A New and Improved Wind Shield for the Measurement of Solid Precipitation

1. Solid precipitation measurements are subject to undercatch caused by wind. Because of this, wind shields are used to help improve the accuracy of solid precipitation measurements. Due the size (12 m in diameter and 3 m tall) and the amount of material, labor, and maintenance required for the Double Fence Intercomparison Reference (DFIR) wind shield, this reference shield is not appropriate for use in operational networks. A smaller version of the DFIR, called the Small DFIR (SDFIR) is used by the US Climate Reference Network (USCRN) at over 100 sites throughout the contiguous US. Unfortunately, like the DFIR, the SDIFR is made of wood, and requires regular maintenance. Due to its size (7.9 m in diameter), the SDFIR is also difficult to install in remote locations. More recently, undercatch was notably reduced with a Belfort double Alter wind shield, which is only 2 m in diameter. The Belfort double Alter shield was designed based on wind break research, with a shield porosity that is much lower than that of the reference shield, the USCRN shield, and the normal double Alter wind shield. Based on these results, a more durable, relatively small (4.9 m in diameter) Low Porosity Double Fence (LPDF) shield has been designed and tested for use in the USCRN. Preliminary results are quite encouraging, with a LPDF-shielded gauge collecting 97% of the winter precipitation accumulated by a SDFIR-shielded gauge at the windiest, snowiest site in the USCRN during 2018-2019.