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首页> 外文期刊>Climate of the past >Simulation of the Greenland Ice Sheet over two glacial–interglacial cycles: investigating a sub-ice-shelf melt parameterization and relative sea level forcing in an ice-sheet–ice-shelf model
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Simulation of the Greenland Ice Sheet over two glacial–interglacial cycles: investigating a sub-ice-shelf melt parameterization and relative sea level forcing in an ice-sheet–ice-shelf model

机译：格陵兰冰盖在两个冰期至冰期之间的模拟：在冰盖-冰架模型中研究冰盖下的融化参数和相对海平面强迫

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Observational evidence, including offshore moraines and sediment cores, confirm that at the Last Glacial Maximum (LGM) the Greenland ice sheet (GrIS) expanded to a significantly larger spatial extent than seen at present, grounding into Baffin Bay and out onto the continental shelf break. Given this larger spatial extent and its close proximity to the neighbouring Laurentide Ice Sheet (LIS) and Innuitian Ice Sheet (IIS), it is likely these ice sheets will have had a strong non-local influence on the spatial and temporal behaviour of the GrIS. Most previous paleo ice-sheet modelling simulations recreated an ice sheet that either did not extend out onto the continental shelf or utilized a simplified marine ice parameterization which did not fully include the effect of ice shelves or neglected the sensitivity of the GrIS to this non-local bedrock signal from the surrounding ice sheets. In this paper, we investigated the evolution of the GrIS over the two most recent glacial–interglacial cycles (240?ka?BP to the present day) using the ice-sheet–ice-shelf model IMAU-ICE. We investigated the solid earth influence of the LIS and IIS via an offline relative sea level (RSL) forcing generated by a glacial isostatic adjustment (GIA) model. The RSL forcing governed the spatial and temporal pattern of sub-ice-shelf melting via changes in the water depth below the ice shelves. In the ensemble of simulations, at the glacial maximums, the GrIS coalesced with the IIS to the north and expanded to the continental shelf break to the southwest but remained too restricted to the northeast. In terms of the global mean sea level contribution, at the Last Interglacial (LIG) and LGM the ice sheet added 1.46 and ?2.59?m, respectively. This LGM contribution by the GrIS is considerably higher (～ 1.26?m) than most previous studies whereas the contribution to the LIG highstand is lower (～ 0.7?m). The spatial and temporal behaviour of the northern margin was highly variable in all simulations, controlled by the sub-ice-shelf melting which was dictated by the RSL forcing and the glacial history of the IIS and LIS. In contrast, the southwestern part of the ice sheet was insensitive to these forcings, with a uniform response in all simulations controlled by the surface air temperature, derived from ice cores.
机译：包括近海的冰晶和沉积物核心在内的观察证据证实，格陵兰冰盖（GrIS）在最后冰川期（LGM）膨胀到比现在明显更大的空间范围，扎根到巴芬湾并延伸到大陆架断裂。鉴于此较大的空间范围及其与相邻的Laurentide冰盖（LIS）和Innuitian冰盖（IIS）的距离非常近，这些冰盖可能会对GrIS的时空行为产生强烈的非局部影响。以前的大多数古冰盖模拟模拟都重新创建了一个冰盖，该冰盖要么没有延伸到大陆架上，要么利用简化的海洋冰参数化，而该参数化并没有完全包括冰架的影响或忽略了GrIS对这种非冰盖的敏感性。来自周围冰原的当地基岩信号。在本文中，我们使用冰盖-冰架模型IMAU-ICE研究了两个最近的冰-冰间循环（到今天为240？ka？BP）期间GrIS的演变。我们通过冰川等静压调整（GIA）模型生成的离线相对海平面（RSL）强迫调查了LIS和IIS的固体地球影响。 RSL强迫通过冰架下方水深的变化控制了子冰架融化的时空格局。在模拟合奏中，在冰川最大时，GriS与IIS合并到北部，并扩展到西南的大陆架断裂带，但仍然局限于东北。就全球平均海平面贡献而言，在上一次冰间期（LIG）和LGM上，冰盖分别增加了1.46和？2.59？m。 GrIS对LGM的贡献比以前的大多数研究高得多（〜1.26？m），而对LIG高位的贡献则较低（〜0.7？m）。在所有模拟中，北缘的时空变化都很大，受亚冰架融化的控制，这是由RSL强迫以及IIS和LIS的冰川历史决定的。相比之下，冰原的西南部分对这些强迫不敏感，在所有模拟中，由冰芯派生的地表空气温度控制的响应都是一致的。

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