210pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spa- tial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin...210pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spa- tial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin. The specific activities varied from 0.04 to 2.72, 〈0.013 to 4.37, and 0.1 to 4.85 Bq/m3 for dissolved, particu- late, and bulk 210pb, respectively, corresponding to respective averages of 0.65, 0.43, and 1.08 Bq/m3. In the Canadian Basin, the minimum 210pb activities occurred in the thermocline, which was characterized by low temperature of-1.52℃ and salinity of 33.1. Combining the spatial distribution of 210pb and hydrographical characteristics in the western Arctic Ocean, this scenario was ascribed to the effective scavenging of 210pb when the Pacific water flowed across the Chukchi Shelf. Quantitatively, this interpretation was supported by both the shorter residence times and higher scavenging efficiencies （SE） of dissolved 210pb over the Chukchi Shelf. The highest SE values were observed in the Herald Shoal and bottom waters over the slope.展开更多
A combination of 5180 and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008. The Arctic river water and Pacific river water were quantitatively distinguished by using diff...A combination of 5180 and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008. The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members. The fractions of total river water, including the Arctic and Pacific river water, were high in the upper 50 m and decreased with depth as well as increasing latitude. In contrast, the fraction of Pacific river water increased gradually with depth but decreased toward north. The inventory of total river water in the Canada Basin was higher than other arctic seas, indicating that Canada Basin was a main storage region for river water in the Arctic Ocean. The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m. As a result, the inventories of Pacific river water were higher than those of Arctic river water, demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin. Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted. The fractions of total river water, Arctic river water, Pacific river water increased northward to the north of 82°N, indicating an additional source of river water in the permanent ice zone of the northern Canada Basin. A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift. The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin, while it extended to 125 m in the northern Canada Basin. The inventory of sea- ice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone, attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre.展开更多
基金The Chinese Polar Environment Comprehensive Investigation and Assessment Programs under contract No.CHINARE2014-03-04-03the National Natural Science Foundation of China under contract No.41125020+1 种基金the 4th Chinese Arctic Research Programthe Polar Science Strategic Research Foundation of China under contract No.20120307
文摘210pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spa- tial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin. The specific activities varied from 0.04 to 2.72, 〈0.013 to 4.37, and 0.1 to 4.85 Bq/m3 for dissolved, particu- late, and bulk 210pb, respectively, corresponding to respective averages of 0.65, 0.43, and 1.08 Bq/m3. In the Canadian Basin, the minimum 210pb activities occurred in the thermocline, which was characterized by low temperature of-1.52℃ and salinity of 33.1. Combining the spatial distribution of 210pb and hydrographical characteristics in the western Arctic Ocean, this scenario was ascribed to the effective scavenging of 210pb when the Pacific water flowed across the Chukchi Shelf. Quantitatively, this interpretation was supported by both the shorter residence times and higher scavenging efficiencies （SE） of dissolved 210pb over the Chukchi Shelf. The highest SE values were observed in the Herald Shoal and bottom waters over the slope.
基金The Chinese Polar Environment Comprehensive Investigation&Assessment Program under contract Nos CHINARE2017-03-04-03 and CHINARE2017-04-03-05the Natural Science Foundation of China under contract No.41125020
文摘A combination of 5180 and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008. The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members. The fractions of total river water, including the Arctic and Pacific river water, were high in the upper 50 m and decreased with depth as well as increasing latitude. In contrast, the fraction of Pacific river water increased gradually with depth but decreased toward north. The inventory of total river water in the Canada Basin was higher than other arctic seas, indicating that Canada Basin was a main storage region for river water in the Arctic Ocean. The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m. As a result, the inventories of Pacific river water were higher than those of Arctic river water, demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin. Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted. The fractions of total river water, Arctic river water, Pacific river water increased northward to the north of 82°N, indicating an additional source of river water in the permanent ice zone of the northern Canada Basin. A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift. The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin, while it extended to 125 m in the northern Canada Basin. The inventory of sea- ice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone, attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre.
