Evolution of a coupled marine ice sheet–sea level model
Evolution of a coupled marine ice sheet–sea level model
复制标题
海洋冰盖-海平面耦合模型的演化
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Clark
中科院分区：
文献类型：
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作者：
N. Gomez;D. Pollard;J. Mitrovica;P. Huybers;P. Clark
我们调查的海洋冰盖的稳定性耦合重力自洽海平面模型有效的自引力，粘弹性变形地球的1-D海洋冰盖架模型。的耦合模型的演变探索了一套模拟，在其中我们改变了床坡度和迫使开始撤退。我们发现，海平面下降的接地线与撤退冰盖的行为，以减缓撤退;在模拟浅反向床坡度和/或小的外部强迫，海平面的下降可以足以阻止撤退。由于冰盖几何形状的持续变化，接地线处的海平面变化率具有弹性分量，并且由于过去的冰和海洋载荷变化而具有粘性分量。当冰盖模式被迫从稳定状态，在短时间尺度（<10500年），粘性效应可以忽略不计，在给定的时间接地线迁移将取决于当地基岩地形和同期海平面变化的持续冰盖质量通量驱动。在较长的时间尺度上，对海洋冰盖目前稳定性的准确评估需要了解其过去的演变。
We investigate the stability of marine ice sheets by coupling a gravitationally self-consistent sea level model valid for a self-gravitating, viscoelastically deforming Earth to a 1-D marine ice sheet-shelf model. The evolution of the coupled model is explored for a suite of simulations in which we vary the bed slope and the forcing that initiates retreat. We find that the sea level fall at the grounding line associated with a retreating ice sheet acts to slow the retreat; in simulations with shallow reversed bed slopes and/or small external forcing, the drop in sea level can be sufficient to halt the retreat. The rate of sea level change at the grounding line has an elastic component due to ongoing changes in ice sheet geometry, and a viscous component due to past ice and ocean load changes. When the ice sheet model is forced from steady state, on short timescales (<∼500 years), viscous effects may be ignored and grounding-line migration at a given time will depend on the local bedrock topography and on contemporaneous sea level changes driven by ongoing ice sheet mass flux. On longer timescales, an accurate assessment of the present stability of a marine ice sheet requires knowledge of its past evolution.