中文摘要：

通过对2003-2012年间白令海峡64.3°N断面海水氧同位素组成的分析,应用海水δ18 O值和盐度的质量平衡关系区分出淡水中河水和海冰融化水组分的贡献,探讨白令海峡淡水组成的分布特征及其年际变化。研究表明,断面东侧阿拉斯加沿岸水影响区呈现低δ18 O值、低盐、高温、高河水组分的特征,西侧阿拉德尔水具有高δ18 O值、高盐、低海冰融化水的特征,中部白令陆架水的δ18 O值、盐度和淡水组成则居于上述二者之间。阿拉斯加沿岸水影响区河水组分的份额约为阿拉德尔水和白令陆架水的2倍,并呈现出2010年〉2012年〉2003年〉2008年的时间变化规律,受控于育空河入海径流量的时间变化。白令陆架水和阿拉斯加沿岸水影响区的海冰融化水份额较为接近,均比阿拉德尔水影响区的海冰融化水份额高约45%。海冰融化水的年际变化表现出2003年〉2008年≈2012年〉2010年的规律,受控于白令海海冰的年际变动。从断面淡水构成看,通过白令海峡的淡水平均由46%的河水和54%的海冰融化水构成,且阿拉德尔水、白令陆架水和阿拉斯加沿岸水影响区河水组分与海冰融化水组分的比值自2003年至2012年间呈增加趋势,证明太平洋入流中淡水构成的变化对北冰洋海冰的融化也起着一定的作用。

英文摘要：

Seawater δ18O at a transect along 64.3°N near Bering strait from 2003 to 2012 was determined,and the fractions of sea-ice melted water （SIM） and river water （RW） were calculated using mass balance of salinity and 3TM O. The spatial distribution and interannual variability of freshwater components in the Bering Strait were discussed. Our results showed that the signals of depleted 3TMO, low salinity, warmer temperatures and higher river runoff fractions were found in the region affected by the Alaska Coastal Water （ACW） on the eastern part of the section, while high 3TM O, high salinity, and lower sea-ice melted water fractions were observed in the western part with the influence of Anadyr water. The moderate properties were revealed in the middle part of the section with the influence of the Bering Shelf Water. The fractions of river runoff in the region affected by the Alaska Coastal Water were approximately twice as much as in regions affected by the Bering Shelf Water and the Anadyr Water. The interannual variation of river runoff fractions in regions affected by the Alaska Coastal Water showed a charac- teristic of 2010）2012）2003）2008, which was regulated by the interannual variation of the Yukon River discharge. The fractions of sea-ice melted water were similar in the regions affected by the Bering Shelf Water and the Alaska Coastal Water,and higher （-- 45 %） than those in the region affected by the Anadyr Water. The interannual variation of sea-ice melted water fractions showed a characteristic of 2003〉2008--2012〉2010,controlled by the interannual variation of sea ice cover in the Bering Sea. The freshwater pass through the Bering Strait was constitute of 46% river water and 54% sea-ice melted water in average. The fraction ratios of river water to sea-ice mel- ted water in the regions affected by the Alaskan Coastal Water, the Bering Shelf Water, and the Anadyr Water increased during 2003 to 2012,indicating that the freshwater components in the Pacific inflow also play a role i