The modelling of snow cover and its associated feedbacks with the climate system is of particular interest to northern countries like Canada. The Canadian Land Surface Scheme ("CLASS"), which was developed in the early 1990’s for the Canadian General Circulation Model (GCM), and is now being ported to the Canadian Regional Climate Model (RCM) and the operational weather forecast models, was one of the first land surface schemes worldwide to incorporate a realistic treatment of snow cover and frozen soils. Efforts are currently underway to validate and improve the snow sub-model.
Snow surveys have routinely been carried out in Canada for many years, but in most cases the meteorological data required to drive CLASS, and the turbulent flux measurements and other observations required to validate the simulation output, have not been collected concurrently with them. Some datasets have been collected by the university community, and the rescue of these and their use in the validation of CLASS has proceeded for the past four years under the auspices of the Canadian Climate Research Network. Plans are now underway for further collection of data at selected sites. In addition, CLASS participated in the PILPS 2(d) experiment, which is currently being documented in a series of papers. The results of all of this work, and improvements to CLASS which have come out of it, will be presented.