Measurements of wind-induced loss of solid precipitation: description of a Norwegian field study

Precipitation measurements have a well-documented and mostly wind-dependent bias which is especially apparent during solid precipitation events. The resulting inaccuracy in precipitation data remains an area of concern in quantifying regional and global climate trends. As a high-latitude country, Norway has many solid precipitation events often accompanied by high wind speeds where the current adjustment functions have only limited validity. The presented study aims at improving the quality of solid precipitation data. In a comprehensive field experiment, precipitation data of standard automatic gauges are compared with data of a reference gauge surrounded by a double fence construction to minimize wind impact. Additional meteorological parameters are measured at the test site, allowing for an in-depth analysis of high-temporal-resolution precipitation data. The goal is to develop new adjustment functions for solid precipitation measurements which account for Norway9s typical climate and are suitable for automated measurements. Measurements began in winter 2010/2011 at the alpine test site in southern Norway (chosen after a pre-study in 2009/2010) and will continue for two more winters. In this paper, the test site and its instrumentation are described and preliminary results are presented.