Trends of minimum and maximum air temperatures in the state of Minas Gerais, Brazil

Abstract

The objective of this work was to evaluate the trends in minimum and maximum air temperatures in the state of Minas Gerais, Brazil. Data from 43 municipalities were analyzed, considering annual and seasonal scales – January, April, July, and October, which represent the middle months of summer, autumn, winter, and spring, respectively. Historical series of minimum and maximum daily air temperatures, from at least 30 year, were analyzed by the Mann‑Kendall test and linear regressions. Trends were considered significant only if both evaluations were significant; in this case, the rates of temperature shift were determined. There was good agreement between the statistical tests for detecting trends in the historical series, for most municipalities. An increasing temperature trend of up to 1.5oC per decade was observed for minimum temperatures in July, with generalized increasing trends in the greatest part of the state in January and October, and also in the annual scale. Exceptions were verified mainly in municipalities at higher altitudes, in which minimum air temperatures decreased in winter. There is a predominance of municipalities with significant increasing temperature trend, regardless of the evaluation scale. Increasing temperature trends are expected to be more common in the south to north direction, in the state of Minas Gerais.