Análise temporal do balanço hídrico climatológico e classificação climática de Thornthwaite para Imperatriz - MA

Abstract

The objective of this work was the temporal analysis of the application of the climatological water balance proposed by Thornthwaite and Matter and the application of the climate classification procedure proposed by Thornthwaite for the municipality of Imperatriz - MA. Data from the climatological station in the municipality of Imperatriz were used, comprising daily data on rainfall and compensated average temperature in the period between 01/01/1961 to 12/31/2020. The data were organized in terms of climatological normals with the purpose of representing two distinct periods: 1961 to 1990 and 1991 to 2020. For the analysis of the water balance, the model proposed by Thornthwaite and Matter was adopted and subsequent application of the procedures linked to the Thornthwaite climate classification system. It was observed an increase in the total precipitate between the analyzed periods of 54.9 mm (3.81%) and an increase in the average temperature compensated by 1.2 ºC (4.55%) in the same period. There was an increase in the annual ETP in the period between 1991 and 2020 when compared to the previous period (1961-1990), corroborating an increase of 37.0% in the water deficit in relation to the previous period and a reduction of 9.8% in the water surplus over the same period. The product of the climatic classification by the Thornthwaite method was similar, framing both periods as dry sub-humid climate (C1), megathermic (A’) and with low concentration of ETP in the summer (a’). The divergence occurred in relation to the seasonal adequacy of humidity where in the period from 1961 to 1990 it was classified as w2 (great excess of humidity in the summer) and in the period from 1991 to 2020 it was classified as w (moderate excess of humidity in the summer). This fact indicates a change in the pattern of rainfall distribution over time.