Analysis of recent climatic variations in Castile and Leon (Spain)

This paper reports the results of the analysis of annual mean temperature and precipitation series front 171 rneteorological stations distributed over Castile and Leon [Castilla y Leon in Spanish] in Spain on monthly, seasonal and annual time-scales for a 37-year study period (1961-1997). Various statistical tools were used to detect and characterize significant changes in these series. The magnitude of the trends was derived front the slopes of the regression lines using the least squares, method, and the statistical significance was determined by means of nonparametric tests. Positive trends of about 0.33 degreesC in the annual mean temperature were found for the whole period. Mean temperatures increased in spring and winter. the winter trend being statistically significant. The months of December and March also showed significant trends. Decreases in rainfall were found for three seasons (winter, spring and autumn), with statistically significant trends in March. Summer precipitation showed slight increases over the 37-year period. On this basis, die authors consider that the increase in summer precipitation and the decrease in the range of average temperatures between the wannest and the coldest months of the year (continentality), point towards a trend to a more oceanic climate in Castile and Leon. (C) 2004 Elsevier B.V. All rights reserved.