Gêneses e espacialidades das precipitações nas estações chuvosas de 2010/2011 e 2011/2012 em Belo Horizonte, Minas Gerais, e suas correlações com os impactos hidrológicos

Abstract

The aim of the present work is to identify rain types local spatial patterns of rains at Belo Horizonte MG, from the stagger between the atmospheric geneses in regional scale to the urban spot topoclimatical characteristics, and their influences on the hydrological processes unleashing. Therefore, a city landspace characterization was necessary, which manifests the urban expansion different historic moments, and is water coursers changes, that present themselves as a mosaic of varied typologies that, matched to the occupation forms and natural constraints, determine most liable places to hidrometeorological impacts records, such as Lagoa da Pampulha upstream and downstream, Ribeirão da Onça middle section course, under Av. Cristiano Machado, in Ribeirão Isidoro headwaters, such as Arrudas middle source course, however the lower density occurrence records by area (km²), identified through Kernel technique. These floods and/or inundations records happened between 2010-2011 and 2011-2012 October to April period. Through multivariable statistical analysis, Cluster Analysis application in scores from a Factorial Analysis in Main Components Analusis, 5 rain types groups were identified, which allowed to observe spatial patterns and verify those that characterize each group, both by greater frequency of each type, and by the event identification that determined each spatialization. Group 1 was composed by 20 rains events, all them associated to W/NW/N quadrant winds, in which the South Atlantic Convergence Zone (here by ZCAS) events were the ones that most contributed to the grouping spstialization, where the accumulated were greater in the city middle-southeast portion. Group 2 was composed of 20 events which characterized by the V5 and V6 high values, in other words, rains quite spatially concentrated, which highlighted themselves by the southern variability, in which the greater accumulated happened in the western portion. Group 3, as well as group 2, did little to contribute to the seasonal and monthly accumulated, the 9 events characterized themselves by rains intensities (mm/h) low values, concentrated in the northeast and south portion, Group 4 was characterized by 22 grater intensity events, the spatialities were determined by the events from Cold Fronts, which brought on greater accumulated and greater intensities along Serra do Curral. Group 5 was composed by 5 greatest durability ZCAS events, which brought on the greatest monthly accumulated especially from December and January, with spatial pattern similar to group 1, despite the greater accumulated and great intensities.