Recent Variability in Sea Ice Cover, Age, and Thickness in the Pacific Arctic Region

Abstract

Over the past several decades, there has been a fundamental shift in sea ice cover, age, and thickness across the Pacific Arctic Region (PAR). Satellite data reveal that trends in sea ice cover have been spatially heterogeneous, with significant declines in the Chukchi Sea, slight declines in the Bering Strait region, yet increases in the northern Bering Sea south of St. Lawrence Island. Declines in the annual persistence of seasonal sea ice cover in the Chukchi Sea and Bering Strait region are due to both earlier sea ice breakup and later sea ice formation. However, increases in the persistence of seasonal sea ice cover south of St. Lawrence Island occur primarily owing to earlier sea ice formation during winter months. Satellite-based observations of sea ice age along with modeled sea ice thickness provide further insight into recent sea ice variability throughout the PAR, with widespread transitions towards younger, thinner ice. Investigation of sea ice cover, age, and thickness in concert provides critical insight into ongoing changes in the total volume of ice and therefore the future trajectory of sea ice throughout the PAR, as well as its likely impacts on ecosystem productivity across all trophic levels.