International Research Fellowship Program: Alluvial Fan Modeling and Applications to Mars Climate

[602159]国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Erin Kraal博士为期18个月的研究奖学金。荷兰乌得勒支大学的Poppe de Boer， George Postma和Maarten Kleinhans。火星的气候历史极其不确定；火星表面的“古气候指标”，如山谷网、流出渠道和湖床，表明一个气候系统能够从当前寒冷、干燥的气候中得到重大突破。为了了解火星的气候历史，我们必须对火星上的水有详细的了解。冲积扇是火星表面的一个特征，它可以让我们深入了解火星上水的历史和作用。冲积扇系统具有离散的侵蚀和沉积区域，并且是“封闭的”，因此可以详细分析沉积物的运移动力学。然而，目前对冲积扇沉积物运输的理解并没有考虑到火星上不同行星重力所必需的重力缩放。因此，要准确评估火星风扇系统中的水和沉积物通量是不可能的。在与M. Kleinhans博士的合作中，PI正在使用她先前编制的冲积扇数据集的数据来限制火星冲积扇的大量水和沉积物运输。为了了解该系统的复杂时间，例如将风化层的产生与排放交织在一起形成观察到的扇，PI正在与de Boer教授合作开发火星冲积扇模型。最后，作为上述理论工作的补充，PI和Postma教授将利用Eurotank进行重力和沉积物缩放实验，以验证陆地上开发的沉积物输运方程在其他行星系统中的应用。通过乌得勒支大学的理论、计算建模和实验专家的结合，他们将前沿的陆地研究整合到一个新的行星数据集中。行星和陆地专业知识的结合将允许对产生火星冲积扇所需的水量和时间尺度进行准确的评估，从而对火星上的水的历史提供重要的限制。

0602159KraalThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support an eighteen-month research fellowship by Dr. Erin Kraal to work with Drs. Poppe de Boer, George Postma and Maarten Kleinhans, at Utrecht University in the Netherlands.The climate history of Mars is extremely uncertain; "paleoclimate indicators" on the Martian surface, such as valley networks, outflow channels, and lake beds, indicate a climate system capable of significant transgressions from the current cold, dry climate. In order to understand Martian climate history, we must have a detailed understanding of water on Mars. Alluvial fans are one Martian surface feature that can lend particular insight into the history and action of water on Mars. Alluvial fan systems have discrete erosional and depositional areas and are "closed", thus allowing for detailed analysis of sediment transport dynamics. However, current understanding of alluvial fan sediment transport does not account for the gravity scaling necessitated by the different planetary gravity on Mars. Therefore, an accurate assessment of water and sediment fluxes in Martian fan systems is not possible. In collaboration with Dr. M. Kleinhans, the PI is using data from her previously compiled alluvial fan data set to constrain bulk water and sediment transport for Martian alluvial fans. In order to understand the complex timing of the system, such as interweaving regolith production with discharge to form the observed fans, the PI is working with Prof. de Boer on developing a Martian alluvial fan model. Finally, complimenting the above theoretical work, the PI and Prof. Postma will use the Eurotank to conduct gravity and sediment scaling experiments to verify the application of the terrestrially developed sediment transport equations to other planetary systems. Using this combination of theoretical, computational modeling, and experimental experts at Utrecht University, they are integrating cutting edge terrestrial research into a new planetary data set. The combination of planetary and terrestrial expertise will permit accurate assessment of the water volume and time scale necessary to produce Martian alluvial fans and, thus, provide important constraints on the history of water on Mars.