Title --- stossel_box_weights.csv Authors --- Eli Schwat Lead and corresponding author Graduate student 301-651-3959 Civil and Environmental Engineering University of Washington 201 More Hall, Box 352700 Seattle, WA 98195-2700 https://orcid.org/0000-0003-1212-5735 elilouis@uw.edu Daniel Hogan https://orcid.org/0009-0008-0553-6783 dlhogan@uw.edu Civil and Environmental Engineering, University of Washington Jessica Lundquist https://orcid.org/0000-0003-2193-5633 jdlund@uw.edu Civil and Environmental Engineering, University of Washington Ethan Gutmann https://orcid.org/0000-0003-4077-3430 gutmann@ucar.edu National Center for Atmospheric Research: Boulder, CO Julie Vano jvano@agci.org Aspen Global Change Institute Dataset Description --- **Introduction** This dataset contains measurements from 2 "stossel boxes", or manual lysimeters, 4-sided boxes that are filled with snow, placed into the snow such that their surface is flush with the snow surface, and left for some time. The boxes have dimensions 40 x 40 x 20 cm. The weight of the boxes is measured upon being filled and then measured after some period of time. Boxes were generally measured in the morning, after sunrise but before the sun had risen above nearby ridges, and in the evening, before sunset but after the sun had fallen below nearby ridges. The change in weight over daytime is usually negative and represents the mass of snow lost to the atmosphere via sublimation. The change in weight over night time is usually positive or near-zero and represents the mass of snow gained from the atmosphere via deposition/ condensation (also known as surface hoar formation). **Data version number and date** Version 0, 2023-09-18 **Data Status (Preliminary or Final)** Final **Time period covered by the data** 2023-01-31 to 2023-03-02 **Physical location** Latitude/Longitude: 38.958330, -106.989055 Elevation: 2892 meters **Data Frequency** Approximately every 12 hours. Instrument Description --- Two boxes with dimensions 40 x 40 x 20 cm, along with a standard kitchen weighing scale were used to create this dataset. The boxes were made with 9 mm thick white KOMATEX closed-cell, rigid foamed PVC, which has a material density of 550 kg/m3, thermal conductivity of 0.06 W K-1 m-1, and specific heat capacity near 1 J/g-°C. Data Collection and Processing --- Data collection was performed at the Gothic townsite in the East River Valley of Colorado. At the beginning of a new deployment, the two boxes were filled with snow. This was accomplished by digging a pit in the snow with one straight vertical wall, using a standard avalanche safety shovel. Each 4-sided box was pressed into the side of the straight vertical wall, flush with the snow surface, such that the box was completely filled with snow and the natural snow surface of the snow inside the box was preserved. The weight of the snow-filled box was then measured on the scale. After weighing the filled box, a small hole in the approximate shape of the box was dug in a nearby area with undisturbed snow. The box was then placed into the hole such that the surface of the snow in the box was flush with the surrounding natural snow surface. At subsequent measurement times, the box was removed from the hole, weighed, and placed back into the hole. Measurement times were either in the morning (between 07:30 and 08:30 am) or in the evening (between 4:00 and 7:00 pm). After an initial filling of the boxes, the snow was left in the boxes and measurements were repeatedly made each morning and evening until stormy or windy conditions disturbed the snow in the boxes (by snowing on the measurement area or blowing snow away from the measurement area). In some cases, measurement periods lasted 6 days. After stormy or windy conditions, the boxes were emptied, refilled, and a new measurement period begins. Data Format --- The dataset is provided as a comma-delimited text file (csv). Nine columns are included in the file. *deployment_number* - the number deployment. The first measurement of each deployment is when the boxes were filled with new snow. *date_time* - the date and time of the measurement/weighing, in format dd/mm/yyyy HH:MM:SS. *box_1_g* - the measured weight of box 1 filled with snow, including the weight of the box, in grams. *delta_box_1* - the change in measured weight of filled box 1, in grams. A value is only supplied if there was a previous measurement. For measurements made in the morning, a previous measurement was made the night before. For measurements made in the evening, a previous measurement was made the morning of the same day. *delta_box_1 [g/m2]* - the same as *delta_box_1*, normalized by the area of the large face of the box (40 x 40 cm). *box_2_g* - the same as *box_1_g* but for the second box. *delta_box_2* - the same as *delta_box_1* but for the second box. *delta_box_2 [g/m2]* - the same as *delta_box_1 [g/m2]* but for the second box. *comment* - notes indicating weather or snow conditions that may affect the quality of the measurement. Data Remarks --- Data collections from different deployments are combined in the single CSV file. At the beginning of each deployment, the boxes were filled with new snow. The "delta" measurements are not available for the first row of measurements from each deployment, because those weights are measured immediately after refilling the boxes. We recommend only using data points for which the "delta" measurements from box 1 and box 2 are in close agreement. References --- These measurements were inspired by this study: https://doi.org/10.1029/2009WR008198. Appendix --- GCMD science keywords: snow water equivalent, snow, deposition