A simple bias-correction procedure to estimate false precipitation due to blowing snow flux into the precipitation gauge

Gauge-measured solid precipitation has systematic errors caused by wind-induced undercatch, wetting loss, evaporation loss, trace precipitation loss and blowing snow. The need to correct these biases has now been more widely acknowledged. In this presentation, bias-correction procedures for gauge-measured solid precipitation in high-wind regions are considered. Using the solid precipitation data with various precipitation gauges installed at Barrow, Alaska, in accordance with the WMO precipitation procedures, the catch ratio of the precipitation gauge to the DFIR (Double Fence Intercomparison Reference) was analyzed on a daily basis. Although the daily catch ratio decreased rapidly with increasing wind speed, the daily catch ratio was considerably scattered under strong wind conditions due to blowing snow. A simple bias-correction procedure physically based on saltation and suspension processes in blowing snow and suitable for high-wind regions is proposed for estimating the amount of false precipitation due to blowing snow flux into the precipitation gauge. It was shown that the scatter of the daily catch ratio under strong wind conditions is correctable and systematic errors are predicted. Further efforts are needed in order to confirm the validity of the bias-correction procedure for false precipitation through field experiments.