Continuation of the LARISSA Continuous GPS Network in View of Observed Dynamic Response to Antarctic Peninsula Ice Mass Balance and Required Geologic Constraints

鉴于观测到的对南极半岛冰块平衡的动态响应和所需的地质限制，LARISSA 连续 GPS 网络的延续

• 批准号: 1433140
• 负责人: Eugene Domack
• 金额: $ 3.75万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1433140&HistoricalAwards=false
• 关键词: Continuation; LARISSA; Continuous; GPS; Network

This project aims to identify which portions of the glacial cover in the Antarctic Peninsula are losing mass to the ocean. This is an important issue to resolve because the Antarctic Peninsula is warming at a faster rate than any other region across the earth. Even though glaciers across the Antarctic Peninsula are small, compared to the continental ice sheet, defining how rapidly they respond to both ocean and atmospheric temperature rise is critical. It is critical because it informs us about the exact mechanisms which regulate ice flow and melting into the ocean. For instance, after the break- up of the Larsen Ice Shelf in 2002 many glaciers began to flow rapidly into the sea. Measuring how much ice was involved is difficult and depends upon accurate estimates of volume and area. One way to increase the accuracy of our estimates is to measure how fast the Earth's crust is rebounding or bouncing back, after the ice has been removed. This rebound effect can be measured with very precise techniques using instruments locked into ice free bedrock surrounding the area of interest. These instruments are monitored by a set of positioning satellites (the Global Positioning System or GPS) in a continuous fashion. Of course the movement of the Earth's bedrock relates not only to the immediate response but also the longer term rate that reflects the long vanished ice masses that once covered the entire Antarctic Peninsula?at the time of the last glaciation. These rebound measurements can, therefore, also tell us about the amount of ice which covered the Antarctic Peninsula thousands of years ago. Glacial isostatic rebound is one of the complicating factors in allowing us to understand how much the larger ice sheets are losing today, something that can be estimated by satellite techniques but only within large errors when the isostatic (rebound) correction is unknown.The research proposed consists of maintaining a set of six rebound stations until the year 2016, allowing for a longer time series and thus more accurate estimates of immediate elastic and longer term rebound effects. It also involves the establishment of two additional GPS stations that will focus on constraining the "bull's eye" of rebound suggested by measurements over the past two years. In addition, several more geologic data points will be collected that will help to reconstruct the position of the ice sheet margin during its recession from the full ice sheet of the last glacial maximum. These will be based upon the coring of marine sediment sequences now recognized to have been deposited along the margins of retreating ice sheets and outlets. Precise dating of the ice margin along with the new and improved rebound data will help to constrain past ice sheet configurations and refine geophysical models related to the nature of post glacial rebound. Data management will be under the auspices of the UNAVCO polar geophysical network or POLENET and will be publically available at the time of station installation. This project is a small scale extension of the ongoing LARsen Ice Shelf, Antarctica Project (LARISSA), an IPY (International Polar Year)-funded interdisciplinary study aimed at understanding earth system connections related to the Larsen Ice Shelf and the northern Antarctic Peninsula.

该项目旨在确定南极半岛的冰川覆盖物的哪些部分正在向海洋失去质量。这是解决的重要问题，因为南极半岛的变暖速度比地球上任何其他地区都要快。尽管与大陆冰盖相比，整个南极半岛的冰川很小，但确定它们对海洋和大气温度的响应速度均升高至关重要。这很关键，因为它告诉我们调节冰流并融化到海洋的确切机制。例如，在2002年拉尔森冰架分解后，许多冰川开始迅速流入海中。测量涉及多少冰是困难的，并且取决于数量和面积的准确估计。提高估计值的准确性的一种方法是测量地壳的反弹或弹跳后，去除冰的速度。可以使用非常精确的技术来测量这种反弹效果，并使用锁定在感兴趣区域的无冰基岩中的仪器。这些仪器是通过连续的一组定位卫星（全球定位系统或GPS）监控的。当然，地球基岩的移动不仅与立即的反应有关，而且还涉及长期的冰质量，这反映了长期消失的冰块，这些冰块曾经覆盖了整个南极半岛？因此，这些反弹测量值也可以告诉我们数千年前覆盖南极半岛的冰量。冰川等静压反弹是使我们能够理解今天较大的冰盖损失多少的复杂因素之一，这可以通过卫星技术估算，但仅在尚不清楚的等速器（反弹）校正时才在大误差中。拟议的研究拟议的是，直接保持六年级的弹性效果，因此可以更长时间地估算一个较长的时间效应，从而更长时间地估算了一个更长的时间效应，从而更长时间地估算了一个较长的依次效果，从而更加准确地估算了一系列的效果。它还涉及建立两个另外两个GPS站，这些GPS电台将着重于限制过去两年来测量所建议的反弹的“牛眼”。此外，还将收集更多的地质数据点，这将有助于从最后一次冰川最大的冰盖衰退期间重建冰盖边缘的位置。这些将基于现在被认为已被沿撤退的冰盖和插座边缘沉积的海洋沉积物序列的芯。冰缘的精确约会以及新的和改进的篮板数据将有助于限制过去的冰盖配置，并完善与冰川后反弹性质有关的地球物理模型。数据管理将在UNAVCO Polar地球物理网络或Polenet的主持下，并将在车站安装时公开使用。该项目是正在进行的Larsen冰架的小规模扩展，南极项目（Larissa）是一项由IPY（国际极性年）资助的跨学科研究，旨在了解与Larsen Ice Shelf和Norther Northers Antarecliac Peninsula相关的地球系统联系。