Snow Water Equivalent Accumulation Patterns from a Trajectory Approach over the U.S. Southern Rocky Mountains

Isaac J Y Schrock,Antonio-Juan Collados-Lara,Enrique Morán-Tejeda,Steven R Fassnacht,William E Sanford,Anna K D Pfohl

doi:10.3390/hydrology8030124

Isaac J Y Schrock, Antonio-Juan Collados-Lara + Show 4 more

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https://doi.org/10.3390/hydrology8030124

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Abstract

The spatial characteristics and patterns of snow accumulation and ablation inform the amount of water stored and subsequently available for runoff and the timing of snowmelt. This paper characterizes the snow accumulation phase to investigate the spatiotemporal snow water equivalent (SWE) distribution by fitting a function to the trajectory plot of the standard deviation versus mean SWE across a domain. Data were used from 90 snow stations for a 34-year period across the Southern Rocky Mountains in the western United States. The stations were divided into sub-sets based on elevation, latitude, and the mean annual maximum SWE. The best function was a linear fit, excluding the first 35 mm of SWE. There was less variability with SWE data compared to snow depth data. The trajectory of the accumulation phase was consistent for most years, with limited correlation to the amount of accumulation. These trajectories are more similar for the northern portion of the domain and for below average snow years. This work could inform where to locate new stations, or be applied to other earth system variables.

Highlights

Across the western United States, human existence and economic activity are defined by the availability or scarcity of water [1]
The mean snow water equivalent (SWE) and standard deviation of SWE were computed for the entire domain and the two groups divided by latitude
The latitude-based group divided the SNOTEL stations across the Southern Rocky Mountains (SRM) at 38.75 degrees north latitude into north and south sub-sets, based on regions of homogeneity identified with self-organizing map analyses [31] and correlogram analyses of accumulation slopes [36]

Summary

Introduction

Across the western United States, human existence and economic activity are defined by the availability or scarcity of water [1]. Water resources are becoming more in one of the two extreme states: drought or flood [2]. Urban areas are especially susceptible to both drought and flood [3]. Many of these areas are downstream of mountains, where snow is persistent in the winter [4], with about 22% of the world’s population living downstream of the mountains [5]. Drought conditions have been identified over the southern portions of the SRM (Figure 1)

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