Calibrating the data logger…
Accurate precipitation measurements in complex terrain are paramount for mountain meteorology, hydrology, and water resource studies. However, complex topography and high spatio-temporal variability in mountains lead to precipitation measurement biases. These biases depend on how an instrument measures precipitation, where it measures precipitation, and how it responds to the meteorological characteristics of each precipitation event. To better understand how these biases vary across instruments, events, and seasons, we compiled two years of precipitation measurements from 11 gauges deployed during the Surface Atmosphere Integrated Field Laboratory (SAIL); Study of Precipitation, Lower Atmosphere, and Surface for Hydrometeorology (SPLASH); and Sublimation of Snow (SOS) campaigns, supplemented by one radar-derived product and two independent gridded products. We evaluated measurement performance against a well-maintained reference gauge, identified the meteorological and instrument-specific drivers of measurement bias, and determined which gauges were most robust in this harsh environment. We found a large discrepancy in total accumulations across gauges, with individual gauges recording totals that ranged from 56% to 153% of the reference gauge. However, these biases relative to the reference were not distributed uniformly over time. Across all instruments, 40–60% of the total bias was concentrated in only 10 events that occurred primarily during winter. These eventspecific biases disproportionately reflected instrument-and environment-related limitations, with dominant contributors including power issues, gauge burial, blowing snow, and high snowfall rates. For future precipitation measurement studies in mountainous, snow-dominated terrain, we recommend at least two co-located storage-type gauges with low power requirements be deployed to provide reliable, continuous measurements.