Mapping the Evolution of Antarctica's Mass Balance in Space and Time

1245788/ simons该奖项支持一个项目，该项目根据GRACE卫星收集的数据对南极地区的质量通量进行准确和可靠的时空评估。利用在格陵兰冰盖工作期间开发的一项技术，这项工作将大大改善先前根据公开的全球“2级”GRACE数据进行的冰质量估计。更多的原始“一级”数据将被用于对南极质量变化进行新的局部反演。然后，这些改进的估计将用于研究南极洲下面地幔的横向变化粘度结构，通过对正在进行的冰川后反弹进行适当的修正，将观测到的长期质量变化正确地归因于冰的增加和减少。而GRACE任务已经绘制了地球地图？尽管自2002年以来，美国的重力场发生了变化，但在陆地冰质量发生了多少变化，在哪里发生了变化，以及冰的损失可能加速了多少等问题上，科学界仍然存在重大分歧。这种分歧部分源于不同群体在数据处理过程中所做的选择。假设误差结构的精确性和降噪技术的选择限制了GRACE结果的时空分辨率。这项工作的智力价值在于，它将努力利用重力法对南极洲冰质量变化作出最准确和最明确的估计，并将很容易与其他测量技术的估计相联系。通过将重力测量的估计与激光测高、InSAR、GPS和地表质量平衡研究的其他测量结果进行比较，可以更好地限制对未来海平面上升的预测。这项工作的结果将引起大地测量界和GRACE界以及从事南极冰盖物质平衡工作的人们的极大兴趣。这项工作的更广泛的影响是，它将有助于告知社区和公众有关气候相关测量（如GRACE重力测量）的不确定性，同时解释这些测量所表明的气候变化的严重威胁。结果将发表在同行评议的期刊上，所有的处理软件工具将免费提供给其他人。结果还将以一种格式提供，供公众使用，以了解世界上不断变化的冰盖。这项工作将为本科生研究项目提供数据，并且作为该项目的一部分，将指导一名本科生。这个项目不需要在南极进行实地工作。

1245788/SimonsThis award supports a project to undertake an accurate and robust spatial and temporal assessment of the mass flux in the Antarctic region from the data collected by the GRACE satellites. Using a technique developed during work on the Greenland ice sheet, the work will significantly improve on prior ice mass estimates made from public global "Level 2" GRACE data. More raw "Level 1" data will then be used to perform new localized inversions for Antarctic mass changes. These improved estimates will then be used to study the laterally varying viscosity structure in the mantle beneath Antarctica to correctly attribute the observed secular mass change to ice gains and losses by making the appropriate corrections for ongoing post-glacial rebound. While the GRACE mission has mapped Earth?s gravity field since 2002, there is still significant scientific disagreement as to how much terrestrial ice mass has changed, where it has changed, and by how much ice loss may have been accelerating. This disagreement partly stems from the choices made by different groups in their data processing procedures. The precise nature of the assumed error structure and the choice of noise reduction technique limit the spatial and temporal resolution of GRACE results. The intellectual merit of the work is that it will strive to result in the most accurate and best resolved estimate of the ice mass changes in Antarctica using gravimetry, and will be easily related to estimates from other measurement techniques. By comparing the estimates from gravimetry with other measurements from laser altimetry, InSAR, GPS, and surface mass balance studies, better constraints on forecasts of future sea level rise will be possible. The results of this work will be of great interest to the geodetic and GRACE community as well as those who work on Antarctic ice sheet mass balance. The broader impacts of the work are that it will help inform the community and the public about the uncertainty of climate-related measurements such as GRACE gravimetry, while at the same time explaining the serious threat of climate change suggested by these measurements. Results will be published in peer-reviewed journals and all processing software tools will be made freely available to others. Results will also be made available in a format that is useable by the general public to get informed about the world's changing ice sheets. This work will provide data for undergraduate research projects and as part of this project an undergraduate student will be mentored. This project does not require field work in the Antarctic.