Evaluation of various daily precipitation products for large-scale hydro-climatic applications over Canada
Jefferson S. Wong1, Saman Razavi1, Barrie R. Bonsal2, Howard S. Wheater1, and Zilefac E. Asong11Global Institute for Water Security and School of Environment and Sustainability, University of Saskatchewan, 11 Innovation Blvd, Saskatoon, SK, Canada S7N 3H5 2Environment and Climate Change Canada, 11 Innovation Blvd, Saskatoon, SK, Canada S7N 3H5
Received: 28 Sep 2016 – Accepted for review: 12 Oct 2016 – Discussion started: 13 Oct 2016
Abstract. A number of global and regional gridded climate products based on multiple data sources and models are available that can potentially provide better and more reliable estimates of precipitation for climate and hydrological studies. However, research into the reliability of these products for various regions has been limited and in many cases non-existent. This study identifies several gridded precipitation products over Canada and develops a systematic analysis framework to assess the characteristics of errors associated with the different datasets, using the best available adjusted precipitation-gauge data as a benchmark over the period 1979 to 2012. The framework quantifies the spatial and temporal variability of the errors over 15 terrestrial ecozones in Canada for different seasons at the daily time scale. Results showed that most of the products were relatively skillful in central Canada but tended to underestimate precipitation amounts on the east coast and overestimate on the west. The global product by WATCH Forcing Data ERA-Interim (WFDEI) augmented by Global Precipitation Climatology Centre (GPCC) data (WFDEI [GPCC]) performed best with respect to different metrics. The Canadian Precipitation Analysis (CaPA) product of Meteorological Service of Canada, performed comparably with WFDEI [GPCC], however it only provides data from 2002. All the products performed best in summer, followed by autumn, spring, and winter in order of decreasing quality. Due to the sparse observational network, northern Canada (above 60° N) was most difficult to assess with the majority of products tending to significantly underestimate total precipitation. Results from this study can be used as a guidance for potential users regarding the performance of different precipitation products for a range of geographical regions and time periods.
Wong, J. S., Razavi, S., Bonsal, B. R., Wheater, H. S., and Asong, Z. E.: Evaluation of various daily precipitation products for large-scale hydro-climatic applications over Canada, Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-511, in review, 2016.