Bulletin of Forestry Science / Volume 7 / Issue 2 / Pages 99-113
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Investigation of the variation of precipitation

Miklós Manninger

Correspondence

Abstract

The issue of the spatial variation of precipitation can be important in case of using non-locally measured data, while the knowledge about the variation in time is necessary for the interpretation of the predicted changes. At least 100-year-long data series were selected and analysed according to different time window (from monthly over the different water cycle periods to hydrological year). The 30 year reference periods used by climatologists were also taken into account.. From the statistical evaluation the results connected with the variation coefficient (CV) are shown primarily. The author stated that the mean of the shorter periods (1-3 months) is not a good parameter (CV>>30%), while the mean for longer period is more reliable. Generally, the CV of the water cycle periods of the 30-year-reference periods decreases as time goes on. It means that the amount of precipitation hasn’t become more extreme. Even the variation of water cycle periods is so large that ±20% deviation from mean is still in the interquartile range, thus this kind of change in precipitation cannot be named as extreme.

Keywords: precipitation, variation in time and space, variation coefficient (CV), interquartile range