**1. Introduction**

The diurnal variability is directly related to surface drag such as friction drag, heat flows, mass, and energy [1]; thus, it is the first climatic mode affected by climate change, with possible implications for the occurrence of events in extreme conditions. Studies concerning the diurnal cycle depend on observing data collected in situ, since there are few sets of meteorological data with sub-daily sampling for most continental parts of the globe despite some incipient initiatives (for example, [2]).

Systematic analysis of diurnal cycle can be used for understanding relevant scientific issues in different environmental variables, such as radiation, cloudiness, air and sea surface temperature [3,4], atmospheric activity of rays [5,6], particulate matter, and air pollution in urban areas and forested regions [7,8]. Due to the complexity of the physical processes that modulate the diurnal cycle of precipitation, simulations of this cycle have been used to evaluate the efficiency of climate models [9–11]. In other way, some studies have analyzed the diurnal cycle in a perspective of the difference between present and future climate, identifying changes in the precipitation intensity during 0300 and 1200 UTC worldwide, including South America [12,13].

From January 2008, the National Institute of Meteorology (Instituto Nacional de Meteorologia) (Brasília, Brazil) started to monitor different meteorological variables with one-hour sampling through automatic stations in all continental areas of Brazil. From this perspective, the present research is the broadest analysis of sub-daily precipitation performed with data collected in loco in Brazil. In this sense, the objective is to characterize the space–time aspects of the diurnal cycle of precipitation in Brazil during a continuous

**Citation:** Valentim, A.M.; Santos e Silva, C.M.; Rodrigues, D.T.; de Araújo, P.A.A. Analyses of Maximum Precipitation in Brazil and the Variability of Diurnal Cycle. *Environ. Sci. Proc.* **2023**, *25*, 95. https:// doi.org/10.3390/ECWS-7-14229

Academic Editor: Athanasios Loukas

Published: 16 March 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

period of 13 years. In addition, we demonstrated the regional aspects using multivariate statistical analysis and showing the seasonal variability of the diurnal cycle.

### **2. Materials and Methods**
