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Characterization of Leads at SHEBA Derived From Passive Microwave Observations |
University of Colorado
tschudi@raf.atd.ucar.edu
The Airborne Imaging Microwave Radiometer (AIMR) was mounted on the underside of the NCAR/NSF C-130 flown during May and July 1998 during SHEBA. The AIMR is a passive microwave, cross-track scanner that operates at 37 and 90 GHz. Post-processing by NCAR's Atmospheric Technology Division corrects the data for aircraft attitude and produces vertical and horizontal polarization datasets at both frequencies.
Patterns were designed and flown to maximize the resolution, while providing continuous coverage of the surface in the vicinity of the Des Groseilliers. To meet sampling requirements for SHEBA, the patterns covered 20x20 and 50x50 km boxes.
During May, most leads were covered with thin ice, which exhibits a higher microwave brightness temperature than the surrounding pack ice. This provides a useful mechanism to identify leads and quantify their distribution, e.g. lead fraction, width and orientation. Temporal and spatial variability of these lead parameters is examined.
