Summertime cloud phase strongly influences surface melting on the Larsen C ice shelf, Antarctica
Summertime cloud phase strongly influences surface melting on the Larsen C ice shelf, Antarctica
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DOI：
10.1002/qj.3753
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发表时间：
2020-02
影响因子：
8.9
通讯作者：
E. Gilbert;Andrew Orr;John C. King;I. Renfrew;T. Lachlan-Cope;P. Field;I. Boutle
中科院分区：
文献类型：
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作者：
E. Gilbert;Andrew Orr;John C. King;I. Renfrew;T. Lachlan-Cope;P. Field;I. Boutle
南极半岛冰架的表面融化会影响冰架的物质平衡，从而影响海平面的上升。我们表明，南极半岛Larsen C冰架上的夏季云相强烈影响地表接收的辐射量，并可以决定是否发生融化。虽然以前的工作分别评估了Larsen C夏季的云相和地表能量平衡（SEB），但以前的研究没有定量地检查这种关系。此外，区域气候模式经常产生与云冰和液态水含量有关的地表辐射偏差。本研究使用英国气象局统一模式（MetUM）的高分辨率区域配置来评估云冰和液体特性对拉森C冰架上SEB的影响，以及由此导致的融化。一个案例研究的结果表明，模拟产生的垂直云相结构与飞机观测结果更相似，地表辐射偏差较小。改进了云相模拟的MetUM配置最接近地再现了观测到的表面熔化。在为期五周的夏季条件模拟中，模型熔体偏差减少到<2 W·m - 2：与先前使用默认MetUM设置的研究相比，提高了四倍。这证明了云相在决定Larsen C上夏季融化速率方面的重要性。
Surface melting on Antarctic Peninsula ice shelves can influence ice shelf mass balance, and consequently sea level rise. We show that summertime cloud phase on the Larsen C ice shelf on the Antarctic Peninsula strongly influences the amount of radiation received at the surface and can determine whether or not melting occurs. While previous work has separately evaluated cloud phase and the surface energy balance (SEB) during summertime over Larsen C, no previous studies have examined this relationship quantitatively. Furthermore, regional climate models frequently produce surface radiation biases related to cloud ice and liquid water content. This study uses a high‐resolution regional configuration of the UK Met Office Unified Model (MetUM) to assess the influence of cloud ice and liquid properties on the SEB, and consequently melting, over the Larsen C ice shelf. Results from a case‐study show that simulations producing a vertical cloud phase structure more comparable to aircraft observations exhibit smaller surface radiative biases. A configuration of the MetUM adapted to improve the simulation of cloud phase reproduces the observed surface melt most closely. During a five‐week simulation of summertime conditions, model melt biases are reduced to <2 W·m−2: a four‐fold improvement on a previous study that used default MetUM settings. This demonstrates the importance of cloud phase in determining summertime melt rates on Larsen C.