Surface Roughness Measurements on the Western Greenland Ice Sheet

This report summarizes in situ observations of snow surface roughness in relatively benign regions of the western Greenland Ice Sheet. The data were collected in June and August, 1991, June 1992, June 1993 and June 1995. The observations were used to support the interpretation of airborne SAR and laser measurements as well as ERS-1 and JERS-1 spaceborne SAR observations. Surface characterization measurements complemented other, coincident, in situ experiments including C and Ku band surface scatterometer observations, ultra-wideband (operations from 0.5 to 18 GHz) scatterometer measurements, large scale surface topography measured by leveling, and the deployment of radar corner reflectors. This report focuses on snow-surface roughness measurements, both quantitative and anecdotal. Quantitative surface roughness was measured with a large, 1 m long comb gauge and with hand-held comb gauges. Included in the report are qualitative observations of peak-to-peak surface roughness which were frequently commented upon in field notebooks. Also included are numerous photographs. Selecting type areas for measuring roughness was challenging because of the number of surface morphologies distributed in each study areas. A severe limitation of the data is likely to be the short length of the roughness measurements. Sampling length may lead to biased estimates of correlation length. Additional measurements were made of the near surface firn by excavating 1-2 m deep pits. These observations included firn density, grain size, grain shape, temperature, and stratigraphy. 10 m or deeper firn cores were collected from a few sites and analyzed for density, grain size and shape. Surface roughness was frequently measured on ice layers and other inclusions observed in the firn column and some of these data are included for comparison to the snow-surface properties

Broad spectral, interdisciplinary investigation of the electromagnetic properties of sea ice

Journal ArticleThis paper highlights the interrelationship of research completed by a team of investigators and presented in the several individual papers comprising this Special Section on the Office of Naval Research (ONR), Arlington, VA, Sponsored Sea Ice Electromagnetics Accelerated Research Initiative (ARI)

The RADARSAT-1 Antarctic Mapping Project

The University Archives has determined that this item is of continuing value to OSU's history.This report summarizes the motivation, processing procedures and products that were part of the RADARSAT-1 Antarctic Mapping Project (RAMP). RAMP was a collaboration between NASA and the Canadian Space Agency to map Antarctica using the RADARSAT -1 Synthetic Aperture Radar. The project proceeded in two parts. The first part, called Antarctic Mapping Mission -1 that acquired data in 1997, resulted in the first high-resolution radar map of Antarctica. The second part, called the Modified Antarctic Mapping Mission which occurred in 2000, remapped the continent below 80 degrees South latitude and exploited interferometric repeat-pass observations to estimate glacier surface velocities. RAMP project goals and objectives are reviewed here along with several science highlights. These highlights include observations of ice sheet margin change using both RAMP and historical data sets, the discovery of large ice streams in Coates Land, observations of the ice sheet surface-velocity field and changes in the velocity field, and observations of surface change using radar coherence. RAMP data products are summarized and a tabulated list of data products is appended to this report. The appendix also lists all of the partner organizations, including the Alaska Satellite Facility (ASF) DAAC, who have received a copy of the complete data set.NASA Pathfinder ProgramNASA Polar Oceans and Ice Sheets ProgramOffice of Polar Programs, National Science FoundationCanadian Space Agenc

Determination of Absolute Gravity at BPRC/US Polar Rock Repository

We determined absolute gravity at a base station located in the north-east corner of the U.S. Polar Rock Repository based on two field surveys conducted in summer 2005. We used a CG-5 Scintrex Autograv System for our measurements. The meter can measure relative gravity to a precision of 0.001 mGal. To find the absolute gravity we visited three tie-point sites, one located at the OSU Main Library, one in downtown Columbus and one south-west of town near Bolton Airfield. The sites were set up by the NOAA and NGS and absolute gravity was determined using a relative gravimeter (Lacoste-Romberg) which in turn was tied back to a site of known gravity. An absolute gravity measurement was conducted by NOAA-NGS in summer 2005 at OSU, in Mendenhall Laboratory. At each of the sites, we recorded a series of gravity measurements. These were subsequently used to calculate absolute gravity at the rock repository base station where measurements were taken at the start and end of the survey. We found the absolute gravity at the base station to be 980082.070 mGal with an error of about 0.035 mGal. This report is a summary of this investigation

Radar and Snow Structure Studies in the Percolation Zone of the Greenland Ice Sheet: A Data Report on the 1993 Field Season at Dye-2

From June 18 to July 12, 1993, a Byrd Polar Research Center team undertook radar and snow physical properties studies near Dye-2, in the percolation zone of Greenland's ice sheet. These studies were intended to advance our understanding of the microwave scattering properties of the ice sheet, in order to better interpret satellite remote sensing signals for mass balance and climate studies. This report summarizes the experiments performed and the data collected. Table I summarizes a list of our measurement objectives. In general terms, our work at Dye-2 consisted of making radar observations of the snow at Ku-band (13.5 GHz) and a variety of incidence angles. The radar frequency is the same as that of the radar altimeter aboard the ERS-1 satellite. In conjunction with the radar observations, we dug pits in the snow and recorded physical properties such as snow stratigraphy, density, and grain sizes. In section 2 we present a map of the camp and experiment sites. In sections 3 and 4 we describe the pit and radar studies in detail. Finally, section 5 is a detailed chronology of the field season

Jakobshavn Glacier, west Greenland: 30 years of spaceborne observations

This is the published version, also available here: http://dx.doi.org/10.1029/98GL01973.Early 1960's reconnaissance satellite images are compared to more recent image and map data in an interannual and seasonal study of West Central Greenland margin fluctuations. From 1962 to 1992, ice sheet margins to the north and south of Jakobshavn Glacier retreated despite a decline in average summer temperatures. The retreat may be reversing along the southern flank of the ice stream where regional mass balance estimates are positive. From 1950 to 1996, the terminus of Jakobshavn Glacier seasonally fluctuated ∼2.5 km around its annual mean position. The total calving flux during the summer is more than six times that during winter. We identified that summer melting and the break-up of sea ice and icebergs in the fjord are important in controlling the rate of iceberg production. If correct, calving rates may be expected to increase should climate become warmer in the near future