Collaborative Research: Decoding & Predicting Antarctic Surface Melt Dynamics with Observations, Regional Atmospheric Modeling and GCMs

The presence of ice ponds from surface melting of glacial ice can be a significant threshold in assessing the stability of ice sheets, and their overall response to a warming climate. Snow melt has a much reduced albedo, leading to additional seasonal melting from warming insolation. Water run-off not only contributes to the mass loss of ice sheets directly, but meltwater reaching the glacial ice bed may lubricate faster flow of ice sheets towards the ocean. Surficial meltwater may also reach the grounding lines of glacial ice through the wedging open of existing crevasses. The occurrence and amount of meltwater refreeze has even been suggested as a paleo proxy of near-surface atmospheric temperature regimes.
Using contemporary remote sensing (microwave) satellite assessment of surface melt occurrence and extent, the predictive skill of regional meteorological models and reanalyses (e.g. WRF, ERA-Interim) to describe the synoptic conditions favourable to surficial melt is to be investigated. Statistical approaches and pattern recognition techniques are argued to provide a context for projecting future ice sheet change.
The previous Intergovernmental Panel on Climate Change (IPCC AR4) commented on our lack of understanding of ice-sheet mass balance processes in polar regions and the potential for sea-level change. The IPPC suggested that the forthcoming AR5 efforts highlight regional cryosphere modeling efforts, such as is proposed here.

冰川表层融化形成的冰塘（ice ponds），是评估冰盖稳定性及其对气候变暖整体响应的关键阈值指标。积雪融化后的反照率（albedo）会大幅降低，进而因入射太阳辐射增强而加剧季节性融化。融水径流不仅会直接造成冰盖质量损失，抵达冰川冰床的融水还可起到润滑作用，加速冰盖向海洋的流动。表层融水还可通过拓宽现有冰裂隙（crevasses）抵达冰川冰的接地线（grounding lines）。融水的重冻现象及其发生量，甚至被提议作为近地表大气温度状态的古气候代用指标（paleo proxy）。

本研究将采用现代遥感（remote sensing，微波）卫星手段，对表层融水的发生情况与覆盖范围进行评估，借此探究区域气象模式与再分析资料（如WRF、ERA-Interim）在刻画利于表层融水形成的天气尺度条件时的预测性能。统计方法与模式识别技术（pattern recognition techniques）被认为可为未来冰盖变化的预估提供支撑框架。

此前的政府间气候变化专门委员会第四次评估报告（IPCC AR4）曾指出，我们对极地地区冰盖质量平衡过程以及海平面变化潜在影响的认知仍存在不足。该委员会还提出，即将开展的第五次评估报告（AR5）应重点关注区域冰冻圈（cryosphere）建模研究，正如本研究所提出的研究方向。