The evaluation of the climatic environment of a large area with few reporting stations: a case study of Northern Saskatchewan

Abstract

The evaluation of the climate of a large area with few reporting stations requires a special approach. Northern Saskatchewan, examined in this study, is an example of such an area. The objectives of this study, therefore, are to determine how to evaluate the climatic environment of a large area with few reporting stations and to apply the methods to an analysis of the climate of northern Saskatchewan. A completeness index, developed by the author, was used to measure how satisfactory the climatological records were in terms of length and number of gaps. A correlation analysis, the point distribution coefficient and the spatial pattern of the completeness index were employed for the evaluation of the network of observing stations. Methods for temporal and spatial estimation were applied and the results were tested. It was found that monthly data and normals could be estimated satisfactorily but that daily data could not be as adequately estimated. The results of the spatial estimation were found to be acceptable, although estimated precipitation values were usually less acceptable than estimated temperature values. The improved data base was then used to evaluate the temperature and precipitation climate of northern Saskatchewan. Several intriguing features were disclosed. For example, it was found that stations in the central portion of the study area have January extreme minima that are as much as 6° C. higher than those of the stations of the southern margin of the study area. The frequency of occurrence of mean monthly temperatures proved useful in both temporal and spatial analyses. Cold and warm spells, that is, periods of consecutive days with temperatures below or above certain levels, respectively, were also examined. A noticeable pattern in the distribution of cold spells was found. The distribution shows an abrupt increase in the average number of cold spells per winter north of about 57° North. Other aspects of the climate of northern Saskatchewan such as the frost-free season, growing degree-days, heating degree-days, wind chill and humidex were evaluated, where possible. It was found that wind chill factors at locations in the study area are less than those at Regina, the comparison station in southern Saskatchewan. The length of the frost-free season was found to be just as long in parts of the northern margin as in the southern margin of the study area. Climatic classifications and the continentality of the study area were also examined.