The Impact of Föhn Winds on Surface Energy Balance During the 2010–2011 Melt Season Over Larsen C Ice Shelf, Antarctica
The Impact of Föhn Winds on Surface Energy Balance During the 2010–2011 Melt Season Over Larsen C Ice Shelf, Antarctica
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DOI：
10.1002/2017jd026809
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发表时间：
2017-11
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影响因子：
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通讯作者：
John C. King;A. Kirchgaessner;S. Bevan;A. Elvidge;P. K. Munneke;A. Luckman;A. Orr;I. Renfrew;M. R. Broeke
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作者：
John C. King;A. Kirchgaessner;S. Bevan;A. Elvidge;P. K. Munneke;A. Luckman;A. Orr;I. Renfrew;M. R. Broeke
我们使用模式数据从南极中尺度预报系统（AMPS），自动气象站和卫星观测的测量，调查之间的关联表面能量平衡（SEB），表面融化，并在拉森C冰架（南极半岛）在2010年11月至2011年3月期间föhn风的发生。在这段时间里，有超过20%的时间出现了焚风条件，这与冰架西部的气温升高和相对湿度降低（相对于非焚风条件）有关。在föhn条件下，向下湍流感热通量和下沉流短波辐射都增加。然而，在AMPS中，这些变暖趋势在很大程度上被上升潜热通量的增加和下降长波辐射的减少所平衡，因此风对模拟的净SEB的影响很小。这种平衡对模型中表面能通量的表示高度敏感，有限的验证数据表明AMPS可能低估了SEB和熔体对föhn的敏感性。有广泛的协议之间的模型和卫星观测融化的空间格局，但不一致的频率与融化发生。卫星观测表明，沿着南极半岛山脚的持续融化的局部地区没有模拟的模式。此外，熔体被观察到持续在这些地区在延长的时间内，当föhn不发生，这表明其他因素可能是重要的，在控制这些地区的熔体。
We use model data from the Antarctic Mesoscale Prediction System (AMPS), measurements from automatic weather stations and satellite observations to investigate the association between surface energy balance (SEB), surface melt, and the occurrence of föhn winds over Larsen C Ice Shelf (Antarctic Peninsula) over the period November 2010 to March 2011. Föhn conditions occurred for over 20% of the time during this period and are associated with increased air temperatures and decreased relative humidity (relative to nonföhn conditions) over the western part of the ice shelf. During föhn conditions, the downward turbulent flux of sensible heat and the downwelling shortwave radiation both increase. However, in AMPS, these warming tendencies are largely balanced by an increase in upward latent heat flux and a decrease in downwelling longwave radiation so the impact of föhn on the modeled net SEB is small. This balance is highly sensitive to the representation of surface energy fluxes in the model, and limited validation data suggest that AMPS may underestimate the sensitivity of SEB and melt to föhn. There is broad agreement on the spatial pattern of melt between the model and satellite observations but disagreement in the frequency with which melt occurs. Satellite observations indicate localized regions of persistent melt along the foot of the Antarctic Peninsula mountains which are not simulated by the model. Furthermore, melt is observed to persist in these regions during extended periods when föhn does not occur, suggesting that other factors may be important in controlling melt in these regions.