IPY: Stability of Larsen C Ice Shelf in a Warming Climate

Steffen/0732946该奖项支持与智利和荷兰的合作伙伴进行的实地实验，以确定Larsen C冰架应对气候变化的健康和稳定状态。南极半岛正在发生重大的冰川学和生态变化，以应对气候变暖，其速度是全球平均速度的6倍。继1995年拉森A冰架和2002年拉森B冰架的崩溃之后，用陆地冰滋养它们的出口冰川大幅加速，失去了不成比例的冰到海洋中。再往南，更大的拉森C冰架正在变薄，十多年来收集的测量数据表明，它注定要破裂。 该项目的智力价值将是有助于增进对南极地区之一的科学了解，目前该地区正在发生最重大的变化。该项目是在南极半岛开展的一系列国际极地年活动的核心。它将在遥远但具有全球意义的冰川学环境中产生国际合作、仪器联网、青年科学家教育、参考数据和科学分析的遗产。该项目更广泛的影响将是解决南极洲对海平面上升的影响，并通过网上直播进展、数据收集、可视化和分析，向科学家、学生、非专业公众、新闻界和媒体提供南极洲气候和冰动态的实况监测。 现有的数据将与新的测量相结合，以评估哪些物理过程控制着冰架的弱化，是否有可能破裂，并提供基线数据来量化破裂的后果。实地活动将包括利用全球定位系统进行测量、安装自动气象站、进行探地雷达测量、收集浅层雪核和进行温度测量。这些数据将用于确定冰架对各种现象（海潮、冰山崩解、冰锋后退和断裂、气候条件的时间序列、冰架的结构特征和底部融化状况、以及积雪收集融水并随后形成使冰架过度加深和削弱的水池的能力）的动态反应。这项工作将补充对遥感数据、冰架数值模型和控制方法的分析，这些分析是独立供资的，目的是对气候变化中冰架的演变进行更全面的分析。

Steffen/0732946This award supports a field experiment, with partners from Chile and the Netherlands, to determine the state of health and stability of Larsen C ice shelf in response to climate change. Significant glaciological and ecological changes are taking place in the Antarctic Peninsula in response to climate warming that is proceeding at 6 times the global average rate. Following the collapse of Larsen A ice shelf in 1995 and Larsen B in 2002, the outlet glaciers that nourished them with land ice accelerated massively, losing a disproportionate amount of ice to the ocean. Further south, the much larger Larsen C ice shelf is thinning and measurements collected over more than a decade suggest that it is doomed to break up. The intellectual merit of the project will be to contribute to the scientific knowledge of one of the Antarctic sectors where the most significant changes are taking place at present. The project is central to a cluster of International Polar Year activities in the Antarctic Peninsula. It will yield a legacy of international collaboration, instrument networking, education of young scientists, reference data and scientific analysis in a remote but globally relevant glaciological setting. The broader impacts of the project will be to address the contribution to sea level rise from Antarctica and to bring live monitoring of climate and ice dynamics in Antarctica to scientists, students, the non-specialized public, the press and the media via live web broadcasting of progress, data collection, visualization and analysis. Existing data will be combined with new measurements to assess what physical processes are controlling the weakening of the ice shelf, whether a break up is likely, and provide baseline data to quantify the consequences of a breakup. Field activities will include measurements using the Global Positioning System (GPS), installation of automatic weather stations (AWS), ground penetrating radar (GPR) measurements, collection of shallow firn cores and temperature measurements. These data will be used to characterize the dynamic response of the ice shelf to a variety of phenomena (oceanic tides, iceberg calving, ice-front retreat and rifting, time series of weather conditions, structural characteristics of the ice shelf and bottom melting regime, and the ability of firn to collect melt water and subsequently form water ponds that over-deepen and weaken the ice shelf). This effort will complement an analysis of remote sensing data, ice-shelf numerical models and control methods funded independently to provide a more comprehensive analysis of the ice shelf evolution in a changing climate.