Finally, the graphs that show the spatio-temporal variability of rain with their analysis were made.
The analysis of the events was carried out by grouping different-duration events and identifying the internal characteristics of each. This allowed to understand the internal structure of the rain during events in the city of Manizales. An isolated event of rain was defined as precipitation with a magnitude and duration potentially capable of generating surface runoff and an occurrence continuous in time, without interruptions greater than 15 minutes (interruptions equal or greater than 15 minutes were considered separate events).
The temporal distribution of the rain events was analyzed considering only seven (7) of the thirteen (13) climatological stations of the network because the other stations did not contain information until 2010 (that is, Aranjuez, Emas, La Nubia, Observatory, La Palma, Posgrado and Yarumos), located at strategic points in the city. The available records analyzed were from January 2006 to July 2014, to ensure the homogeneity of the data throughout the study.
Figure 2. (Left ) Events lasting 20 minutes at the Posgrados station during 2006-2014 (Right ) Dimensionless 20-minute event curves for the Posgrados station during 2006-2014
The estimation of the temporal behavior of each station was made with the rain data for each duration of the event, from which a dimensionless graph of rain versus time was obtained for all the events. As an example of the 68 rain events of 20-minute of duration recorded at the station of Posgrados (2006-2014), the accumulated precipitation is shown (see Figure 2, left) and then the same information but dimensionless (see Figure 2, right), which can allow estimating the mean values and the 90th percentile.
The values of the different percentiles were later obtained as well as the averages, such as the one obtained for the station of Posgrados (Figure 3). This same procedure was applied for rains of all durations for all network stations in Manizales.
Figure 3. Percentiles from 5% to 95% for the Posgrados station and rain events lasting 20 minutes