Research vessel at the edge of a first year ice floe. Ice classification product showing winter sea ice in the Beaufort Sea. For more information, visit the Jet Propulsion Laboratory and Alaska SAR Facility . We haven't had a space-borne sensor that's capable of providing estimates of thickness distribution. Openings in sea ice occur throughout the year in response to weather conditions like wind direction and speed.
Leads offer navigational windows and provide opportunities for marine mammal and bird migration.
Polynyas, large seasonally reoccurring openings, also support a range of polar marine life. But, because sea ice is an insulator, when a lead or polynya opens, ocean heat flows into the atmosphere, with repercussions to regional climate and the potential to affect longer term climate change. Although leads and polynyas account for only a small percentage of winter sea ice area, these ice openings are estimated to release about half of the total turbulent heat transfer from ocean to atmosphere in winter. Scientists say that the presence or absence of sea ice on the oceans is the most important factor in controlling energy and mass exchange at high latitudes. In addition, older, thicker sea ice is a better insulator than thin, young ice, so that ice thickness bears on the amount of ocean heat released to the polar atmospheres.