Estimation of the beginning and end of recurrent events within a climate regime

Exact knowledge of the temporal and spatial variations of the beginning, end and length of a quasi-periodic event can be of importance for estimating climate changes. An extended sequential version of the Mann-Kendall test is presented which makes it possible to describe such events in a statistically significant way and to represent these events in their temporal sequence. The usefulness of this procedure is demonstrated using 2 examples: rainy and dry periods in Northeast Brazil and the annual cycle of relative humidity in Central Europe.