Assessment of snowfall accumulation underestimation by tipping bucket gauges in the Spanish operational network

Samuel T. Buisán,José Luís Collado,Juan I. López-Moreno,Craig D. Smith,Michael E. Earle,John Kochendorfer,Javier Alastrué,Mareile Wolff

doi:10.5194/amt-10-1079-2017

Abstract

Abstract. Within the framework of the World Meteorological Organization Solid Precipitation Intercomparison Experiment (WMO-SPICE), the Thies tipping bucket precipitation gauge was assessed against the SPICE reference configuration at the Formigal–Sarrios test site located in the Pyrenees mountain range of Spain. The Thies gauge is the most widely used precipitation gauge by the Spanish Meteorological State Agency (AEMET) for the measurement of all precipitation types including snow. It is therefore critical that its performance is characterized. The first objective of this study is to derive transfer functions based on the relationships between catch ratio and wind speed and temperature. Multiple linear regression was applied to 1 and 3 h accumulation periods, confirming that wind is the most dominant environmental variable affecting the gauge catch efficiency, especially during snowfall events. At wind speeds of 1.5 m s−1 the tipping bucket recorded only 70 % of the reference precipitation. At 3 m s−1, the amount of measured precipitation decreased to 50 % of the reference, was even lower for temperatures colder than −2 °C and decreased to 20 % or less for higher wind speeds.The implications of precipitation underestimation for areas in northern Spain are discussed within the context of the present analysis, by applying the transfer function developed at the Formigal–Sarrios and using results from previous studies.

Highlights

Variability of snowfall accumulation strongly influences the ecology and hydrology of mountainous areas and cold regions, impacting economic activities including winter tourism, hydropower generation, floods and water supply for agriculture. (Beniston, 2003; Barnett et al, 2005; Lasanta et al, 2007; Mellander et al, 2007; Jonas et al, 2008a, b; Uhlmann et al, 2009)
These plots are based on 1 min data, instead of on averages over longer periods of time, as considered in the previous World Meteorological Organization (WMO) solid precipitation intercomparison (Goodison et al, 1998)
The differences in snowfall accumulation between the instruments located inside the Double Fence Intercomparison Reference (DFIR) and the UN and tipping bucket (TPB) were less than 20 %, while the difference with the SA was approximately 10 %

Summary

Introduction

Variability of snowfall accumulation strongly influences the ecology and hydrology of mountainous areas and cold regions, impacting economic activities including winter tourism, hydropower generation, floods and water supply for agriculture. (Beniston, 2003; Barnett et al, 2005; Lasanta et al, 2007; Mellander et al, 2007; Jonas et al, 2008a, b; Uhlmann et al, 2009). (Beniston, 2003; Barnett et al, 2005; Lasanta et al, 2007; Mellander et al, 2007; Jonas et al, 2008a, b; Uhlmann et al, 2009). Suitable snowfall warnings based on reliable real-time data must be issued by the National Weather Services because snowfall disrupts transport, increases the number of traffic accidents and injuries and affects the normal function of infrastructures in inhabited areas

Objectives

Methods

Results

Discussion

Conclusion