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

1245788/Simons该奖项支持一个项目，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空间和时间评估。利用在格陵兰冰盖工作期间开发的技术，这项工作将大大改善先前根据全球“二级”GRACE数据进行的冰量估计。然后将使用更多的原始“一级”数据对南极质量变化进行新的局部反演。这些改进后的估计将用于研究南极洲下地幔中横向变化的粘性结构，通过对正在进行的冰后反弹进行适当校正，将观测到的长期质量变化正确地归因于冰的增加和减少。当GRACE使命已经绘制了地球的地图？自2002年以来，地球重力场的变化，仍然有重大的科学分歧，有多少陆地冰质量已经改变，它已经改变，以及有多少冰损失可能已经加速。这种分歧部分源于不同群体在其数据处理程序中所作的选择。假设的误差结构的精确性质和降噪技术的选择限制了GRACE结果的空间和时间分辨率。 这项工作的智力价值是，它将努力利用重力测量法对南极洲的冰量变化作出最准确和最佳的估计，并将很容易与其他测量技术的估计联系起来。通过将重力测量的估计值与激光测高、干涉合成孔径雷达、全球定位系统和表面质量平衡研究的其他测量值进行比较，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和GRACE社区以及从事南极冰盖质量平衡工作的人的极大兴趣。这项工作的更广泛影响是，它将有助于向社区和公众通报GRACE重力测量等与气候有关的测量的不确定性，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审的期刊上，所有处理软件工具将免费提供给其他人。结果也将以一种公众可以使用的格式提供，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，作为该项目的一部分，将指导本科生。该项目不需要在南极进行实地考察。

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.