Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 21, 3525-3542, 2017
https://doi.org/10.5194/hess-21-3525-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
14 Jul 2017
Analysis of single-Alter-shielded and unshielded measurements of mixed and solid precipitation from WMO-SPICE
John Kochendorfer1, Rodica Nitu2,3, Mareile Wolff4, Eva Mekis2, Roy Rasmussen5, Bruce Baker1, Michael E. Earle6, Audrey Reverdin7, Kai Wong2, Craig D. Smith8, Daqing Yang8, Yves-Alain Roulet7, Samuel Buisan9, Timo Laine10, Gyuwon Lee11, Jose Luis C. Aceituno9, Javier Alastrué9, Ketil Isaksen4, Tilden Meyers1, Ragnar Brækkan4, Scott Landolt5, Al Jachcik5, and Antti Poikonen10 1Atmospheric Turbulence and Diffusion Division, ARL, National Oceanic and Atmospheric Administration, Oak Ridge, TN, 37830, USA
2Environment and Climate Change Canada, Toronto, ON, M3H 5T4, Canada
3World Meteorological Organization, Geneva, 1211, Switzerland
4Norwegian Meteorological Institute, Oslo, 0313, Norway
5National Center for Atmospheric Research, Boulder, 80305, USA
6Environment and Climate Change Canada, Dartmouth, Nova Scotia, B2Y 2N6, Canada
7Meteoswiss, Payerne, 1530, Switzerland
8Environment and Climate Change Canada, Saskatoon, SK S7N 3H5, Canada
9Delegación Territorial de AEMET (Spanish National Meteorological Agency) en Aragón, Zaragoza, 50007, Spain
10Finnish Meteorological Institute, Helsinki, 00101, Finland
11Kyungpook National University, Daegu, 41566, Korea
Abstract. Although precipitation has been measured for many centuries, precipitation measurements are still beset with significant inaccuracies. Solid precipitation is particularly difficult to measure accurately, and wintertime precipitation measurement biases between different observing networks or different regions can exceed 100 %. Using precipitation gauge results from the World Meteorological Organization Solid Precipitation Intercomparison Experiment (WMO-SPICE), errors in precipitation measurement caused by gauge uncertainty, spatial variability in precipitation, hydrometeor type, crystal habit, and wind were quantified. The methods used to calculate gauge catch efficiency and correct known biases are described. Adjustments, in the form of transfer functions that describe catch efficiency as a function of air temperature and wind speed, were derived using measurements from eight separate WMO-SPICE sites for both unshielded and single-Alter-shielded precipitation-weighing gauges. For the unshielded gauges, the average undercatch for all eight sites was 0.50 mm h−1 (34 %), and for the single-Alter-shielded gauges it was 0.35 mm h−1 (24 %). After adjustment, the mean bias for both the unshielded and single-Alter measurements was within 0.03 mm h−1 (2 %) of zero. The use of multiple sites to derive such adjustments makes these results unique and more broadly applicable to other sites with various climatic conditions. In addition, errors associated with the use of a single transfer function to correct gauge undercatch at multiple sites were estimated.

Citation: Kochendorfer, J., Nitu, R., Wolff, M., Mekis, E., Rasmussen, R., Baker, B., Earle, M. E., Reverdin, A., Wong, K., Smith, C. D., Yang, D., Roulet, Y.-A., Buisan, S., Laine, T., Lee, G., Aceituno, J. L. C., Alastrué, J., Isaksen, K., Meyers, T., Brækkan, R., Landolt, S., Jachcik, A., and Poikonen, A.: Analysis of single-Alter-shielded and unshielded measurements of mixed and solid precipitation from WMO-SPICE, Hydrol. Earth Syst. Sci., 21, 3525-3542, https://doi.org/10.5194/hess-21-3525-2017, 2017.
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Short summary
Precipitation measurements were combined from eight separate precipitation testbeds to create multi-site transfer functions for the correction of unshielded and single-Alter-shielded precipitation gauge measurements. Site-specific errors and more universally applicable corrections were created from these WMO-SPICE measurements. The importance and magnitude of such wind speed corrections were demonstrated.
Precipitation measurements were combined from eight separate precipitation testbeds to create...
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