Orographic Flows and the Climate of the Antarctic Peninsula (OFCAP)

南极半岛目前是地球上变暖最快的地区之一。由于气候变暖，环境发生了巨大变化，最明显的是半岛边缘的一些漂浮冰架的后退和迅速解体。在失去冰架之后，半岛冰盖的冰川加速排干，导致全球海平面上升。推动区域快速变暖的因素尚未完全清楚，但对该地区有限的气候数据的分析表明，半岛东侧夏季快速变暖与盛行的西风强度增加之间存在联系。可以肯定的是，西风带的增强已被归因于与人为强迫有关的大气环流变化，特别是平流层臭氧的消耗和温室气体的增加。因此，很有可能是人为强迫导致了半岛的迅速变暖。我们提出了一个实地观测、分析和建模的综合方案，旨在了解西风如何与南极半岛的山脉相互作用，以及这些相互作用如何控制半岛东侧的气候。我们的实地观察将集中在为期一个月(2011年1月)的密集实地活动中。在此期间，将使用一架仪表式飞机和沿线的四个自动气象站观测南纬67度左右穿过南极半岛山脉的样带上的大气流动。将使用气球携带的无线电探空仪测量山脉上风(西部)和下风(东部)两侧的大气状况，同时将在半岛东部拉森冰架上的一个营地监测推动表面融化的能量通量(太阳和地面辐射、湍流热通量)。为了更全面地了解横跨半岛的气流，我们将结合高分辨率大气模式模拟的结果来使用这些观测结果。观测和模拟结果将为该地区大气流动、地形和地表气候之间的联系提供新的见解。在建立了这些联系之后，我们将利用我们对区域气候控制的新理解，利用政府间气候变化专门委员会第四次评估报告中对大范围大气流动变化的预测，为该区域制定合理的未来(未来100年)气候情景。我们的工作成果将对研究南极半岛环境变化及其更广泛影响的许多科学家小组有价值，包括冰川学家、海洋学家以及海洋和陆地生物学家。该提案还将有助于提高山区数值天气预报和气候模式的总体性能。

The Antarctic Peninsula is currently one of the most rapidly warming regions on Earth. Large environmental changes have occurred as a result of this warming, most notably the retreat and rapid disintegration of some of the floating ice shelves that fringe the Peninsula. Subsequent to the loss of ice shelves, glaciers draining the Peninsula ice sheet have accelerated, contributing to global sea level rise. The forces driving this rapid regional warming are not fully understood, but analysis of limited climatiological data from the region suggests a link between rapid summer warming on the eastern side of the Peninsula and an increase in the strength of the prevailing westerly winds. The strengthening of the westerlies has already been attributed, with some degree of confidence, to atmospheric circulation changes associated with anthropogenic forcing, particularly stratospheric ozone depletion and increases in greenhouse gases. It is thus highly probable that anthropogenic forcing is contributing to the rapid warming of the Peninsula. We propose an integrated programme of field observations, analysis and modelling aimed at understanding of how the westerly winds interact with the mountains of the Antarctic Peninsula and how these interactions control the climate of the eastern side of the Peninsula. Our field observations will be concentrated into a one-month (January 2011) intensive field campaign. During this period, atmospheric flow along a transect across the Antarctic Peninsula mountains at around 67 degrees south will be observed using an instrumented aircraft and four automatic weather stations along the line of the transect. Atmospheric conditions on the upwind (western) and downwind (eastern) sides of the mountains will be measured using balloon-borne radiosondes while the fluxes of energy (solar and terrestrial radiation, turbulent heat fluxes) that drive surface melting will be monitored at a camp on the Larsen Ice Shelf to the east of the Peninsula. In order to obtain a more complete picture of the flow across the Peninsula, we will use these observations in conjunction with the results of high-resolution atmospheric model simulations. Observations and model results will, together, provide new insight into the links between atmospheric flow, orography and surface climate in this region. Having established these links, we will use our new understanding of the controls on regional climate to develop soundly-based future (next 100 years) climate scenarios for this region, using predictions of the changes in large-scale atmospheric flow from the 4th Assessment Report of the Intergovernmental Panel on Climate Change. The results of our work will be of value to many groups of scientists working on environmental change in the Antarctic Peninsula and its wider impacts, including glaciologists, oceanographers and marine and terrestrial biologists. The proposal will also contribute to improving the performance of numerical weather prediction and climate models in mountainous areas generally.