Doctoral Dissertation Research: Quantitative Hydraulic Models for Jokulhlaup-Type Outflow Channels on Mars: Application of Earth Analogues, Geomorphology, and Remote Sensing

对行星体的地球类似物的研究主要用于测试关于可能与地球上类似的现象的假设。 这篇博士论文的研究使用地球的类似物来测试这一假设，即火星上的大规模河流通道及其观测到的地貌特征是由地表水流和地下水喷发的组合形成的。这些类型的喷发被称为“Jökulhlaup”，来自冰岛术语，描述了从冰川后面或下面突然释放大量水。在地球表面也有类似的地点，包括华盛顿东部的切尼-帕卢斯疤地（与米苏拉冰川湖有关）和冰岛瓦特纳冰川的Jökulsá á Fjöllum通道。这些地球类似物是由地质学上过去的jökulhlaup型爆发洪水形成的，因此应该提供对火星过程的见解，其中源盆地的大小不足以创造所观察到的河流和地貌特征，特别是考虑到较低的行星引力常数。这项研究包括利用空间遥感、地面实地测量以及对地球和火星上的自然现象进行一维、二维和三维水文和水力建模。收集和处理遥感数据将为水文和水力模型提供所需的河道物理特性，然后将通过对米苏拉冰川湖古森林带和冰岛的两个地球模拟研究区的河道进行广泛的实地测绘加以核实。 一个独特的技术推导出的表面粗糙度的水力特性，基岩的热惯性和传导性的基础上，将进行测试。这项工作的目的是估计在地球上形成jökulhlaup型河流通道和地貌特征所需的平均流速、峰值流量和功率，以便将这些模型应用于火星上的类似通道。其次，目标是定量地确定火星上创造这些特征所需的水量，因为重力常数小于地球的一半。这项研究将为火星的水文和地质历史提供新的定量见解。这项工作的结果将传达有关塑造火星河流地貌所需水量的定量信息，并为其地质和水文历史提供重要的数据点。 这项研究将提供关键的洞察力，以了解在火星上创造大量外流通道的机制，以及气候变化如何影响这些过程。 同样，水文和水力模型的灾难性流动制度和地表和地下水源之间的相互作用，在地球类似的网站，特别是在那些地区受冰川过程的影响最大，将提供一个观点的过程，可能会发生由于我们自己的气候变化。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Studies of Earth analogues of planetary bodies are used primarily to test hypotheses about phenomena that may be similar to those on Earth. This doctoral dissertation research uses Earth analogues to test the hypothesis that the massive fluvial channels on Mars and their observed geomorphic features were formed by a combination of surface water flow and eruptions from ground water confined by a cryolithospheric layer. These types of eruptions are termed "Jökulhlaup", from an Icelandic term that describes an abrupt release of massive amounts of water from behind or beneath a glacier. There are also similar locations on the Earth's surface, including the Cheney-Palouse Scablands in eastern Washington (associated with Glacial Lake Missoula) and the Jökulsá á Fjöllum channel at Vatnajökull glacier in Iceland. These Earth analogues were formed by jökulhlaup-type outburst floods in the geologic past, and so should provide insights into processes on Mars, where the size of the source basins is not sufficient to create the fluvial and geomorphic features observed, especially given the lower planetary gravitational constant. This research encompasses the use of space-borne remote sensing, ground-based field measurements, and one, two and three-dimensional hydrologic and hydraulic modeling of natural phenomena on Earth and Mars. Collecting and processing remote sensing data will provide the fluvial channel physical properties needed for the hydrologic and hydraulic models, which then will be verified by extensive field mapping of the fluvial channels at two Earth analogue study areas, in the Glacial Lake Missoula paleoflood zone and in Iceland. A unique technique for deriving the hydraulic property of surface roughness, based on bedrock thermal inertia and conductivity, will be tested. The objective of this work is to estimate the mean flow velocity, peak discharge and power needed to create the jökulhlaup-type fluvial channels and geomorphic features on Earth in order to apply these models to similar channels on Mars. Secondly, the goal is to establish quantitatively the amount of water needed on Mars to create these features given a gravitational constant less than half that of the Earth's. This research will provide new quantitative insight into the hydrologic and geologic history of Mars.The results of this work will convey quantitative information about the amount of water needed to sculpt the fluvial landforms on Mars and provide a significant datapoint to its geologic and hydrologic past. This research will provide key insight into the mechanisms that created the massive outflow channels on Mars and how climate change may have influenced these processes. Similarly, hydrologic and hydraulic modeling of catastrophic flow regimes and the interactions between surface and subsurface water sources at Earth analogues sites, particularly at those areas most influenced by glacial processes, will provide a viewpoint to the processes that may occur due to our own climate change. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.