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Hierarchy implies that the study of sea ice can be divided into analysis of subsets of processes based on scale and their interaction with adjacent scales. We apply these concepts to regional sea ice dynamics. The apparent self‐similar property of ice floes seen in aircraft or satellite images argues for an aggregate nature of sea ice, that viscouslike regional behavior arises from discrete floe interactions. However, for some regions and some times, characteristic behavior, where lead patterns seen in basin‐wide advanced very high resolution radiometer images appear to be related to coastal orientation hundreds of kilometers away, suggests that small regional scale processes O(10 km) and discontinuities in the velocity or stress state along boundaries can affect the larger‐scale sea ice distribution and dynamics O(500 km). Thus sea ice displays both aggregate type behavior and discontinuous type behavior based on the history of forcing and shape of the enclosing basin. The appropriate matching of atmospheric processes to sea ice processes in air‐ice interaction is through the sea ice deformation field rather than the response of ice velocity to the local wind. This is because atmospheric forcing and sea ice deformation have matching energetic scales at several hundred kilometers and timescales of days. An example of northerly winds during the April 1992 Arctic Leads Experiment period suggests discontinuous type behavior upwind of the Alaska coast followed by a general opening behavior with easterly winds. There appear to be natural scale divisions between climate scale sea ice processes of O(100–300 km) which resolve aggregate behavior, regional scale O(10–50 km) which is necessary to resolve observed shearing behavior, and the floe scale O(1 km). Because the climate scale is two levels removed from the floe scale, care must be exercised in using ice properties from the floe scale in climate scale models; ice strength is an example of such a scale dependent parameter.

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Motivated by the importance of quantifying the regional surface heat balance over Arctic sea ice in studying climate processes, Lindsay and Rothrock (1994) developed a methodology for computing regional surface sensible heat fluxes using readily available advanced very high resolution (AVHRR) IR satellite imagery. Their technique is based upon the determination of the pixel‐by‐pixel sea ice surface temperature from which estimates of sensible heat fluxes are then made. We compare the sensible heat fluxes over the Beaufort Sea computed using their methodology with those measured by a gust probe system on the National Oceanic and Atmospheric Administration P‐3 aircraft on April 18, 1992, during the Leads Experiment. We use an AVHRR image recorded during the P‐3 flight at 2303 UTC. We show that individual lead heat fluxes can be large, 115 W m−2 for 1‐km average fluxes obtained from flight legs that included a 300‐m‐wide lead, but that regional values of sensible flux over 50–200 km of sea ice were small and positive, ∼8 W m−2. The sensible heat flux computed from the P‐3 showed that a value of CS = 1.1×10−3, where CS is the heat transfer coefficient relative to 10 m, is appropriate for the spring Beaufort Sea. We suggest that more realistic winds derived, for example, from the National Meteorological Center sea level pressure analyses be used instead of the constant value of 5 m s−1 now employed by Lindsay and Rothrock. We also found that the maximum value of ΔT, the difference between air and surface temperature, used in the calculation of sensible heat flux using the Lindsay and Rothrock technique was underestimated by a factor of 1.9 when compared with direct measurements. Use of this ΔT correction factor, synoptic scale winds, and the calculated value of CS gave a good comparison between the AVHRR approach and aircraft fluxes measured over the region. The effective regional momentum drag coefficient CD relative to 10 m was 2.1×10−3, typical of Arctic pack ice.