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引用次数: 1
摘要
在任何时候,南大洋上都漂浮着13万座冰山;其中97%的冰山太小,无法在目前的卫星数据库中登记,然而这些小冰山的融化为南大洋提供了一个主要的输入。我们利用SCAR国际冰山数据库对南大西洋53000座冰山进行的一组独特的视觉尺寸观测,得出冰山的平均溶解速率。崩裂成两段是板状冰山的主要溶解过程,长度<4 km的冰山平均半衰期为30天,长度较大的冰山平均半衰期为60天。完全破碎产生许多长度小于1公里的冰山是罕见的。0.23 m d - 1的侧磨率加上6 km d - 1的漂移速度,或者两者的任何比例变化都符合观测到的冰山分布变化。从南极半岛到格林威治子午线,向南大洋注入的最大淡水和冰山运输的物质约2.3 × 10 26平方公里。冰山对盐度和温度的贡献,在威德尔海以北的贡献最大,在一些地区与追踪大型冰山所显示的不同。
Quantifying dissolution rates of Antarctic icebergs in open water
At any one time 130 000 icebergs are afloat in the Southern Ocean; 97% of these are too small to be registered in current satellite-based databases, yet the melting of these small icebergs provides a major input to the Southern Ocean. We use a unique set of visual size observations of 53 000 icebergs in the South Atlantic Ocean, the SCAR International Iceberg Database, to derive average iceberg dissolution rates. Fracture into two parts is the dominant dissolution process for tabular icebergs, with an average half-life of 30 days for icebergs <4 km length and 60 days for larger icebergs. Complete shatter producing many icebergs <1 km length is rare. A side attrition rate of 0.23 m d−1 combined with drift speed of 6 km d−1, or any proportional change in both numbers fits the observed changes in iceberg distribution. The largest injection into the Southern Ocean of fresh water and any iceberg-transported material takes place in a ~2.3 × 10⁶ km2 zone extending east-northeast from the Antarctic Peninsula to the Greenwich meridian. The iceberg contribution to salinities and temperatures, with maximum contribution north of the Weddell Sea, differs in some regions, from those indicated by tracking large icebergs.
期刊介绍:
Annals of Glaciology publishes original scientific articles and letters in selected aspects of glaciology-the study of ice. Each issue of the Annals is thematic, focussing on a specific subject. The Council of the International Glaciological Society welcomes proposals for thematic issues from the glaciological community. Once a theme is approved, the Council appoints an Associate Chief Editor and a team of Scientific Editors to handle the submission, peer review and publication of papers.