The Antarctic Ice Sheet Large Ensemble (AISLENS) Project: Assessing the Role of Climate Variability in Past and Future Ice Sheet Mass Loss

未来海平面上升预测的不确定性部分来自冰盖融化，这是由于冰盖附近海洋和大气温度的不可预测变化造成的。南极冰盖大包围（AISLENS）项目将使用最先进的建模技术，估计最近和未来几个世纪可能由这种气候变化导致的南极冰盖融化的范围。AISLENS项目还将通过向更广泛的气候和冰川学社区提供模型输出作为开放产品来促进研究。该项目将支持一名早期职业教师，并为一名研究生、博士后和本科生提供跨学科培训。作为该项目的一部分，还将开设一门关于“海平面上升和沿海工程”的本科课程，使地球科学和土木工程专业的学生在一个跨学科的环境中聚集在一起，并促进他们在海平面科学和沿海适应方面的教育。 这将是在美国东南部的地理背景下，最集中的脆弱性，在美国海平面上升的地区。拟议的研究的主要目标是了解和量化的作用，内部气候变化的驱动冰损失从南极冰盖在最近的过去和未来。AISLENS项目将包括对1950年至2300年期间南极冰盖演变的数百次模拟，这些演变是由气候的实际变化造成的，包括降雪和海洋和大气温度波动造成的融化。南极气候强迫的合理实现将产生随机模拟的输出从能源亿级地球系统模型（E3SM）在过去和未来的排放情景。这些对气候变化的认识将被用来推动MPAS奥尔巴尼陆地冰（MALI）模型，这是一个最先进的南极冰盖冰流模型。在本项目中，将使用AISLENS进行不确定性和归因分析。在不确定性分析中，将对南极冰盖未来演变模拟中的集合扩散演变进行系统分解，以确定气候变率的哪些时空尺度对未来冰盖预测的不确定性贡献最大。在归因分析中，将对最近南极冰损失的一系列卫星观测结果与AISLENS模拟中模拟的涵盖最近过去的南极冰损失内部变化包络进行比较。这项分析将提供最近的观测表明南极气候强迫的显着变化的背景下，并提供了一个可能的路径进行强大的统计推断研究所观察到的冰盖changes.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Uncertainty in projections of future sea level rise comes, in part, from ice-sheet melting under the influence of unpredictable variations in ocean and atmospheric temperature near ice sheets. Using state-of-the-art modeling techniques, the Antarctic Ice Sheet Large Ensemble (AISLENS) Project will estimate the range of possible Antarctic Ice Sheet melt during the recent past and over the next several centuries that could result from such climate variations. The AISLENS Project will also facilitate research by providing modeling output as an open product to the broader climate and glaciology communities. The project will support an early career faculty member, and interdisciplinary training for a graduate student, postdoctoral fellow and undergraduate student. As a part of this project, an undergraduate course on "Sea Level Rise and Coastal Engineering" will be also developed, bringing together Earth Science and Civil Engineering students in an interdisciplinary setting and contributing to their education in sea level science and coastal adaptation. This will be done in the geographic context of the Southeastern US, the region of most concentrated vulnerability to sea-level rise in the US.The primary goal of the proposed research is to understand and quantify the role of internal climate variability in driving ice loss from the Antarctic Ice Sheet over the recent past and into the future. The AISLENS Project will encompass hundreds of simulations of Antarctic ice sheet evolution from 1950 to 2300 forced by realistic variations in climate, including snowfall and melt from fluctuating oceanic and atmospheric temperatures. Plausible realizations of Antarctic climate forcing will be generated from stochastic emulation of output from the Energy Exascale Earth System Model (E3SM) under past and future emissions scenarios. These realizations of variable climate will be used to force the MPAS Albany Land Ice (MALI) model, a state-of-the-art model of ice flow in the Antarctic Ice Sheet. In this project, AISLENS will be used to conduct uncertainty and attribution analyses. In the uncertainty analysis, the evolution of ensemble spread in simulations of the future evolution of the Antarctic Ice Sheet will be systematically decomposed to determine which temporal and spatial scales of climate variability contribute the most to future ice-sheet projection uncertainty. In the attribution analysis, a range of satellite-based observations of recent Antarctic ice loss will be compared to the envelope of internal variability of Antarctic ice loss simulated in AISLENS simulations encompassing the recent past. This analysis will provide context to recent observations indicating significant variability of Antarctic climate forcing and provide a possible path forward for conducting robust statistical inference studies for observed ice-sheet changes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.