Temporal and spatial distribution of storms on January 24th and 28th, 2020 in Belo Horizonte, Minas Gerais, Brazil

Abstract

The South Atlantic Convergence Zone (SACZ) is the main meteorological system responsible for the occurrence of regular rains in almost the entire central and southeastern region of Brazil in rainy season. During the January 2020 these complex system has generate severe storms especially in Minas Gerais state. These intense episodes of precipitation induced real catastrophes and numerous impacts throughout Metropolitan Region of Belo Horizonte (MRBH) like overflow of water courses and destruction of road systems with closure of major avenues, causing deaths due to flooding or landslide and very high economic losses. The Belo Horizonte City recorded the highest intensity of rain measured in one hundred and twelve years of hydro-meteorological monitoring. The aim of this paper is the analysis of temporal and spatial distribution of rainy 24 and 28 January recorded at 46 automatic weather stations (AWS). These were the worst of all storms recorded at MRBH. In the temporal analysis, were applied the regional IDF relationships, the regional annual frequency curves with dimensionless intensities, and synthetic time-distribution graphs of rainfall or hyetographs. To verify the spatial distribution of these storms some statistical tools from the QGIS software were applied with the isohyets maps drawing. These shown that at the south-central portion of the city high-value isohyets conforms approximately to the high elevations on the windward slope, thus reflecting the prevalent direction of humidity inflow and the role of regional orography in the process of intensifying short-time rains.