Analysis and objective mapping of extreme daily rainfall in Catalonia

What is it about?

The spatial distribution with a high spatial resolution (1km x 1km) of the maximum daily precipitation in Catalonia (Spain), for several established return periods, was obtained. Despite the general concordance between this spatial distribution and the mean annual rainfall spatial distribution in Catalonia, remarkable differences were found in some zones which can be explained by the meteorological scales involved in each case. In Catalonia, the meteorological situations contributing to high rainfall for monthly or annual periods are very different from those producing high daily rainfall. Thus, whereas the synoptic-scale organizations have a greater influence on the annual precipitation distribution, the local and mesoscale factors (e.g., orographical and geographical characteristics, temperature differences between sea and land, distance to sea, and humidity and temperature advections at low levels) have a greater influence on the daily rainfall map.

Featured Image

Photo by Ahmed Hasan on Unsplash

Photo by Ahmed Hasan on Unsplash

Why is it important?

A spatial rainfall analysis from data collected by the meteorological observatories of an area is usually required to assess the maximum daily rainfall (or any other time interval) at any point of a geographic region with an established periodicity. The technique applied was useful to assign a numeric value objectively calculated to every km² of the Catalonian territory, providing a high spatial resolution of the daily rainfall distribution, and notably improving the estimation that can be made from a map analyzed by hand.