Antarctica on the scales: Present-day mass balance of the Antarctic Peninsula from time-variable gravity field measurements

这项研究的主题是利用重力恢复和气候实验(GRACE)的时变重力测量数据，并辅之以来自现场GPS站点和Envisat、Cyrosat和ICESat等测高任务的数据，来研究南极半岛今天的冰块平衡。该地区是地球上变暖最快的地区之一，在过去的几十年里发生了戏剧性的变化，包括几个冰架的完全坍塌。每隔30天，GRACE就会提供一个重力场，其中包含的信息空间尺度可达~400公里，精度接近2厘米深的水面。在南极洲上空，GRACE将捕捉到冰块的变化，尽管这些冰块将被大气、附近海洋的质量变化以及固体地球的冰后反弹(PGR)所污染。由于其相对容易进入，南极半岛在大气压力和海洋质量变化方面相对知名，尽管该地区的数值海洋潮汐模型在很大程度上仍未得到验证，误差将混入GRACE时间序列。因此，研究将侧重于：1)使用新的和现有的全球定位系统观测对PGR进行测量，以限制反弹模型；2)使用陆上GPS海洋潮汐负荷变形估计来验证数值潮汐模型，然后将其应用于GRACE时间序列；以及3)使用经校正的GRACE测量确定冰块的季节性和长期变化率；4)酌情加强雷达和激光测高。这些措施将对气候变暖对南极大陆的影响提供独立的制约。

The subject of this study is the present-day ice mass balance of the Antarctic Peninsula using time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) complemented by data from in situ GPS sites and altimetric missions such as EnviSat, CyroSat and ICESat. This region is amongst the fastest warming regions on Earth and dramatic changes have been occurring over the past few decades, including the complete collapse of several ice shelves. Every 30 days GRACE delivers a gravity field with information at spatial scales down to ~400 km, with an accuracy approaching 2 cm of water. Over Antarctica GRACE will capture ice mass changes, although these will be contaminated by mass variations in the atmosphere, in nearby oceans, and due to post-glacial rebound (PGR) in the solid earth. Due to its relative ease of access, the Antarctic Peninsula is relatively well-known as regards atmospheric pressure and oceanic mass variations although numerical ocean tide models are still largely unverified in this region and errors will alias into the GRACE time series. The research will therefore focus on i) PGR measurements using new and existing Global Positioning System (GPS) observations to constrain rebound models; ii) verification of numerical tide models using onshore GPS ocean tide loading deformation estimates followed by application to the GRACE time series; and iii) the determination of seasonal and secular rates of ice mass change using corrected GRACE measurements; with iv) enhancement from radar and laser altimetry as appropriate. These will provide independent constraints on the effects of a warming climate on the Antarctic continent.