Time-trends in the pattern of ocean-atmosphere exchange in an ice core from the Weddell Sea sector of Antarctica
Time-trends in the pattern of ocean-atmosphere exchange in an ice core from the Weddell Sea sector of Antarctica
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南极洲威德尔海区冰芯海洋-大气交换模式的时间趋势
DOI：
10.3402/tellusb.v44i4.15468
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发表时间：
1992
期刊：
影响因子：
2.3
通讯作者：
R. Mulvaney
中科院分区：
文献类型：
--
作者：
D. Peel;R. Mulvaney
南极半岛东海岸受到横穿威德尔海地区的气团的强烈影响。在杜尔曼岛(70°35.2‘S，60°55.5’W)冰芯上连续记录了1795年以来降雪中δ18O、δD、Cl-和非海盐SO42-的年平均值。沿冰芯的化学变化似乎与边缘冰区冰盖密度的变化有关。自1956年以来，这些变化似乎与大气环流有关，以边缘冰区的大气压力梯度为指标。200年序列中最大的异常发生在1820-1880年期间，也就是小冰期的最后阶段。异常高的氯离子浓度、低浓度的生物衍生硫酸盐和高的重氢过剩表明，此时有一个致密、致密的边缘冰带，气旋比正常情况下更频繁地穿过冰缘以北的海洋区域。在过去的一个世纪里，超过约4‰的重氢显著减少，这意味着来自较低温度的水汽来源的降水的贡献逐渐增加，可能来自边缘冰带。这意味着，在过去的一个世纪里，该地区的冰盖可能已经显著减弱，尽管卫星证据显示，至少自1973年以来，冰缘的位置没有显著变化。DOI：10.1034/j.1600-0889.1992.00018.x
The east coast of the Antarctic Peninsula is strongly influenced by air masses that have traversed the Weddell Sea zone. A continuous record of annual-average values for δ 18 O, δD, Cl - and non sea-salt SO 4 2- in snowfall deposited since 1795, has been obtained on an ice core drilled on Dolleman Island (70°35.2′S, 60°55.5′W). Chemical changes along the ice core seem to be linked to changes in the concentration of the ice cover in the marginal ice zone. In the period since 1956, these variations appear to be coupled to the atmospheric circulation, as indexed by the atmospheric pressure gradient across the marginal ice zone. The largest anomaly in the 200-year sequence occurs in the period 1820-1880, during the final stages of the Little Ice Age. Exceptionally high concentrations of Cl - , low concentrations of biologically-derived sulphate, and high deuterium excess suggest that at this time there was a dense, compacted marginal ice zone with cyclones tracking more frequently than normal across ocean areas to the north of the ice edge. During the past century, there has been a marked decrease in deuterium excess of about 4‰, which implies that there has been a progressively increasing contribution to precipitation from moisture sources at lower temperature, probably from within the marginal ice zone. The implication is that there may have been significant weakening of the ice cover in this zone during the past century, despite satellite evidence which reveals no significant change in the position of the ice edge, at least since 1973. DOI: 10.1034/j.1600-0889.1992.00018.x