Construction of a degree-day snow model in the light of the ten iterative steps in model development

Jakeman et al. (2005) discuss minimum standards for model development and reporting and offer an outline of ten iterative steps to be used in model development. They present the main steps and give examples of what each step might include (especially what choices are to be made), without attempting the formidable task of compiling a comprehensive check list of the model-development process. This study reports construction of a simple degree-day snowmelt model in the light of the ten iterative steps. Such a modelling approach has been widely used in operational hydrology, where the motivation is to produce as reliable as possible snowmelt discharge predictions for streamflow forecasting. There were meteorological and snow cover data available from a research site in southern Finland. Measurements included daily precipitation and air temperature records for the period extending from Dec 1, 1996 to Apr 30, 2000, and in the same period snow water equivalent was observed at approximately a weekly interval. These data were used in the development, parameterisation and diagnostic checking of the model in the manner presented in the ten steps.