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Difficulties in obtaining accurate precipitation measurements have limited meaningful hydrologic assessment for over a century due to performance challenges of conventional snowfall and rainfall gauges in windy environments. Here, we compare snowfall observations and bias adjusted snowfall to end-of-winter snow accumulation measurements on the ground for 16 years (1999-2014) and assess the implication of precipitation underestimation on the water balance for a low-gradient tundra wetland near Utqiagvik (formerly Barrow), Alaska (2007-2009). In agreement with other studies, and not accounting for sublimation, conventional snowfall gauges captured 23-56% of end-of-winter snow accumulation. Once snowfall and rainfall are bias adjusted, long-term annual precipitation estimates more than double (from 123 to 274 mm), highlighting the risk of studies using conventional or unadjusted precipitation that dramatically under-represent water balance components. Applying conventional precipitation information to the water balance analysis produced consistent storage deficits (79 to 152 mm) that were all larger than the largest actual deficit (75 mm), which was observed in the unusually low rainfall summer of 2007. Year-to-year variability in adjusted rainfall (33 mm) was larger than evapotranspiration (13 mm). Measured interannual variability in partitioning of snow into runoff (29% in 2008 to 68% in 2009) in years with similar end-of-winter snow accumulation (180 and 164 mm, respectively) highlights the importance of the previous summer's rainfall (25 and 60 mm, respectively) on spring runoff production. Incorrect representation of precipitation can therefore have major implications for Arctic water budget descriptions that in turn can alter estimates of carbon and energy fluxes.

Plain Language Summary Measuring precipitation is difficult in the Arctic because the region is a windy, cold desert. Most rainfall and snowfall occur in amounts that are often too small to be effectively measured, with a majority of the precipitation falling as snow. Measurement gauges perform poorly in this windy environment with undercatch reaching 400 % for solid precipitation (snow), but performing better for liquid precipitation. Still, engineering and research studies that rely on precipitation measurements, rarely account for this underestimation of water received by the landscape. Too low rainfall and snowfall leads to underestimates of both streamflow and water storage in soils and surface water bodies. This, in turn, can lead to erroneous conclusions in regards to permafrost thaw and greenhouse gas emissions, which is partly how the Arctic plays a major role in affecting the global climate. A simple measurement of the maximum snow depth on the ground at the end of the winter, which anyone can do with a ruler, can be an effective solution to reduce the precipitation underestimation problem and its cascading effects on a myriad of other processes.