Comparison Of Measurements And Theory For Backscatter From Bare And Snow-covered Saline Ice

Abstract

Abstract-C-band backscatter measurements were made on artificially grown sea ice at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) during the winters of 1987-1988 and 1988-1989. These measurements were made on smooth, rough, and snow-covered saline ice. The measured U' (6') of smooth saline ice (rms height < 0.05 cm) disagreed with small perturbation method (SPM) surface scattering predictions. Using physical parameters of the ice in a simple layer model, we show that this discrepancy can be explained by scattering from beneath the surface. A thin (7-cm) dry snow cover had a significant influence on backscatter from the smooth ice sheet. This influence was due to scattering from particles within the snow and can be predicted by a commonly used empirical layer model for snow. The results of backscatter measurements of a moderately rough saline ice sheet were found to agree with SPN predictions.

Sensitivity of C-band synthetic aperture radar polarimetric parameters to snow thickness over landfast smooth first-year sea ice

“…6). Brine volume adds an additional volume scattering component to the total scattering (Bredow & Gogineni, 1990). This is due to larger brinecoated snow grains, which can subsequently act as large scattering centers once they become brine coated (Barber & Nghiem, 1999).…”

“…As a result, a number of snow studies have been undertaken using an array of in-situ based Barber, Papakyriakou, & LeDrew, 1994;Barber, Papakyriakou, LeDrew, & Shokr, 1995;Barber, Reddan, & LeDrew, 1995;Iacozza & Barber, 2010;Strum, Holmgren, & Perovich, 2002), laboratory based (Bredow & Gogineni, 1990;Lytle, Jezek, Hosseinmostafa, & Gogineni, 1993) and satellite imagery based techniques (Barber & Nghiem, 1999;Kwork et al, 2011;Markus, Powell, & Wang, 2006;Yackel & Barber, 2007). In-situ and laboratory methods are useful for micro-scale snow analysis but are practically unviable when snow thickness information at large spatial and high temporal scales is required.…”

An ultra-wideband, microwave radar for measuring snow thickness on sea ice and mapping near-surface internal layers in polar firn

“…The range resolution of the system can be verified with data collected over bare sea ice, under the assumption that bare sea ice is a specular target for the radar. Bredow and Gogineni (1990) investigated the backscattering coefficient vs incidence angle of a smooth saline ice sheet at C-band and reported a root-mean-square height of 0.029 cm, which satisfies the Fraunhofer criterion for smoothness at the center frequency of 5 GHz ( Ulaby and others, 1986b). Radar returns from bare sea ice are noticeable due to the increase in side-lobe energy, which is evident for the entirety of the range window, and therefore suitable for deriving the system response.…”

Predicting Melt Pond Fraction on Landfast Snow Covered First Year Sea Ice from Winter C-Band SAR Backscatter Utilizing Linear, Polarimetric and Texture Parameters

“…The accumulation and redistribution of snow on FYI exhibits high spatio-temporal variability [9], and logistical challenges, resulting in a shortage of in-situ data [10]. Snow thickness distributions have been obtained in-situ [9,[28][29][30], using laboratory-based procedures [31,32], and using remote sensing methods based on passive microwave data [33][34][35], frequency-modulated continuous-wave airborne radar returns [36,37] and Synthetic Aperture Radar (SAR) data [7,38,39], and using a combination of active microwave scatterometer and optical data [40].…”