Antarctic iceberg impacts on future Southern Hemisphere climate
Antarctic iceberg impacts on future Southern Hemisphere climate
复制标题
DOI：
10.1038/s41558-019-0546-1
复制
发表时间：
2019-09-01
影响因子：
30.7
通讯作者：
Pollard, David
中科院分区：
文献类型：
--
作者：
Schloesser, Fabian;Friedrich, Tobias;Pollard, David
未来南极冰盖（AIS）的冰山和融水排放量可能会大大超过目前的水平，对未来的气候和海平面产生强烈影响。最近的气候模式模拟AIS的快速解体对气候的影响，采用了理想化的淡水强迫情景（1，2），而不是更现实的冰山强迫。在这里，我们使用一个耦合的气候-冰山模型来确定冰山融合潜热和淡水强迫相结合的气候效应。冰山作用力来自于使用宾夕法尼亚州冰盖模型进行的未来模拟的集合（3）。与以前的研究一致，模拟AIS融水强迫导致南半球温室变暖的大幅延迟，并激活表面清新，地下变暖和冰盖/冰架融化之间的瞬时正反馈，这可能持续约100年，并可能导致南极洲周围的冰加速损失。然而，进一步考虑由于冰山融化引起的海洋热损失大大增加了表面冷却效应，并降低了次表层温度反馈幅度。我们的研究结果证明了考虑现实的气候-冰盖-冰山耦合对未来气候和海平面预测的重要性。
Future iceberg and meltwater discharge from the Antarctic ice sheet (AIS) could substantially exceed present levels, with strong implications for future climate and sea levels. Recent climate model simulations on the impact of a rapid disintegration of the AIS on climate have applied idealized freshwater forcing scenarios(1,2) rather than the more realistic iceberg forcing. Here we use a coupled climate-iceberg model to determine the climatic effects of combined iceberg latent heat of fusion and freshwater forcing. The iceberg forcing is derived from an ensemble of future simulations conducted using the Penn State ice-sheet model(3). In agreement with previous studies, the simulated AIS meltwater forcing causes a substantial delay in greenhouse warming in the Southern Hemisphere and activates a transient positive feedback between surface freshening, subsurface warming and ice-sheet/shelf melting, which can last for about 100 years and may contribute to an accelerated ice loss around Antarctica. However, accounting further for the oceanic heat loss due to iceberg melting considerably increases the surface cooling effect and reduces the subsurface temperature feedback amplitude. Our findings document the importance of considering realistic climate-ice sheet-iceberg coupling for future climate and sea-level projections.