Temporal analysis of precipitation and rain spells in Argentinian centenary reference stations

摘要

Different rainfall parameters are analysed in the present work in order to describe precipitation in three Argentine reference stations. These locations represent their precipitation climate region through a centenary data record. The selected parameters are annual accumulated precipitation, number of days with precipitation and precipitation intensity. All three stations indicate a positive trend in the first two variables over the studied period; moreover, because of a proportional increase, the precipitation intensity parameter has no significant variability. From the analysis of these variables and applying statistical methods, a climatic jump is found in each station, around the 1950s. A second focus of this work is the analysis of rain spells. To this end, a cutoff value for each station is found and used so as to establish the relationship between the accumulated precipitation and the frequency of rain spells per year. The total number of rain spells follows an exponential decay function for their relative frequency, considering the number of days that constitutes them. Rain spell characterisation allows for the understanding of their contribution to precipitation, according with its duration.