TITLE: Cameron Pass, CO Spring 2019: Ground-penetrating radar surveys, snow depths, and snowpits ABSTRACT: This dataset contains snow depths, measurements from snowpits, ground-penetrating radar raw files, and derived liquid water content values collected at Cameron Pass, CO during Spring 2019. Snow depths were measured using a manual probe. Snowpit data includes density and temperature measurements, stratigraphy notes, and weather notes. Ground-penetrating radar was collected using a 1 GHz Sensors & Software ProEx unit coupled to the snow surface. Liquid water content was calculated using the picked two-way travel time from processed ground-penetrating radar, snow densities, and snow depths. CONTACT: Randall Bonnell CONTACT EMAIL: rbonnell@colostate.edu LICENSING INFORMATION: This work is licensed under a Creative Commons Attribution 4.0 International License. https://creativecommons.org/licenses/by/4.0/legalcode RECOMMENDED CITATION: Bonnell, R. and D. McGrath (2021), Cameron Pass, CO Spring 2019: Ground-penetrating radar surveys, snow depths, and snowpits, Mountain Scholar. http://dx.doi.org/10.25675/10217/233636 FILE TYPES AND NAMING CONVENTIONS ============================================================================= File Name Contents _____________________________________________________________________________ MMDDYYYY_ROI_Survey#.dt1 Raw Sensors & Software ground-penetrating radar radargram file MMDDYYYY_ROI_Survey#.hd Raw Sensors & Software ground-penetrating radar header file MMDDYYYY_ROI_Survey#.ini Raw Sensors & Software ground-penetrating radar configuration settings file MMDDYYYY_ROI_Survey#_gps.csv Post-processed WGS84 Latitude/Longitude/ Elevation for ground-penetrating radar traces MMDDYYYY_ROI_depths.csv Snow depths with associated WGS84 UTM Zone 13 Easting/Northing MMDDYYYY_ROI_snowpit.xlsx Snowpit height, density and temperature at 10 cm intervals, and stratigraphy notes MMDDYYYY_ROI_snowpit.csv Snowpit height, density and temperature at 10 cm intervals, and stratigraphy notes, converted to .csv format for preservation purposes MMDDYYYY_ROI_Survey#_LWC.csv Liquid water content calculated from snowpit densities, snow depths, and processed ground- penetrating radar. We used the equation from Roth et al. (1990) for the calculations. ______________________________________________________________________________ MM = Two-digit month when data was observed DD = Two-digit day when data was observed YYYY = Four-digit year when data was observed ROI = Region of interest, either North Transect, Meadow Transect, or South Transect Survey# = Time of day when data was observed, 1 = Morning, 2 = Midday, 3 = Evening ______________________________________________________________________________ Total Number of files = 259 SPATIAL COVERAGE ============================================================================== Northernmost Latitude = 40.52°N Southernmost Latitude = 40.51°N Easternmost Longitude = 105.88°W Westernmost Longitude = 105.90°W TEMPORAL COVERAGE ============================================================================== Surveyed Dates Include (YYYY-MM-DD): 2019-04-05 2019-04-25 2019-05-17 2019-06-03 2019-06-04 2019-06-10 2019-06-19 FILE HEADERS ============================================================================== MMDDYYYY_ROI_depths.csv Header Description _____________________________________________________________________________ UTM_Easting(m) WGS84 UTM Easting in meters; EPSG: 32613 UTM_Northing(m) WGS84 UTM Northing in meters; EPSG: 32613 UTM_Zone WGS84 UTM two digit zone in northern hemisphere. EPSG: 32613 SnowDepth(cm) Snow depth in centimeters, measured with a SnowMetrics depth probe. Precision is 1 cm. MMDDYYYY_ROI_Survey#_LWC.csv Header Description _____________________________________________________________________________ IntervalEdge Identifies the edges of the 9 m intervals that liquid water content and snow depths were averaged along. UTM_Easting_m WGS84 UTM Easting in meters; EPSG: 32613 UTM_Northing_m WGS84 UTM Northing in meters; EPSG: 32613 UTM_Zone WGS84 UTM two digit zone in northern hemisphere. EPSG: 32613 SnowDepth_m The average of 4 manual snow depths within the 9 m interval. LWC_vol Liquid water content as a volumetric quantity calculated along 9 m intervals. MMDDYYYY_ROI_snowpit.xlsx Header Description _____________________________________________________________________________ Location The region the snowpit was dug in. Site The site of the snowpit. Either Meadow Transect, North Transect, or South Transect. Surveyors The person/s who conducted measurements and/or took notes. Date Date, listed in month/day/year format Time (MDT) Time of