英国爱丁堡大学Miles, Bertie W. J.小组的最新研究提出了自1973年以来南极冰架的逐步解锚这一新看法。相关论文发表在2024年2月21日出版的《自然》杂志上。

研究人员测量了1973-1989年、1989-2000年和2000-2022年三个时期的钉点变化。并由此推断出1973-1989年冰该厚度的变化。研究发现，在1973-1989年期间，只有一小部分局部冰盖变薄，主要位于Amundsen海湾和Wilkes陆地海岸线。冰盖减薄在20世纪90年代和21世纪初迅速蔓延，其最显著特征是钉点的比例在一定程度上减少。从1973-1989年，只有15%的钉点下降，然后从1989-2000年增加到25%，从2000-2022年增加到37%。如果这一趋势继续下去，将进一步减少冰架的支撑潜力，增加冰的流量，并加速南极洲对海平面上升的贡献。

据悉，南极冰盖的质量损失主要是由冰盖边缘的浮冰架变薄造成的，浮冰架的支撑能力降低，导致陆地冰加速流入海洋。卫星测高法对冰盖厚度变化的观测只能追溯到1992年，之前关于变薄的信息仍未量化。然而，通过测量锚定点(冰盖所锚定的局部测深高点)表面表现的面积变化，可以用替代方法扩展冰架厚度变化的记录。

附：英文原文

Title: Progressive unanchoring of Antarctic ice shelves since 1973

Author: Miles, Bertie W. J., Bingham, Robert G.

Issue&Volume: 2024-02-21

Abstract: Mass loss of the Antarctic Ice Sheet has been driven primarily by the thinning of the floating ice shelves that fringe the ice sheet, reducing their buttressing potential and causing land ice to accelerate into the ocean. Observations of ice-shelf thickness change by satellite altimetry stretch back only to 1992 and previous information about thinning remains unquantified. However, extending the record of ice-shelf thickness change is possible by proxy, by measuring the change in area of the surface expression of pinning points—local bathymetric highs on which ice shelves are anchored. Here we measure pinning-point change over three epochs spanning the periods 1973–1989, 1989–2000 and 20002022, and thus by proxy infer changes to ice-shelf thickness back to 1973–1989. We show that only small localized pockets of ice shelves were thinning between 1973 and 1989, located primarily in the Amundsen Sea Embayment and the Wilkes Land coastline. Ice-shelf thinning spreads rapidly into the 1990s and 2000s and is best characterized by the proportion of pinning points reducing in extent. Only 15% of pinning points reduced from 1973 to 1989, before increasing to 25% from 1989 to 2000 and 37% from 2000 to 2022. A continuation of this trend would further reduce the buttressing potential of ice shelves, enhancing ice discharge and accelerating the contribution of Antarctica to sea-level rise.

DOI: 10.1038/s41586-024-07049-0

Source: https://www.nature.com/articles/s41586-024-07049-0