Changing Characteristics of Western US Snowpack
Abstract
In the western US water stored as mountain snowpack comprises a large percentage of the total water needed to meet the region's demands, and it is likely that as the planet continues to warm mountain snowpack will decline. However, detecting such trends in the observational record is challenging because snowpack is highly variable in both space and time, and because the metric often used to quantify mountain snowpack, April 1 snow water equivalent (SWE), is inherently noisy. Here, a method for characterizing mountain snowpack that is based on fitting observed annual cycles of SWE to a gamma distribution probability density function is developed. Analysis of these data show robust trends in the shape of the annual cycle of snowpack in the western US. Specifically, over the 1982-2017 water years, the annual cycle of snowpack is becoming more narrow and less skewed. A narrowing of the annual cycle corresponds to a shrinking of the length of the winter season, primarily because snowpack melting is commencing earlier in the water year. As the annual cycle of snowpack at high elevations tends to be more skewed than at lower elevations, a less skewed shape suggests that snowpack is becoming more characteristic of that at lower elevations.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H31G1962E
- Keywords:
-
- 0736 Snow;
- CRYOSPHEREDE: 0740 Snowmelt;
- CRYOSPHEREDE: 1860 Streamflow;
- HYDROLOGYDE: 1863 Snow and ice;
- HYDROLOGY