NSIDC-0283 AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation Mark Fahnestock AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation 2006-10-05 Boulder, Colorado USA NSIDC: National Snow and Ice Data Center http://nsidc.org/data/nsidc-0283.html http://dx.doi.org/10.7265/N5K935F3 Investigator Mark Fahnestock mark.fahnestock@unh.edu 1 603 862-0322

University of New Hampshire

Institute for the Study of Earth, Oceans, and Space

University of New Hampshire

39 College Road

Durham NH 03824-3525 USA Investigator Ted Scambos scambos@nsidc.org

University of Colorado

Cooperative Institute for Research in Environmental Science

National Snow and Ice Data Center

CIRES, 449 UCB

Boulder CO 80309-0449 Investigator Terry Haran

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

Boulder CO 80309-0449 Investigator Rob Bauer bauerr@kryos.colorado.edu 1 303 492 2378

University of Colorado

Cooperative Institute for Research in Environmental Sciences

University of Colorado

CIRES 449 UCB

Boulder CO 80309 USA Technical Contact NSIDC User Services nsidc@nsidc.org 1 303 492-6199 x 1 303 492-2468 x

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

Boulder CO 80309-0449 USA EARTH SCIENCE Atmosphere Atmospheric Pressure Atmospheric Pressure Measurements Barometric Pressure EARTH SCIENCE Atmosphere Atmospheric Temperature Air Temperature EARTH SCIENCE Atmosphere Atmospheric Temperature Surface Air Temperature EARTH SCIENCE Atmosphere Atmospheric Winds Surface Winds EARTH SCIENCE Atmosphere Atmospheric Winds Wind Profiles Wind Direction EARTH SCIENCE Atmosphere Atmospheric Winds Wind Profiles Wind Speed EARTH SCIENCE Cryosphere Glaciers/Ice Sheets Firn Temperature EARTH SCIENCE Cryosphere Snow/Ice Snow/Ice Temperature EARTH SCIENCE Terrestrial Hydrosphere Snow/Ice Snow/Ice Temperature Climatology/Meteorology/Atmosphere 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 ANEMOMETERS ARGOS ARGOS Data Collection and Position Location System PRESSURE SENSORS THERMOMETERS WIND PROFILERS WEATHER STATIONS 2004-01-16 2004-11-17 complete -80.79008 -80.77546 124.4345 124.52668 2884 meters CONTINENT ANTARCTICA 00:10:00 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. English NSIDC_AGDC NSIDC National Snow and Ice Data Center http://nsidc.org Data Center Contact NSIDC User Services nsidc@nsidc.org 1 303 492-6199 1 303 492-2468

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

Boulder CO 80309-0449 USA NSIDC_AGDC NSIDC Antarctic Glaciological Data Center http://nsidc.org/agdc/ Data Center Contact NSIDC AGDC User Services nsidc@nsidc.org 1 303 492-6199 1 303 492-2468

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

Boulder CO 80309-0449 USA NSIDC_USADCC NSIDC U.S. Antarctic Data Coordination Center http://nsidc.org/usadcc/ Data Center Contact NSIDC USADCC User Services nsidc@nsidc.org 1 303 492-6199 1 303 492-2468

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

Boulder CO 80309-0449 USA FTP 1.48 MB ASCII Text http://nsidc.org/data/docs/agdc/nsidc0283_fahnestock/dunes_area_location.jpg Site Location 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.

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.

VIEW PROJECT HOME PAGE http://nsidc.org/antarctica/megadunes/ Antarctic Megadunes: Research at the Edge of the Earth VIEW RELATED INFORMATION http://nsidc.org/data/nsidc-0282.html GPS and GPR Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation AMD/US CEOS IDN DIF 9.7 2006-10-05 2013-03-18 Added DOI