Recent and Future Changes in the Meteorology of the Pacific Arctic

Abstract

The meteorology of the Pacific Arctic (the Bering Sea through the Chukchi and southern Beaufort Seas) represents the transition zone between the moist and relatively warm maritime air mass of the Pacific Ocean to the cold and relatively dry air mass of the Arctic. The annual cycle is the dominant feature shifting from near total darkness with extensive sea ice cover in winter to solar heating in summer that is equal to that of sub-tropical latitudes. Strong north-south gradients in air temperatures and sea level pressure are typical over the Pacific Arctic giving rise to climatological polar easterly winds (blowing from the east) throughout the year. Localized storms (regions of low sea level pressure) can propagate into the region from the south but high pressure regions are typical, connected to either northeastern Siberia or the southern Beaufort Sea. The northern portion of the Pacific Arctic has participated in the general Arctic-wide warming in all seasons over the last decade while the southern Bering Sea turned to near record cold temperatures after 2006. Future climate changes in the Pacific Arctic will come from shifts in the timing and extent of seasonal sea ice. Based on climate model projections, cold and dark conditions will still dominate over a climate warming scenario in the Bering Sea of +2 °C by 2050. The northern Bering Sea will continue to have extensive sea ice January through April, while the southern shelf will have on average less sea ice than currently observed but with large interannual variability. The largest change has the southern Chukchi Sea shifting from being sea ice free in September and October at present to becoming sea ice free for 5 months from July through November within a decade or two, impacting shipping, oil exploration, and ecosystems.