FY 1997

Studying arctic sea ice at two scales provides more accurate picture

Overland, J.E., and W. Weeks

Eos Trans. AGU, 77(50), 501, 505–506, doi: 10.1029/96EO00330 (1996)

Historically, sea ice has been viewed on distinct scales depending on the problem under study. Researchers rarely investigated the knowledge needed to bridge these scales. Two developments, however, are changing the status quo. Ice motions on scales of 5 km can now be observed using all-weather data collected by synthetic aperture radar (SAR) sensors on satellites combined with automated image analysis procedures. Second, the increased availability of high-speed computer resources has made it feasible to resolve spacings of 10 km even in numerical models of the Arctic basin. In short, we now can observe and model pack ice on scales that approximate its granularity. Preliminary results using these new abilities confirm that sea ice behaves like a hardening plastic material on scales of 1-100 km. These results pose another question: what additional information and new approaches are needed to bridge the hierarchical gaps between small-scale properties as measured within an ice floe, larger-scale geophysical processes that involve floe-floe interactions, and ultimately climate processes?