HR: 0800h
AN: OS41A-0458    [Abstracts]
TI: Horizontal and vertical distribution of freshwater in the Arctic Ocean deduced from historical hydrochemistry
AU: * Kawai, M Y
EM: yamami@iarc.uaf.edu
AF: International Arctic Research Center/University of Alaska Fairbanks, 930 Koyukuk Drive, Fairbanks, AK 99775-7335 United States
AU: Tanaka, N
EM: norit@iarc.uaf.edu
AF: International Arctic Research Center/University of Alaska Fairbanks, 930 Koyukuk Drive, Fairbanks, AK 99775-7335 United States
AU: Pivovarov, S
EM: pivovarov@mail.lanck.net
AF: Arctic and Antarctic Research Institute, 38 Bering Street, St. Petersburg, 199397 Russian Federation
AU: Timokhov, L
EM: ltim@aari.nw.ru
AF: Arctic and Antarctic Research Institute, 38 Bering Street, St. Petersburg, 199397 Russian Federation
AB: Historical data (1935-2002) of two chemical tracers, oxygen isotope ratio and alkalinity, are combined and freshwater sources of sea ice meltwater (SIM), and other freshwater (OF) are distinguished from each pair of two conservative elements, salinity-oxygen isotope and salinity-alkalinity. The OF consists of mainly river runoff, with addition of precipitation and salinity deficit of inflowing Pacific water. Results give at first startling pictures of both horizontal and vertical distributions of freshwaters from the two designated sources almost throughout the Arctic Ocean. River water sources in Canada Basin: Distribution of OF at the 10 depth shows that river water from the Russian shelf seas flows out of the shelf between the Mendeleyev and the Lomonosov Ridges and exits thorough western part of the Fram Strait. Part of this freshwater enters into the Canadian Basin, where water contains large amount of OF but small fraction of American river water. This may suggest that river water from American continent should exit from the basin relatively fast though the Canadian Archipelago. Vertical mixing of fresh water: The atmospheric cooling and brine rejection during winter converts fresh surface water into denser water with high OF and negative SIM signals. High inventories of both OF and negative SIM, which implies mixing with brine, are found in the Canadian Basin, Baffin Bay and east of Novaya Zemlya in the Kara Sea. These signals in the Kara Sea and the Baffin Bay show occurrence of deep convection in winter, whereas those in the Canadian Basin come from adjacent shallow shelves. In the Canadian Basin, negative SIM distribution is well corresponding to the low temperature layer between surface and Atlantic origin waters. This layer characterized by nutrient maximum with a salinity of about 33.1 and is found to form from the water having salinity of 31-32. Our analysis advocates the importance of shelf water from the East Siberian Sea on formation of water mass in this layer. The shelf water vertically transports both OF and brine from the surface to the deeper layer and accumulates in the Canadian Basin. We appreciate Drs. Murata and Shimada of JAMSTEC for providing unpublished data from the past Arctic expeditions by R/V Mirai.
DE: 4808 Chemical tracers
DE: 4207 Arctic and Antarctic oceanography
DE: 4215 Climate and interannual variability (3309)
DE: 4283 Water masses
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting