CONCLUSIONS
Rainfall in the urban area of the city of Manizales is quite variable despite being such a small area (35 km2). However, there doesn’t seem to be a relationship with the height of each stations and rainfall.
For all stations, bimodal behavior can be seen in the diurnal cycle and in the monthly cycle, the latter associated with the Intertropical Confluence Zone (ITCZ). In general, it is observed that the stations have monthly averages close to each other, but when their annual value is totaled, variations of up to 70% are observed between the station with the lowest rainfall (La Nubia in the east) and the one with the highest rainfall (El Carmen to the west), indicating a high spatial variability in the city.
As for the diurnal cycle, a decrease in rain is observed between 09:00 h and 11:00 h throughout the city, while the highest rains occur in the afternoon for the eastern zone stations, presumably due to the convective effect of warming during the day. Rains can also be identified in the early hours of the morning particularly in the western part of the city.
The knowledge of the diurnal cycle of rain, of the intra-annual structure of the precipitation and of the rainstorms becomes a planning tool for the territory and a reference input for city builders. For instance, the works in the city of Manizales will be able to schedule their concrete or pavement castings at the most convenient day or month of the year to guarantee construction efficiency. Finally, the knowledge of the diurnal cycle of the rain allows to understand the dynamics of the climate in the Andean region of Colombia, which is strongly influenced by climatic variability.
Regarding the spatial distribution of rainfall, the highest rainfall occurs in El Carmen and Yarumos, the former located to the west while the latter is located to the north-east of the city in a forest reserve. Generally, it rains more to the west of the city, but there are some points of high precipitation in the center (Hospital) and east (Posgrados). Alcázares and Hospital have the highest hourly maximum precipitation values, while the stations with the lowest diurnal maximum precipitation values are La Nubia and Posgrados. Posgrados, Emas, Hospital, Yarumos, La Nubia and Bosques are the stations with the highest relative frequencies, located in the north and center of the city.
The resulting temporal distribution of the rain serves for the designers of hydraulic infrastructures to use design storm more realistically in the city of Manizales, where 20 to 30-minutes rainstorms are prevalent in the city.
Therefore, the dimensionless patterns found serve as a tool for design storms that the different hydraulic infrastructures require in the city of Manizales.
Studies that connect intra-annual, interannual and diurnal cycle variability are recommended, once information is available with a greater number of years (at least 30 years of data). This study is a basis for future researches of this kind.