AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation

Federal Geographic Data Committee (FGDC) Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Reference_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Mark Fahnestock

Publication_Date: 20061005

Title: AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation

Edition:

Geospatial_Data_Presentation_Form: Digital media

Series_Information:

Series_Name:

Issue_Identification:

Publication_Information:

Publication_Place: Boulder, Colorado USA

Publisher: National Snow and Ice Data Center (NSIDC)

Other_Citation_Details:

Online_Linkage: http://nsidc.org/data/nsidc-0283.html

Description:

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 km^2 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.

Purpose:

Not Available

Supplemental_Information:

REFERENCE: 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.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20040116

Ending_Date: 20041117

Currentness_Reference:Unknown

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Description_of_Geographic_Extent:

Bounding_Coordinates:

West_Bounding_Coordinate: 124.4345

East_Bounding_Coordinate: 124.52668

North_Bounding_Coordinate: -80.77546

South_Bounding_Coordinate: -80.79008

Keywords:

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Theme_Keyword_Thesaurus: GCMD PLATFORM

Theme_Keyword_Thesaurus: GCMD INSTRUMENT

Theme_Keyword_Thesaurus: ANCILLARY KEYWORDS

Theme_Keyword_Thesaurus: ISO TOPIC CATEGORY

Theme_Keyword_Thesaurus: DATA SET LANGUAGE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > ATMOSPHERIC PRESSURE MEASUREMENTS > BAROMETRIC PRESSURE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > AIR TEMPERATURE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE AIR TEMPERATURE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS

Theme_Keyword: EARTH SCIENCE > CRYOSPHERE > SNOW/ICE > SNOW/ICE TEMPERATURE

Theme_Keyword: EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW/ICE TEMPERATURE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND PROFILES > WIND DIRECTION

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND PROFILES > WIND SPEED

Theme_Keyword: EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS > FIRN > TEMPERATURE

Theme_Keyword: WEATHER STATIONS

Theme_Keyword: ANEMOMETERS

Theme_Keyword: PRESSURE SENSORS

Theme_Keyword: THERMOMETERS

Theme_Keyword: WIND PROFILERS

Theme_Keyword: ARGOS > ARGOS DATA COLLECTION AND POSITION LOCATION SYSTEM

Theme_Keyword: Agdc

Theme_Keyword: Air Temperatures

Theme_Keyword: Antarctic

Theme_Keyword: Antarctica

Theme_Keyword: Atmospheric Pressure

Theme_Keyword: Automated Weather Stations

Theme_Keyword: Aws

Theme_Keyword: East Antarctic Plateau

Theme_Keyword: Firn Temperature Measurements

Theme_Keyword: Megadunes

Theme_Keyword: Polar Firn Air

Theme_Keyword: Surface Temperatures

Theme_Keyword: Wind Direction

Theme_Keyword: Wind Speed

Theme_Keyword: CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

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Place_Keyword_Thesaurus: GCMD

Place_Keyword: CONTINENT > ANTARCTICA

Place_Keyword: GEOGRAPHIC REGION > POLAR

Temporal:

Temporal_Keyword_Thesaurus: GCMD

Temporal_Keyword: 10 Minutes

Access_Constraints: Not Available

Use_Constraints:

Not Available

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: NSIDC USER SERVICES

Contact_Position: TECHNICAL CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

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.

Logical_Consistency_Report:

Not Available

Completeness_Report:

Not Available

Lineage:

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Process_Description:

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Process_Date: Unknown

Spatial_Reference_Information:

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Distributor:

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Contact_Organization: NSIDC > National Snow and Ice Data Center

Contact_Person: NSIDC USER SERVICES

Contact_Position: DATA CENTER CONTACT

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Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Distributor:

Contact_Information:

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Contact_Organization: NSIDC_AGDC > NSIDC Antarctic Glaciological Data Center

Contact_Person: NSIDC AGDC USER SERVICES

Contact_Position: DATA CENTER CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Distributor:

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Contact_Organization: NSIDC_USADCC > NSIDC U.S. Antarctic Data Coordination Center

Contact_Person: NSIDC USADCC USER SERVICES

Contact_Position: DATA CENTER CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Resource_Description: NSIDC-0283

Resource_Description: NSIDC-0283

Distribution_Liability:

Not Available

Standard_Order_Process:

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Format_Name: ASCII text

Transfer_Size: 1.48 MB

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http://nsidc.org/antarctica/megadunes/

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Antarctic Megadunes: Research at the Edge of the Earth

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http://nsidc.org/data/nsidc-0282.html

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GPS and GPR Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation

Fees: None

Metadata_Reference_Information:

Metadata_Date: 20061005

Metadata_Review_Date: 20120515

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: GCMD User Support Office

Contact_Organization: NASA Global Change Master Directory

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Not Available

City: Lanham

State_or_Province: MD

Postal_Code: 20706

Country: USA

Contact_Voice_Telephone: Not Available

Contact_Electronic_Mail_Address: gcmduso@gcmd.gsfc.nasa.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time