Reconstructing Greenland ice sheet runoff using coralline algae
Reconstructing Greenland ice sheet runoff using coralline algae
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DOI：
10.1130/g33405.1
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发表时间：
2012-12-01
期刊：
影响因子：
5.8
通讯作者：
Claverie, Thomas
中科院分区：
文献类型：
--
作者：
Kamenos, Nicholas A.;Hoey, Trevor B.;Claverie, Thomas
格陵兰冰盖（GrIS）拥有北半球最大的淡水储存量，相当于海平面上升7.4米，但它对当前、过去和未来海平面、海洋环流和欧洲气候的影响尚不清楚。以前对GrIS融化的估计是基于26年的卫星观测和48年的温度驱动融化模型得出的，表明融化有增加的趋势。然而，没有可比持续时间的径流数据来验证融化的空间范围与径流或基于温度的径流模型之间的关系。此外，需要更长的径流记录来将格陵兰岛的融化模式扩展到百年时间尺度，从而使最近的观测和趋势能够纳入更好的历史背景。通过提取红珊瑚藻年生长带的相对盐度变化信息，开发了一种新的GrIS径流代理。我们观察到历史径流、相对盐度和海洋夏季温度在格陵兰岛桑德雷斯特罗姆峡湾之间存在显著的负相关。我们首次对GrIS河段的径流进行了重建，该河段几十年来（1939-2002年）流入桑德雷·斯特罗姆峡湾，并记录了自20世纪80年代中期以来重建径流增加的趋势。原位夏季海洋温度也遵循相同的趋势。我们认为，自公元1939年以来，大气温度在强迫径流方面发挥了重要作用。这些结果表明，我们的技术具有巨大的潜力，可以增强对大型冰盖径流的理解，因为它可以在百年到千年的时间尺度上进行融化重建。
The Greenland ice sheet (GrIS) contains the largest store of fresh water in the Northern Hemisphere, equivalent to similar to 7.4 m of eustatic sea-level rise, but its impacts on current, past, and future sea level, ocean circulation, and European climate are poorly understood. Previous estimates of GrIS melt, from 26 yr of satellite observations and temperature-driven melt models over 48 yr, show increasing melt trends. There are, however, no runoff data of comparable duration with which to validate the relationship between the spatial extent of melting and runoff or temperature-based runoff models. Further, longer runoff records are needed to extend the melt pattern of Greenland to centennial timescales, enabling recent observations and trends to be put into a better historical context. We have developed a new GrIS runoff proxy by extracting information on relative salinity changes from annual growth bands of red coralline algae. We observed significant negative relationships between historic runoff, relative salinity, and marine summer temperature in Sondre Stromfjord, Greenland. We produce the first reconstruction of runoff from a section of the GrIS that discharges into Sondre Stromfjord over several decades (1939-2002) and record a trend of increasing reconstructed runoff since the mid 1980s. In situ summer marine temperatures followed an equivalent trend. We suggest that since A. D. 1939, atmospheric temperatures have been important in forcing runoff. These results show that our technique has significant potential to enhance understanding of runoff from large ice sheets as it will enable melt reconstruction over centennial to millennial timescales.