Quantifying the potential future contribution to global mean sea level from the Filchner-Ronne basin, Antarctica
Quantifying the potential future contribution to global mean sea level from the Filchner-Ronne basin, Antarctica
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DOI：
10.5194/tc-15-4675-2021
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发表时间：
2021-10-06
期刊：
影响因子：
5.2
通讯作者：
Collins, Matthew
中科院分区：
文献类型：
--
作者：
Hill, Emily A.;Rosier, Sebastian H. R.;Collins, Matthew
南极冰盖对气候变暖的未来响应是全球平均海平面（Delta GMSL）未来变化估计的最大不确定性来源之一。质量损失目前集中在温暖的环极深水区域，但目前还不清楚目前被相对寒冷的海洋沃茨包围的冰架将如何应对未来的气候变化。研究表明，温暖的水可以冲洗Filchner-Ronne（FR）冰架腔在世纪，但内陆冰盖的反应，冰架融化率急剧增加知之甚少。在这里，我们使用冰流模型和不确定性量化的方法来项目的GMSL贡献的FR盆地RCP排放情景下，我们评估模型参数（有关冰动力学和大气/海洋强迫）对这些预测的前向传播和比例的贡献的不确定性。我们的概率预测，来自一个广泛的样本的参数空间使用代理模型，揭示了FR盆地是不太可能作出积极贡献的海平面上升到23世纪。这主要是由于随着变暖而增加的积累的缓解作用，这能够抑制与海洋驱动的大陆架下融化增加有关的冰损失。FR盆地的质量增加（负三角洲GMSL）随着变暖而增加，但这些预测的不确定性也变得更大。在最高排放情景RCP8.5中，Delta GMSL的范围可能为-103至26 mm，这种大的范围主要归因于驱动降水增加（30%）和大陆架下融化（44%）的参数的不确定性。在我们的输入参数空间的范围内，有可能出现供给FR冰架的冰流的大崩溃和退缩，以及对GMSL的实质性积极贡献（高达约100%）。300毫米），但我们认为这种情况是非常不可能的。在今后的研究中采用不确定性量化技术将有助于对潜在的海平面上升提供可靠的估计，并进一步确定限制预测的目标区域。
The future of the Antarctic Ice Sheet in response to climate warming is one of the largest sources of uncertainty in estimates of future changes in global mean sea level (Delta GMSL). Mass loss is currently concentrated in regions of warm circumpolar deep water, but it is unclear how ice shelves currently surrounded by relatively cold ocean waters will respond to climatic changes in the future. Studies suggest that warm water could flush the Filchner-Ronne (FR) ice shelf cavity during the 21st century, but the inland ice sheet response to a drastic increase in ice shelf melt rates is poorly known. Here, we use an ice flow model and uncertainty quantification approach to project the GMSL contribution of the FR basin under RCP emissions scenarios, and we assess the forward propagation and proportional contribution of uncertainties in model parameters (related to ice dynamics and atmospheric/oceanic forcing) on these projections. Our probabilistic projections, derived from an extensive sample of the parameter space using a surrogate model, reveal that the FR basin is unlikely to contribute positively to sea level rise by the 23rd century. This is primarily due to the mitigating effect of increased accumulation with warming, which is capable of suppressing ice loss associated with ocean-driven increases in sub-shelf melt. Mass gain (negative Delta GMSL) from the FR basin increases with warming, but uncertainties in these projections also become larger. In the highest emission scenario RCP8.5, Delta GMSL is likely to range from -103 to 26 mm, and this large spread can be apportioned predominantly to uncertainties in parameters driving increases in precipitation (30 %) and sub-shelf melting (44 %). There is potential, within the bounds of our input parameter space, for major collapse and retreat of ice streams feeding the FR ice shelf, and a substantial positive contribution to GMSL (up to approx. 300 mm), but we consider such a scenario to be very unlikely. Adopting uncertainty quantification techniques in future studies will help to provide robust estimates of potential sea level rise and further identify target areas for constraining projections.