Winter snowmelt trends over western North America: MATLAB code for analysis and figure creation.

This is MATLAB code used to conduct the analysis necessary to create the figures for the article "Winter melt trends portend widespread declines in snow water resources" published in 2021 in Nature Climate Change by Musselman, Addor, Vano and Molotch. DOI: 10.1038/s41558-021-01014-9

Written by Keith Musselman. Last updated on February 17, 2021.

The code loads and analyzes daily snow water equivalent (SWE) observations made at 1,065 snowpack telemetry stations in western North America for the period 1960 - 2019. Long-term trends and patterns in snowmelt and SWE metrics are assessed. Monthly mean air temperature and total precipitation were obtained from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) for 1979 – 2019 (PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu, last accessed 10 June 2020). These gridded data were extracted for all snow telemetry stations in the contiguous U.S. and used to investigate the roles of cold season (i.e., November, December, January, February, and March) temperature and precipitation in influencing interannual variations in snowmelt and SWE metrics.

A user must first unzip the downloaded file and install a number auxiliary functions (beyond the basic MATLAB toolbox and the Mapping Toolbox). The code is run using the wrapper script analysis_wrapper_MeltTrendsNCC.m. All data, analysis functions, and plotting scripts are provided.