August 1, 2013.
One challenge the meteorological community faces is finding an accurate way to measure snowfall, particularly liquid water equivalent (LWE) amounts. This study aims to find a transfer function for measurements from a single Alter-shielded GEONOR with 16-inch laths (referred to as the 16-inch single Alter) as compared to a standard. The standard for snowfall measurement is typically considered to be a GOENOR inside a Double Fence Inter-Comparison Reference shield (referred to as the DFIR). The DFIR is approximately 40 feet in diameter, so the 4-foot diameter single Alter shield is much smaller and more mobile than the DFIR. This study uses data from GEONOR gauges in the single Alter and the DFIR shields at Marshall Field Site (owned by NCAR in Boulder, CO) to determine a transfer function as a function of wind speed that corrects the underestimation from the single Alter. The best transfer function was found from splitting the data-set into two cases: those that had wind speeds less than 5 m/s and those that had wind speeds greater than or equal to 5 m/s. A best-fit line was then found for each of these sets and used to correct the data. When applied to the data for the single Alter GEONOR, the transfer function under-corrected if the event had lower wind speeds and over-corrected if it had higher wind speeds (at lesat 5 m/s).
National Center for Atmospheric Research (NCAR)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0833353. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).