Comportamento da variabilidade climática nos municípios de Monteiro e São João do Cariri no estado da Paraíba (1980 a 2019)

Abstract

The Region of Cariri paraibano, located in the Brazilian Semiarid region, is characterized by having high variability in precipitation (both spatial and temporal) presenting low rainfall indices and marked water deficit. The population living in this region has as one of the main sources of income the activities related to agriculture, however the success of this activity is linked to climatic conditions. During the dry season, the region suffers losses in the agricultural sector, causing great damage to rural workers/families. In this way, any change in the climate can cause serious impacts for the environment as well as for the resident population. Therefore, the present study aims to analyze and compare climate variability in the municipalities of São João do Cariri and Monteiro, both in the state of Paraíba, on a 40-year time scale (1980-2019). To perform the analyses were: i) verified the existence of a trend in the climatic variables precipitation and temperature; ii) sequential water balance indexes were evaluated year by year, verifying its variability and trend, and iii) the annual climate type (TCA) climate classification was performed. To obtain the results, the daily precipitation and temperature data were used, the first being made available free of charge by the institutions of the National Water Agency - ANA; Water Management Agency of the State of Paraíba - AESA, National Institute of Meteorology - INMET and the School Basin. Regarding the second, they were made available by the institutions of INMET and the School Basin. The results showed that the municipalities, despite being in the same region (pluviometrically homogeneous), have different characteristics. Monteiro has a better water condition in relation to São João do Cariri, however these municipalities have the same behaviors as rainy periods (December to may) and dry (June to November). Regarding the trend test for precipitation and temperature variables, corresponding to the annual analysis of 40 years, it showed that only Monteiro's temperature showed a significant increasing trend. On the other hand, the monthly trend tests for the analyzed period showed that only the months of May, April and July of 1997 contributed to the rupture of the annual temperature of the municipality of Monteiro, since this presented significance, this same condition was not observed for the precipitation variable of Monteiro or for São João do Cariri. Similarly, it is verified for the temperature variable of the last municipality, since they did not present significance. Regarding the results of the Water Balance analyzed by decade, the occurrence of water deficiency was proven for the two municipalities, especially the decades of 1990 and 2010, this analysis of the balance sheet by decade hides the existence of water surpluses, however when the balance sheet was elaborated year by year, it was observed that some surplus months contained, between these months, the most prominent was the month of March, which was the wettest month. Regarding the results of trends in water indices, aridity and humidity, it is verified that Monteiro has more years with better water index conditions, when compared to São João do Cariri. Regarding the aridity tests, these revealed the highest values for the municipality of São João do Cariri. On the other hand, the trend of moisture indices showed that the two municipalities, over the years, mostly have soil moisture below zero. Through the Thornthwaite and Mather Climatic Classification, it was concluded that the two localities inserted in a Semi-arid climate, however, are not all years that present this characteristic, because of the two municipalities analyzed, São João do Cariri presented 68% of the years of the series under analysis within a context of semi-arid climate. In view of the results presented, it is understood that the municipality of São João do Cariri, because it has rainfall conditions with lower rates and high temperature variability in relation to the municipality of Monteiro, will possibly be more vulnerable to the impacts of climate change. The municipality of Monteiro, despite having "better" rainfall conditions, with the advent of climate change, the resident population will also feel the impacts of the climate. Thus, it is suggested that studies of climate variability be expanded to all municipalities of the Cariri Region, since it is understood that the climatic behavior present in the region occurs in a differentiated way (varying in time and space), and, in possession of this knowledge, it will be possible to subsidize the elaboration of public policies in the construction of adaptive strategies of coexistence with climatic extremes.