Abstract:

Recent evidences show that a rapid change has occurred in the Arctic since the last half century. Temperature increased 2-3 °C in some regions of the Arctic continents. Coverage of sea ice decreased 5% in the Arctic Ocean, thickness of sea ice shrunk in the center of the Arctic Ocean, the surface and intermediate water layers are freshening and warming, absorption of the atmospheric CO 2 increased in the marginal sea ice zone, and depletion of ozone appeared and ultraviolet radiation increased. To understand processes of air sea ice interaction and their impacts to global change, First Chinese National Arctic Research Expedition was conducted from July 1 to September 9 of 1999 to implement a multidisciplinary survey in the Chukchi Sea, the Canada Abyssal Plain, and the Bering Sea. Advancement has achieved to understand regional characteristics of the Arctic and the sub Arctic as well as their effective processes on global change. A phenomenon of persistent warming has been observed in the medial layer waters in the Canada Abyssal Plain where has also been found as a major sink of fresh water from rivers to the Arctic Ocean. Exchange of water masses between the western Arctic Ocean and the Bering Sea as well as warm water structure in secondary surface layers were studied. Using data from multidisciplinary investigations on a floating packed ice, the atmospheric boundary layer was characterized, variations of energy balance on the underlying surface were modeled, and as air sea and ice air turbulent fluxes were calculated respectively, as well as differences of their parameters in the boundary layer were discussed. Fluxes of air sea CO 2 showed that most of the surveyed waters would play as a sink of the atmospheric CO 2. Higher biological pump operations presented in the western Arctic Ocean with an effective organic carbon sink in the Chukchi Sea. Microbiological activities didn′t find remarkably suppressed even in the cold waters. Biological processes of iodine in the surveyed sediment cores indicated a trend of concentration distribution increases from low to high latitude, suggesting a potential sink of iodine in the Arctic region and implying iodine as a significant indicator for variations of paleooceanic geochemical elements in the polar regions. There was a diversity of community and a variety of ecological structure in the Chukchi Sea or the Bering Sea, but a higher nutrient and low chlorophyll (HNLC) appeared in the Bering Abyssal Basin and lower levels of primary production and particle organic matters occurred in summer sea ice melting season in the Chukchi Sea. Pb in marine aerosols over the Chukchi Sea showed a high concentration. Ozone concentrations in the surface air or their daily change magnitude decreased with increase of latitude, which could be attributed to impacts from climate system such as from a warm high passed or a change of the tropopause height.