Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland, before and during a retreat.
Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland, before and during a retreat.
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DOI：
10.1073/pnas.2220924120
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发表时间：
2023-05-16
影响因子：
11.1
通讯作者：
Dini, Luigi
中科院分区：
文献类型：
--
作者：
Ciraci, Enrico;Rignot, Eric;Scheuchl, Bernd;Tolpekin, Valentyn;Wollersheim, Michael;An, Lu;Milillo, Pietro;Bueso-Bello, Jose-Luis;Rizzoli, Paola;Dini, Luigi
我们展示了格陵兰岛西北部主要的出口冰川——彼得曼冰川的接地冰与海洋边界（即接地线）处的冰川冰动力学和冰融化速率的记录。在负责预测海平面上升的冰盖模型中所采用的传统接地线观点是，它们在潮汐周期中不会迁移，且不会发生冰融化。然而，卫星记录显示，接地线会发生千米级的迁移（即接地带），并且会优先沿着先前存在的冰下通道侵入。在接地带内记录到了最高的冰融化速率。在千米宽的接地带中强烈的冰 - 海洋相互作用将使冰川导致的海平面上升预测值可能翻倍。
格陵兰岛周围海水变暖在推动冰川消退以及冰川对海平面上升的影响方面起着重要作用。然而，海洋与接地冰交界处（即接地线）的融化速率并不为人们所熟知。在此，我们利用来自德国TanDEM - X任务、意大利COSMO - SkyMed星座以及芬兰ICEYE星座的卫星雷达干涉测量数据的时间序列，来记录格陵兰岛西北部主要的海洋性冰川——彼得曼冰川的接地线迁移和底部融化速率。我们发现，接地线在千米宽（2到6千米）的接地带上以潮汐频率迁移，这比刚性基床上的接地线预期的迁移范围大一个数量级。在接地带内的冰架融化速率最高，沿着侧向受限的通道，其值在60±13到80±15米/年之间。随着2016年到2022年接地线后退了3.8千米，它侵蚀出了一个约204米高的空洞，其中融化速率从2016年到2019年的40±11米/年增加到2020年到2021年的60±15米/年。2022年，这个空洞在整个潮汐周期中都保持开放。这种集中在千米宽接地带的高融化速率与预测融化速率为零的传统接地线融化羽流模型形成了对比。数值模型中接地冰川冰的模拟底部高融化速率将增加冰川对海洋变暖的敏感性，并可能使海平面上升的预测值翻倍。
We present a record of glacier ice dynamics and ice melt rate at the boundary between grounded ice and ocean—or grounding line—of Petermann Glacier, a major outlet glacier in Northwest Greenland. The traditional view of grounding lines implemented in ice sheet models in charge of projecting sea level rise is that they not migrate during the tidal cycle and experiences no ice melt. Instead, the satellite record reveals kilometer-size grounding line migrations—or grounding zones—with preferential intrusions along preexisting subglacial channels. The highest melt rates of ice are recorded within the grounding zone. Vigorous ice-ocean interaction in kilometer-wide grounding zone will make projections of sea level rise from glaciers potentially double. Warming of the ocean waters surrounding Greenland plays a major role in driving glacier retreat and the contribution of glaciers to sea level rise. The melt rate at the junction of the ocean with grounded ice—or grounding line—is, however, not well known. Here, we employ a time series of satellite radar interferometry data from the German TanDEM-X mission, the Italian COSMO-SkyMed constellation, and the Finnish ICEYE constellation to document the grounding line migration and basal melt rates of Petermann Glacier, a major marine-based glacier of Northwest Greenland. We find that the grounding line migrates at tidal frequencies over a kilometer-wide (2 to 6 km) grounding zone, which is one order of magnitude larger than expected for grounding lines on a rigid bed. The highest ice shelf melt rates are recorded within the grounding zone with values from 60 ± 13 to 80 ± 15 m/y along laterally confined channels. As the grounding line retreated by 3.8 km in 2016 to 2022, it carved a cavity about 204 m in height where melt rates increased from 40 ± 11 m/y in 2016 to 2019 to 60 ± 15 m/y in 2020 to 2021. In 2022, the cavity remained open during the entire tidal cycle. Such high melt rates concentrated in kilometer-wide grounding zones contrast with the traditional plume model of grounding line melt which predicts zero melt. High rates of simulated basal melting in grounded glacier ice in numerical models will increase the glacier sensitivity to ocean warming and potentially double projections of sea level rise.
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影响因子：
4.6
作者：
Mohajerani Y;Jeong S;Scheuchl B;Velicogna I;Rignot E;Milillo P
通讯作者：
Milillo P
DOI：
10.1073/pnas.2015483118
发表时间：
2021-01-12
影响因子：
11.1
作者：
An L;Rignot E;Wood M;Willis JK;Mouginot J;Khan SA
通讯作者：
Khan SA
影响因子：
4.3
作者：
Golledge, Nicholas R.;Thomas, Zoe A.;Fogwill, Christopher J.
通讯作者：
Fogwill, Christopher J.
影响因子：
8.9
作者：
Hersbach, Hans;Bell, Bill;Thepaut, Jean-Noel
通讯作者：
Thepaut, Jean-Noel
影响因子：
5.2
作者：
Howat, I. M.;Negrete, A.;Smith, B. E.
通讯作者：
Smith, B. E.