New approaches to address scaling issues for lateral flow of water in a layered snowpack

Dr. Ryan W.韦伯已被授予NSF博士后奖学金，在科罗拉多大学博尔德分校和劳伦斯伯克利国家实验室开展研究和教育计划。韦伯博士将致力于更好地了解积雪中水的横向流动。研究人员将研究在雪中发生的毛细和/或渗透性屏障的形成和尺度，以及实验室尺度参数作为建模输入的适用性。这项调查将提供对春季融雪过程中发生在多种环境中的水文过程的基本见解。这项研究产生的数据将通过水文数据库CUAHSI HIS广泛提供。除了研究，研究者还将参与教育活动，如指导本科生和研究生进行大量的研究机会，并在科罗拉多大学共同教授水文学课程。融雪过程中发生的动态过程创造了一个复杂的环境，其中水的横向流动已被证明具有水文意义，尽管难以建模。为了准确地模拟这一过程，在适当的尺度表示积雪特性是必要的。因此，该研究旨在：1）确定在山坡尺度上产生显著侧向流所需的相邻积雪层之间的粒度和密度的变化，2）确定驱动物理（地形，土地覆盖等）。和气候条件要求，以产生这些障碍，3）产生一个二维的数值模型，能够模拟分层多孔介质随时间变化的属性，和4）确定如何合适的实验室规模的调查雪的属性是在山坡规模的应用。在博尔德溪CZO和尼沃特岭LTER中，将使用全球定位系统和探地雷达的科学状态方法收集跨越海拔梯度的数据，用于雪中液态水含量的非破坏性测量，用于较大规模流路开发调查的染料示踪剂实验，用于隔离坡度影响的实验室实验，以及用于放大先前开发的实验室规模参数的逆建模。

Dr. Ryan W. Webb has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at the University of Colorado - Boulder and Lawrence Berkeley National Laboratory. Dr. Webb will aim at better understanding the lateral flow of water within a snowpack. The investigator will study the formation and scales at which capillary and/or permeability barriers occur in snow, and the applicability of laboratory scale parameters as input for modeling. The investigation will provide fundamental insights into hydrological processes that occur during spring snowmelt in multiple environments. Data generated from this research will be made widely available through the hydrologic database CUAHSI HIS. In addition to research, the investigator will engage in education activities like mentoring undergraduate and graduate students in numerous research opportunities and co-teaching a hydrology course at the University of Colorado.The dynamic processes that occur during snowmelt create a complex environment where the lateral flow of water has been shown to be hydrologically significant, though difficult to model. To model this process accurately, representation of snowpack properties at appropriate scales is necessary. Thus, the research seeks to: 1) determine the variability in grain size and density between adjacent snowpack layers required to produce significant lateral flow at the hillslope scale, 2) determine the driving physical (topographic, land cover, etc.) and climatic conditions required to produce these barriers, 3) produce a two-dimensional numerical model capable of simulating layered porous media with temporally varying properties, and 4) determine how suitable laboratory scale investigations of snow properties are for applications at the hillslope scale. Data will be collected across elevation gradients in the Boulder Creek CZO and Niwot Ridge LTER using state of the science Global Positioning Systems and Ground Penetrating Radar methods for non-destructive measurements of liquid water content in snow, dye tracer experiments for larger scale flow path development investigations, laboratory experiments for isolation of the effect of slope, and inverse modeling for upscaling previously developed laboratory scale parameters.