DOI: 10.5281/zenodo.17393408
title: Colorado Cold-Air Pooling Maps and SNOTEL Station Classifications

description: This dataset contains maps of cold-air pooling (CAP) across Colorado at 100m resolution (Colorado_100m.nc) and the region surrounding the East River watershed, CO at 30m resolution (EastRiver_30m.nc). Classifications were determined using a Python implementation of the algorithm originally developed in Lundquist et al., 2008, applied to digital elevation models (DEMs) from the USGS (2024). Additionally, the SNOTEL_CAP_classifications.csv file contains CAP signals for 110 of the 117 Colorado SNOw TELemetry (SNOTEL) weather stations, derived from statistical analysis on observations and the automated algorithm classifications in Colorado_100m.nc.

This dataset is released in support of an upcoming manuscript studying CAP distributions across these two regions (currently in preparation). The two NetCDF (.nc) files are structured as follows:

Variables- elevation: elevation at each pixel (meters) - slope: slope at each pixel (degrees)- rank: proportion of surrounding pixels (within a square of radius r) which are lower in elevation than the given pixel. - curvature: terrain curvature at each pixel (1/m)- CAP: cold-air pooling signal at each pixel. Values: 1 = CAP, 0 = no-signal, -1 = no-CAP.

Coordinates- lon:  longitude (degrees, WGS84)- lat: latitude (degrees, WGS84)- xv_dist: cross-valley distance (meters). A critical input defining the critical radii r in rank and curvature calculations. The SNOTEL_CAP_classifications.csv file is modified from site metadata obtained with the USDA NRCS National Water and Climate Center Air and Water Database Report Generator (https://wcc.sc.egov.usda.gov/reportGenerator). The appended columns include:- EOF CAP Signal: CAP signal derived from empirical orthogonal function (EOF) analysis on recorded daily-minimum temperatures at 110 of Colorado's 117 SNOTEL stations. Negative values indicate CAP; positive values indicate no-CAP.- Algorithm CAP Signal:  CAP classifications for 110 of the 117 Colorado SNOTEL stations derived from the values in Colorado_100m.nc (3000 m cross-valley distance). Values: 1 = CAP, 0 = no-signal, -1 = no-CAP.

Files- Colorado_100m.nc: CAP classifications at 100m-resolution across the Colorado mountains for cross-valley distances from 10,000m to 1,000m (every 500m). Users may select the value which best describes their region of interest. - EastRiver_30m.nc: CAP classifications at 30m-resolution across terrain surrounding the East River watershed for a single cross-valley distance of 3,000m.  - SNOTEL_CAP_classifications.csv: CAP classifications for 110 of the 117 Colorado SNOTEL Stations determined by EOF analysis (column titled EOF CAP Signal) and an automated algorithm (column titled Algorithm CAP Signal).

For further detail on algorithm design and function, including the calculation of rank and curvature, CAP classification criteria, and choice of cross-valley distance, please refer to Lundquist et al., 2008 or the linked GitHub repository. In-depth discusson on algorithm implementation and constraints, EOF classifications, and algorithm-EOF disagreement will be released in an upcoming manuscript.Version 1.1.0 added the SNOTEL_CAP_classifications.csv file to the dataset.For questions, please contact jcramblitt@berkeley.edu.