| As the world’s cold source, the arctic plays an important role in regulating the global climate system.The climate of arctic is undergoing rapid change during the past 30 years, which affects the environment and climate of global especially the northern hemisphere. The Chinese arctic expedition has completed 4 voyage of arctic investigates since the first implementation of the arctic expedition in 1999. So a large number of valuable research data has been accessed. The Bering Sea and Chukchi Sea as important areas in the arctic research, has a quite important role in the process of the earth’s climate system evolution. The emphasis of this paper is to study the summer interannual variability hydrological structure of Bering Sea and Chukchi Sea, and the following problems has been solved:First of all,based on the conductivity-temperature-depths（CTD） data obtained within the Bering Sea by Chinese National Arctic Research Expedition during 2008, 2010, 2012 and 2014, the water mass, upper ocean heat content, the net heat flux change, wind field and the sea level pressure were analyzed to discusses the inter-annual variability of the hydrological structure characteristics in Bering Sea. It is found that（1） the waters of Bering Sea can be divided into four masses: Bering Upper Water（BUW）, Bering Middle Water（BIW）, Bering Deep Water（BDW） and Bering Shelf Water（BSW）.（2） The variations of temperature and salinity mainly concentrated in the upper water.（3） In July 2012, the upper water temperature bellows normal level, while in July 2014, strongly positive temperature anomalies developed in the upper water and the Bering Winter Water appeared 50-70 m shallower than any other years.（4）The abnormal phenomenon showed in terms of lower heat content in July 2012 and higher heat content in July 2014 respectly.Second,the the characteristics of weather such as net heat flux, wind field and sea slevel pressure of Bering Sea has been analyzed using the historical sharing data to focus on studying the reasons of higher SST anomaly in July 2014. The results indicate that（1） Whole of the Bering Sea is getting heat during summer. The net heat flux of most areas is between 160 W·m-2 to 240 W·m-2.（2） The mechanism of SST anomaly in July 2014 is totally different from basin to shelf. The higher SST apperred in shelf is mainly because of the higher cumulative net heat flux from May to July in the area, the water absorbed amount of energy so that the SST rises.（3） But in basin, it is due to the unusually strong and lasting high pressure system combined with negative wind stress crul. From May to July 2014, the unusually strong sea level pressure caused the west stations dominated by southern winds continuously on one hand. On the other hand, the negative wind stress curl enhanced, so that to strengthen the anti-cyclonic circulation of Bering Sea upper ocean. The BWW warmed by Ekman pumping coupling which make surface water sink into the subsurface.Third, the thermohaline distribution and interannual variability of C, R and SR sections of Chukchi have been analyzed based on the Arctic scienticfic expedition in the year 2008, 2010, 2012 and 2014. The results showed that（1） The most prominent feature of the section C is that, the west side featured as low temperature but high salinity, while the east side featured as high temperature but low salinity. There is a significant thermohaline front at the most south of C1 sections near 167.5°W. The C2 section is remarkable stratificated with temperature lower than C1 section. On the west side of the section there is cold water with temperature below 0℃. On the C3 section north to C2, the thermohaline stratified significant.At the bottom there is high salt water with temperature below-1℃.（2） The observation time of R section is about a month earlier than the SR section, so the thermhaline variable. It is found that the temperature observed in the SR section is about 1 ℃ higher than the R section. The salinity varies remarkable than temperature. The return observastion data shows that the light salt water has been diffused to the deep ocean from surface. The salinity of deep water declined about 1.5psu as a whole.Fourth, the interannual variability of surface thermoline and water mass of Chukchi Sea were discussed using the data from Arctic expedition during 2008 to 2014. The results include（1） The Chukchi sea surface temperature decreases gradually from south to north. Temperature in Hope Point of Alaska is 1 to 2℃ higher than the central, while the salinity is lower than the vicinity.（2） The water mass of Chukchi Sea in summer include the Alaska Coastal Water（ACW）, the Pacific Winter Water（PWW）, the Season Melt Water（SMW）, the Atalntic Water（AW） and the Chukchi Summer Water（CSW）. Among them, this paper subdivided the PWW into the Newly-ventilated Pacific Winter Water（NPWW） and the Remnant Pacific Winter Water（RPWW） by-1.6℃. The SMW is been subdivided into the Early Season Melt Water（ESMW） and the Late Season Melt Water（LSMW） by-1℃.（3） The thermohaline of Chukchi Sea surface water changes appearently. Salinity of the Chukchi surface water decreases gradually during the transporation of the Pacific to the north been influenced by ice melting. The ACW interact with the CSW as a result of the ACW been expanded. The range of PWW is maximum in 2012, while not be observed during the survey in 2014. |
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