day, given in Mountain Daylight Time Comments Additional observations made in the snowpit Snowpit Height (cm) The height above the ground of the snow surface, measured in centimeters. Air Temperature (°C) The temperature of the air when the snowpit was opened, measured in degrees Celsius. Latitude (DD) Latitude in decimal degrees. WGS84; EPSG: 4326 Longitude (DD) Longitude in decimal degrees. WGS84; EPSG: 4326 Height above ground Where the measurement was taken in the snowpit. measured in centimeters. Snow Density Measured using a 1000 cubic centimeter wedge cutter. Units are kilograms per cubic meter. Temperature (°C) Temperature taken in the snow. Units are degrees Celsius. Stratigraphy Comments The locations of different stratigraphic layers in the snowpit. Noted intervals include ice layers, melt- freeze crusts, and manual estimations of water content. Weather Observations Observations of the weather at the time when the snowpit was opened. Observations include precipitation type and rate, cloud cover and wind conditions, ground conditions, and estimations of tree canopy cover. MMDDYYYY_ROI_Survey#_gps.csv Header Description _____________________________________________________________________________ latitude Latitude in decimal degrees. WGS84; EPSG: 4326 longitude Longitude in decimal degrees. WGS84; EPSG: 4326 altitude Elevation in meters. WGS84 Ellipsoid tracenumber This is the trace number recorded on the radargram UNCERTAINTY, PRECISION, and ACCURACY OF MEASUREMENTS ============================================================================== Snow densities were measured using a scale with a precision of 1 g. Calculated liquid water content has an uncertainty of ±2.0 vol. %. This was calculated from comparisons between snow depths derived from ground- penetrating radar and manually acquired snow depths. The methodology is further outlined in the quality control section. METHODS ============================================================================== Ground-penetrating radar was collected using a Sensors & Software ProEx 1 GHz set-up mounted in a sled. Data was processed in ReflexW Software (version 9.0). Snow depths were collected using a SnowMetrics Snow Depth Probe. Snow densities were collected using a 1000 cubic cm wedge cutter in a snowpit. GNSS post-processing was performed in RTKLIB (version 2.4.2 p13). Ground- penetrating radar traces and snow depths were geolocated in Matlab R2019a. Liquid water content was calculated in Matlab R2019a using the equation from Roth et al. (1990), "Calibration of time domain reflectometry for water content measurement using a composite dielectric approach". Inputs included snow density, snow depths averaged along 9 m intervals, and two-way travel time from processed ground-penetrating radar averaged along 9 m intervals. QUALITY CONTROL ============================================================================== Ground-penetrating radar and snow depth geolocations Post-processed GNSS coordinates were examined in Matlab R2019a for outlying coordinates, which were removed from the dataset. Raw Ground-penetrating Radar and Snow Depth datasets We used the relative permittivity equation presented in Roth et al. (1990) to compare manually measured snow depths with snow depths calculated from processed ground-penetrating radar. We found that the 73 manually measured snow depths were greater than calculated snow depths by a mean of 14 cm. We recommend this difference be considered when comparing these snow depths with the ground-penetrating radar from this dataset. Liquid Water Content In some cases, liquid water content was calculated as a negative number. If the value was within the uncertainty range, the value was changed to 0 vol. %, Otherwise, the value was changed to NaN (not a number). DATE DATASET WAS LAST MODIFIED ============================================================================== Dataset was compiled in its current format on 2021-08-11. Readme updated on 2021-09-14. RELATED MATERIALS ============================================================================== Bonnell, R.; McGrath, D.; Williams, K.; Webb, R.; Fassnacht, S.R.; Marshall, H.-P. Spatiotemporal Variations in Liquid Water Content in a Seasonal Snowpack: Implications for Radar Remote Sensing. Remote Sens. 2021, 13, 4223. https://doi.org/10.3390/rs13214223 OTHER IMPORTANT INFORMATION ============================================================================== Roth, K., R. Schulin, H. Fluhler, and W. Attinger (1990), Calibration of time domain reflectometry for water content measurement using a composite dielectric approach, Water Resources Research, 26(10), 2267-2273.