Date of Award

Spring 1-1-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Noah P. Molotch

Second Advisor

Mark Williams

Third Advisor

Peter Blanken

Fourth Advisor

Ben Livneh

Fifth Advisor

Rajagopalan Balaji

Abstract

Snowmelt makes up a large portion of the streamflow in the mountainous western United States. The spatial distribution of snow water equivalent (SWE) can affect the magnitude and timing of the spring and summer runoff represented in the hydrograph. Hence, efforts to improve our understanding of the spatial distribution of SWE are vital for good management of our ecological and water resources. SWE is traditionally monitored at measuring stations spread across the western United States, but these stations have been shown to poorly represent the unsampled areas. Remote sensing from satellites has existed since the 1960s but is still unable to measure SWE at scales relevant for water resources. This research utilizes spatio-temporal datasets to promote the use of historical observations of fractional snow covered area (fSCA) to improve estimates of SWE. First, I show that retrospective models of historical SWE distributions from observed fSCA depletion patterns augment existing ground observations of SWE to improve real-time estimates of SWE in unsampled locations. Second, I show that remotely sensed observations of fSCA improve the temporal transferability of the relationship between topography and SWE. Third, a high resolution spatio-temporal dataset is used to observe depletion curves for the first time and evaluate the topographic controls on the relationship between fSCA and snow depth inherent in these depletion curves. Each of these chapters leverages fSCA as an important component and together imply that fSCA has historically been an underutilized observation. Observations of fSCA are available globally for about three decades but necessitate spatially explicit observations of snow depth or SWE to make the most of this long record. Emerging technologies, such as Light Detection and Ranging (LiDAR) and Ground Penetrating Radar (GPR), that provide high resolution spatio-temporal observations of the snowpack and other environmental variables should continue to be exploited to provide insights regarding the physical processes controlling snow dynamics and more generally our water resources. Future adaptions to climate change rely on improving our understanding of the controlling processes and our ability to monitor them at the relevant scales.

Comments

Sixth advisor: Jeff Deems.

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