A positive trend in evapotranspiration and soil evaporation ( c . 3 mm/decade) and in runoff (0·6 mm/decade) has been noticed during the vegetation period.
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The sentences
Statistical analysis One of the methods for estimating the existence of a significant trend is the non-parametric Mann–Kendall rank test, based on the values of individual elements of the series and the position of these elements in the series (Mitchell et al . 1966 ).