Improved models of West Antarctic glacial isostatic adjustment through new crustal motion data

该项目旨在解决目前南极西部冰盖对全球海平面上升的影响方面的不确定性。这些估计数主要来自空间大地测量（测高或时变重力）测量，GRACE卫星使命提供的时变重力数据是能够确定整个冰盖冰量平衡的唯一技术。精确校正总质量变化（测量GRACE），以获得冰质量的变化，但是，复杂的缺乏信心，准确校正冰川均衡调整（GIA）。事实上，最近公布的对南极洲西部冰量变化的估计被GIA模型中目前的不确定性所淹没。全球定位系统的时间序列对全球影响评估提供了重要的限制，而且实际上已在许多关键地点安装。然而，目前的GPS站点网络，虽然允许分离非常不同的GIA模型，但过于稀疏，无法提供产生改进模型所需的严格约束，因此需要GPS站点的高空间分辨率。特别是，南极南部的半岛/伦讷冰架包含一个非常大的GRACE信号，但目前的站密度太稀疏，明确地确定重力变化的起源。该地区还有更多合适的岩石露头可用于额外的数据收集，并且在那里放置新的、间隔更密的连续地点将提供所需的限制。在这里，我们建议通过新收集的GPS数据对南极GIA模型进行改进，从而使我们能够计算新的准确和精确的估计，从南极洲西部的冰量对海平面上升的贡献。

This project addresses the current uncertainty in the present-day contribution of the West Antarctic Ice Sheet to global sea level rise. These estimates are primarily derived from space geodetic (altimetry or time-variable gravity) measurements, with time-variable gravity data from the GRACE satellite mission the only technique capable of determining ice mass balance for the entire ice sheet. Accurate correction of total mass change (measured by GRACE) to obtain ice mass change is, however, complicated by a lack of confidence in accurately correcting for glacial isostatic adjustment (GIA). Indeed, recent published estimates of ice mass change for West Antarctica are swamped by the present uncertainty in GIA models. Global Positioning System (GPS) time series offer important constraints on GIA and, indeed, have been installed in many of the critical locations. However, the current network of GPS sites, whilst allowing separation of wildly different GIA models, is too sparse to provide the tight constraints required for producing improved models / for that a high spatial resolution of GPS sites is required. In particular, the southern Antarctic Peninsula/Ronne Ice Shelf contains a very large GRACE signal, but the current station density there is too sparse to unambiguously determine the origin of the gravity change. Further suitable rock outcrops are available in this region for additional data collection and situating there new, more densely spaced, continuous sites would provide the required constraints. Here, we propose to place improved constraints on an Antarctic GIA model through newly collected GPS-data, thereby allowing us to compute new accurate and precise estimates of ice mass contributions to sea level rise from West Antarctica.