Proposed improvement of the detection and measurements of light precipitation in the Canadian Arctic

Abstract. Snowfall during the extended cold season experienced in Arctic regions is the primary contributor to snowpack evolution, terrestrial components of the water cycle, and many melt-season hydrologic phenomena. Despite this importance, solid precipitation measurements in the Arctic are challenging; frequent periods of light precipitation are often difficult to measure with existing gauge networks, and result in under-estimations of total snowfall during a winter season. This study analyzes the measurement of solid precipitation at the Trail Valley Creek Research Station in the Canadian Northwest Territories, using a weighing precipitation gauge, and micro rain radar. The study period runs from 4 November 2023 to 30 April 2024, with an intensive observation period from 16 March to 2 April 2024, during which detailed manual observations improved our understanding of instrument performance in arctic conditions. The already established weighing gauge was used as the reference for the study and measured a total snowfall (snow water equivalent) during the study period of 68 mm, which increased to 190 mm after corrections for wind and snowfall intensity. Manual observations coupled with radar, however, confirm the difficulty of measuring light precipitation. We present a method of on-site calibration for the reflectivity-snowfall relationship for the micro rain radar, that we use to estimate the low-rate (< 0.2 mm hr^-1) snowfall amounts that are commonly missed by weighing gauges. Adding these trace amounts of precipitation, the total snowfall amount increased by another 24 %. While more work is required to confirm these methods in Arctic environments, this study contributes to a better understanding of current measurement systems and can be used to enhance snowfall estimations.