An evaluation of the Wyoming gauge system for snowfall measurement

The Wyoming snow fence (shield) has been widely used with precipitation gau ges for snowfall measurement at more than 25 locations in Alaska since the late 1970s. This gauge's measurements have been taken as the reference for correcting wind-induced gauge undercatch of snowfall in Alaska. Recently, t his fence (shield) was tested in the World Meteorological Organization Soli d Precipitation Measurement Intercomparison Project at four locations in th e United States of America and Canada for six winter seasons. At the Interc omparison sites an octagonal vertical Double Fence with a Russian Tretyakov gauge or a. Universal Belfort recording gauge was installed and used as th e Intercomparison Reference (DFIR) to provide true snowfall amounts for thi s intercomparison experiment. The intercomparison data collected were compi led at the four sites that represent a variety of climate, terrain, and exp osure. On the basis of these data sets the performance of the Wyoming gauge system for snowfall observations was carefully evaluated against the DFIR and snow cover data. The results show that (1) the mean snow catch efficien cy of the Wyoming gauge compared with the DFIR is about 80-90%, (2) there e xists a close linear relation between the measurements of the two gauge sys tems and this relation may serve as a transfer function to adjust the Wyomi ng gauge records to obtain an estimate of the true snowfall amount, (3) cat ch efficiency of the Wyoming gauge does not change with wind speed and temp erature, and (4) Wyoming gauge measurements are generally compatible to the snowpack water equivalent at selected locations in northern Alaska. These results are important to our effort of determining true snowfall amounts in the high latitudes, and they are also useful for regional hydrologic and c limatic analyses.