Unpacking the Influence of Warming on Hydrological Partitioning in Rain-Snow Transition Zones of the Western United States
Abstract
Annual snowpack within mountainous regions in the Western United States serves as an essential hydrologic resource for downstream communities. Acting as a seasonal hydrologic reservoir, snowpack accumulation and ablation control runoff generation and ecosystem productivity. In the late-fall, winter and early-spring months, over 50% of catchments in the Western US reside within the rain-snow transition zone, making water available in the area vulnerable to climate changing and warming. Snowfall within the rain-snow transition zone is expected to continue to decrease, on average, by 30% over the western United States by mid-21st century. Shifts in precipitation type are linked to shifts in timing of water resource availability and ecosystem activity. There remains a need for mechanistic modeling studies to unpack the effects of shifting precipitation type on hydrologic partitioning in real mountainous catchments.
Utilizing Critical Zone Observatory catchment data to drive the Distributed Hydrology Soil and Vegetation Model (DHSVM), we assess runoff ratios across a range of annual snow fractions. Using observed streamflow data, local and Weather Research and Forecasting (WRF) meteorological data, and national soil and vegetation data at a 20-meter resolution, we manipulate the amount of annual rain and snow via model-based scenarios within a given catchment. By changing annual snow fraction, we explore the catchment response to precipitation type and downstream runoff. Streamflow response provides large implications for water resources and management on both a small and large scale across these mountainous regions.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H11R1697H
- Keywords:
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- 1804 Catchment;
- HYDROLOGYDE: 1807 Climate impacts;
- HYDROLOGYDE: 1812 Drought;
- HYDROLOGYDE: 1816 Estimation and forecasting;
- HYDROLOGY