Quantifying Surface Processes above Buried Ice in Antarctica: Implications for Terrestrial Climate Change and Glaciation on Mars

学术价值：认识到上新世和中新世冰川埋藏在干燥山谷最寒冷部分的升华冰盖下，可能还埋藏在横跨北极山脉的其他地方，这为建立数百万年的气候和大气演变记录打开了可能性。PI建议对穆林斯冰川进行定量分析，穆林斯冰川是最古老的被碎片覆盖的高山冰川。初步工作表明，古代大气被困在穆林斯冰川中，然而，地貌过程以意想不到的方式改变了冰川。在之前的工作中，PI开发了定义这些过程的定性模型，在本提案中，他寻求通过定量建模和更高级别的数据获取来量化和测试这些模型。要解决的问题包括：水蒸气扩散、大气-地表相互作用和冰层特性的哪些方面促进了埋藏冰的长期保存？冰面上的升华冰盖和升华多边形会如何影响地下冰的损失和冰川冰中滞留气体的组成？升华多边形的形态参数能揭示地下冰的深度和纯度吗？如果是这样的话，这些形态测量参数能否被用来绘制地球和火星其他地方未被探测到的埋藏冰层的地图？在数百万年前的时间尺度上，穆林斯冰川中浓度/风格的冰川碎屑的浓度/风格的变化能告诉我们什么关于当地环境变化的信息？为了回答这些问题，PI提出了许多关于穆林斯冰川的实验。更广泛的影响：这项工作将量化地表过程，这些过程可能是最长的大气演变和气候变化记录。这项研究对于理解火星上埋藏的冰具有重要意义。这项研究将支持一名研究生和本科生。PI将继续他与洛杉矶山谷社区学院系统的成功外联活动，并进一步发展他在波士顿大学的数字图像分析实验室，该实验室向来访的学生、教师、家长和更广泛的社区中对南极洲感兴趣的人展示他的南极和行星工作的3D。

Intellectual Merit: The recognition that Pliocene and Miocene age glacier ice lies buried beneath sublimation tills in the coldest parts of the Dry Valleys, and likely elsewhere in the Transantarctic Mountains, opens up the possibility of establishing multi-million year records of climate and atmospheric evolution. The PI proposes a quantitative analysis of the Mullins Glacier, the oldest debris-covered alpine glacier. Preliminary work suggests that ancient atmosphere is trapped within Mullins Glacier, however, geomorphic processes, have modified the glacier in unforeseen ways. In prior work, the PI developed qualitative models defining these processes, and in this proposal he seeks to quantify and test these models through quantitative modeling and higher-level data acquisition. Questions to be addressed include: What aspects of vapor diffusion, atmosphere-surface interactions, and till characteristics encourage long-term preservation of buried ice? How might sublimation tills and sublimation polygons at the ice surface influence subsurface ice loss and the composition of trapped gases in glacier ice? Do morphometric parameters of sublimation polygons shed light on the depth and purity of subsurface ice? If so, can these morphometric parameters be used to map undetected buried-ice deposits elsewhere on Earth and Mars? What can variations in the concentration/ style englacial debris in Mullins Glacier tell us about local environmental change over multi-million year old time scales? To answer these questions, the PI proposes numerous experiments for Mullins Glacier.Broader impacts: This work will quantify surface processes that modify what may be the longest record of atmospheric evolution and climate change. This research has relevance for understanding buried ice on Mars. The research will support a graduate student and undergraduates. The PI will continue his successful outreach activities with the Los Angeles Valley Community College system and in further developing his digital image analyses lab at Boston University, which showcases his Antarctic and planetary work in 3D to visiting students, faculty, parents, and those interested in Antarctica in the wider community.