Phenomena resulting from night cooling at the Summit Levels of Serra da Mantiqueira in july 2021

Abstract

The climates of mountainous areas in tropical Brazil are poorly understood due to the absence of continuous meteorological observations. This is also the case for Serra Mantiqueira Summit Levels. In order to contribute to this understanding, we chipped in to buy weather stations and install them at the municipality of Delfim Moreira/MG. This work presents some remarkable results of the monitoring already carried out in relation to the variation of the daily minimum and maximum air temperature in July 2021. Two monitoring points are compared with automatic Davis meteorological stations, 1.5km apart, in different relief compartments of the Ribeirão Vermelho valley: the first at the bottom of the valley, at 1711m, the second, at the top of a slope, at 1850m. Regionally, in Serra da Mantiqueira the valley is in a leeward position in relation to the winds that bring humidity in winter (south and southeast). Locally, the study shows the frequency of strong thermal inversions along the topographic profile and also the occurrence of frosts at the valley floor in the analyzed period, related to the action of strong polar anticyclones associated with the South Atlantic Anticyclone. No study has recorded such a frequency of frosts in the Serra da Mantiqueira.