Canadian Forest Service Publications
Evaluation of alternative spatial models of vapour pressure in Canada. 2004. McKenney, D.W.; Hutchinson, M.F.; Papadopol, P.; Price, D.T. Proceedings: 26th Conference on Agricultural and Forest Meteorology. August 23-27, 2004, Vancouver, British Columbia. Natural Resources Canada, Great Lakes Forestry Centre.
Issued by: Great Lakes Forestry Centre
Catalog ID: 29415
CFS Availability: PDF (request by e-mail)
Spatial variation in measurements of atmospheric humidity provide a basis for creating interpolated estimates of humidity variables such as vapour pressure. Here we compare several different thin plate spline models of 1961-90 monthly vapour pressure normals observed at Canadian climate stations including a model where observed vapour pressures were first adjusted to sea-level using standard barometric correction. Using a set of 30 stations withheld from the fitting procedure, we performed independent validations of each model. All models in fact had good signals and would generally be considered as acceptable according to standard diagnostics. In general, withheld data could be predicted with mean errors of less than 10 Pa. The best model was a square root transformation of the vapour pressure field and a trivariate spline with a spatially varying dependence on elevation as determined by the data network. The maps generated as the final products used all data points except for three stations identified as potentially anomalous during the model-building phase.