. Fahnestock, and T. A. Scambos. 2004. Extreme firn metamorphism: impact of decades of vapor transport on near-surface firn at a low-accumulation glazed site on the East Antarctic Plateau. Annals of Glaciology 39: 73-78.

Campbell Scientific, Inc. 2002. CR10X Measurement and Control Module Operator's Manual.

Courville, Z. R., M. R. Albert, and J. Severinghaus. 2002. Firn physical characteristics and impact on interstitial convection and diffusion in the megadunes of East Antarctica. Eos. Trans. AGU 85(47). Fall Meeting Suppl., Abstract C31C-06.

Courville, Z. R., M. R. Albert, M. A. Fahnestock, and L. Cathles. 2005. Impact of accumulation rate on firn properties. Eos. Trans. AGU 86(52). Fall Meeting Suppl., Abstract C21B-1108.

Courville, Z. R., M. Albert, M. Fahnestock, L. M. Cathles. 2006. Impact of accumulation hiatus on the physical properties of firn at a low accumulation site. Journal of Geophysical Research. In review.

Fahnestock, M. A., T. A. Scambos, C. A. Shuman, et. al. 2000. Snow megadune fields on the East Antarctic Plateau: extreme atmosphere-ice interaction. Geophysical Research Letters 27(22): 3719-3722.

Fahnestock, M. A., C. A. Shuman, M. R. Albert, and T. A. Scambos. 2002. Satellite, observational, meteorological and thermal records from two sites in the Antarctic megadunes stability of atmospheric forcing, thermal cracking, and the seasonal evolution of the thermal profile. Eos. Trans. AGU 85(47). Fall Meeting Suppl., Abstract C31C-03.

Fahnestock, M. A., C. A. Shuman, T. A. Scambos, M. R. Albert, T. Haran, Z. R. Courville, and R. Bauer. 2005. Mapping Antarctic megadunes and other accumulation-related features on the East Antarctic Plateau. Eos. Trans. AGU 86(52). Fall Meeting Suppl., Abstract C13A-06.

Frezzotti, M., S. Gandolfi, F. La Marca, and S. Urbini. 2002. Snow dunes and glazed surfaces in Antarctica: new field and remote sensing data. Annals of Glaciology 34: 81-88.

Frezzotti, M., S. Gandolfi, and S. Urbini. 2002. Snow megadunes in Antarctica: sedimentary structure and genesis. Journal of Geophysical Research 107(D18), 4344: doi:10.1029/2001JD000673.

Kawamura, K., and J. P. Severinghaus. 2005. Krypton and Xenon as indicators of convective zone thickness in firn at Megadunes, Antarctica. Eos. Trans. AGU 86(52). Fall Meeting Suppl., Abstract PP33C-1590.

Scambos, T. A., M. A. Fahnestock, C. A. Shuman, and R. Bauer. 2002. Antarctic megadunes: characteristics and formation. Eos. Trans. AGU 85(47). Fall Meeting Suppl., Abstract C31C-04.

Suchdeo, V. P., C. A. Shuman, T. A. Scambos, M. A. Fahnestock, M. R. Albert, and R. Bauer. 2002. Precise elevation profiles across Antarctic megadunes. Eos. Trans. AGU 85(47). Fall Meeting Suppl., Abstract C33C-0357.

Suwa, M., and J. Severinghaus. 2002. Firn density profile at Megadunes, East Antarctica, calls for an improved densification model for low accumulation sites. Eos. Trans. AGU 85(47). Fall Meeting Suppl., Abstract C33C-0359.
Extended Metadata Properties
(Click to view more)

Creation and Review Dates
DIF Creation Date: 2006-10-05
Last DIF Revision Date: 2018-02-05



-->