The Ice of the Southern Ocean

Regular sea ice observations off the coasts of Antarctica in the Mirny Station area have been made by the Soviet Antarctic Expedition since 1956. For eight years air ice reconnaissance over the Davis Sea has been made from Mirny Station during all the seasons of the year from the shore to the ice edge. During the voyages of the d/e ship O_B special observations on sea ice and icebergs have been made in the coastal zone of Antarctica. Physical properties, formation and desintegration of sea ice have been studied. The data obtained on sea ice peculiarities may be spread over a vast water area of the Southern Ocean. For many years the author has studied sea ice in the Arctic Ocean. The paper deals with general features of sea ice existence in the Antarctic and with differences. The formation and growth of ice from sea water both in the Arctic and Antarctic depend mainly upon air temperature and heat content in the sea. Disintegration and melting of ice in the Antarctic occur differently. Solar radiation, a great amount of diatoms included in the ice thickness and currents carrying ice out to the north into more warm waters play most important part here. The amount of old ice remaining in the Antarctic waters after the summer season is considerably less than in the Arctic waters. In the coastal zone of Antarctica due to ice cooling from ice cliffs, ice shelves and icebergs a great amount of intra-water ice crystals are formed. The crystals, coming to the surface, increase ice thickness. Due to great depths the width of the fast ice at the coasts of Antarctica is 20-30 miles, the width of the fast ice in the Arctic is hundreds of miles. A characteristic peculiarity of the Antarctic waters is the existence of icebergs. The icebergs have irregular spreading over the water area of the Southern Ocean. Soviet investigators have made an attempt to calculate the volume of fresh water in icebergs. It has been established that the annual runoff of fresh water from melting of icebergs is negligible and does not play any important part in the hydrological regime of the Southern Ocean. But icebergs have great influence on water temperature at coasts, on sea ice distribution and, consequently, on the conditions of the ship navigation in the Antarctic waters

Preface to special section on Beaufort Gyre Climate System Exploration Studies : documenting key parameters to understand environmental variability

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C00A08, doi:10.1029/2008JC005162.The BG Observational program has been jointly supported by the USA National Science Foundation, Division of Polar Programs (Arctic Science) since 2003 (ARC-0424864); by Fisheries and Oceans Canada; and partially by the Japan Agency for Marine-Earth Science and Technology

An ancient bison from the mouth of the Rauchua River (Chukotka, Russia)

An incomplete carcass of an extinct bison, Bison ex gr. priscus, was discovered in 2012 in the mouth of the Rauchua River (69°30'N, 166°49'E), Chukotka. The carcass included the rump with two hind limbs, ribs, and large flap of hide from the abdomen and sides, several vertebrae, bones of the forelimbs and anterior autopodia, stomach with its contents, and wool. The limb bones are relatively gracile, which is unusual in bison, and a SEM study of the hair microstructure suggests higher insulating capacity than in extant members of the genus. Additionally, mitochondrial DNA analyses indicate that the Rauchua bison belonged to a distinct and previously unidentified lineage of steppe bison. Two radiocarbon dates suggest a Holocene age for the bison: a traditional 14C date provided an estimate of 8030±70 14C yr BP (SPb-743) and an AMS radiocarbon date provided an age of 9497±92 14C yr BP (AA101271). These dates make this the youngest known bison from Chukotka. Analysis of stomach contents revealed a diet of herbaceous plants (meadow grasses and sedges) and shrubs, suggesting that the early Holocene vegetation near the mouth of the Rauchua River was similar to that of the present day: tundra-associated vegetation with undersized plants

Pathways and modification of the upper and intermediate waters of the Arctic Ocean,

The purpose of this study is to investigate the pathways and the ventilation of source water masses of the upper and intermediate waters of the Arctic Ocean. For the Arctic and subarctic domain, a coupled ice-ocean general circulation model is set up to be integrated for several decades. It is driven by a climatological seasonal cycle of monthly mean atmospheric data from 1980-89 and by restored sea surface salinities. Passive tracers are used to visualise and interpret the modelled flow and to compare it with observations.The model is able to reproduce known features of the Arctic Ocean circulation like the inflow of two branches of Atlantic origin via the Fram Strait and the Barents Sea and their subsequent passage at mid depths in several cyclonic circulation cells. The fate of these Atlantic source water masses, river water and Bering Strait inflow water in the model are studied. The branch crossing the Barents Sea is subject to an intense heat loss and ice formation. As a result water of this branch leaves the shelf towards the central part of the Arctic Ocean not only at the surface but also in denser varieties which finally feed the central Arctic at halocline and mid depths. The lightest part turns northward and finally westward joining the Transpolar Drift, the densest part (200-1000 m depth) move eastward along the continental slope. A similar path is taken by the Atlantic water branch from the Fram Strait. The inflowing branch over the Barents Sea turns out to be the dominant source for the lower Atlantic Water layer in the Arctic Ocean in this investigation.Atlantic tracers starting in Fram Strait need 6 years to reach the northern Laptev Sea slope. Travel times to return to Fram Strait are 15 - 20 years along the Lomonossov Ridge and about 30 years along the continental slope of the Canadian Basin. Tracers which mark the Pacific Water or the Mackenzie river water flow eastward and leave the Arctic mainly via the Canadian Archipelago. The Siberian river water tracers at the surface penetrate far into the Canadian Basin before they join the Transpolar Drift. The travel times of the river water from the river mouths are 2-3 years to the shelf edge and 12-14 years to Fram Strait