Ice conditions at the Surface Heat Budget of the Arctic (SHEBA) site in spring 1998 included new leads, ridges, first-year ice, and multiyear ice with varying snow conditions. To assess the effects of these variations in surface conditions on the aggregate-scale energy budget during April through early May, an instrumented sled-mounted platform was used to collect data in conjunction with other field instruments as well as aircraft and satellite overpasses. Observations collected using this platform in different configurations included radiometric skin temperature, air temperature, and surface reflectance recorded at 1-second or 10-second intervals. Measurements were taken along transects covering several kilometers in the vicinity of the SHEBA camp, along short transects over ridges, and at monitoring sites over re-freezing leads. The mobile platform nstrumentation includes a KT-19 radiometer, LI-COR pyranometer, and thermistor supported by a modified data logger, battery pack, and solar panels. Instruments are mounted from an extendable boom at a typical height of 1.5 m from the surface, and towed behind a snow machine to acquire data along transects or positioned at fixed locations. The radiometer and pyranometer view the surface at 90 degrees (e.g., nadir-viewing) or 30 degrees from nadir. The instruments could also be removed from the sled to traverse areas not accessible by snow machine. Additional observations collected at SHEBA in conjuction with the mobile platform included surface albedo, snow and ice physical temperatures, snow conditions, and snow temperature profiles.
Here, we review the characteristics of the mobile platform and summarize the spatial and temporal variability of skin temperature, air temperature, and reflectance as a function of surface and meteorological conditions. Comparisons are made between the surface measurements and areally-integrated satellite retrievals from Advanced Very High Resolution Radiometer (AVHRR) Polar Pathfinder products and the Special Sensor Microwave/Imager. Based on the mobile platform observations of the evolution of refreezing leads, we also consider how factors such as frost flowers and frazil ice formation affect mapping of lead fraction from satellite data. We conclude by suggesting improvements to the mobile platform and discussing future applications.