Trends in the annual rainfall and temperatures series in Brazil

ABSTRACT

In recent decades, scientific and academic researchers around the world have been concerned with the assessment of regional and global climate trends. The assessment of changes in the climate system is a planning tool for society as it enables the consideration of possible consequences from the increasing air temperature and changes in precipitation that have been observed around the world. Under the hypothesis of climate change presence in Brazil, the aim of this study was to verify the presence of climate trends in 243 annual data from Brazilian cities of maximum, minimum and average air temperatures and rainfall. The Mann-Kendall (M-K.) and the Pettitt (Pett.) tests were applied in order to evaluate the presence of significant trends. Maps were developed for the spatial visualization of the observed trends. The statistical results show that, from all the studied cities, increasing trends in maximum temperature were observed in 35% of the series, decreasing in 1% and no trends were observed in 64%. For the minimum temperature, increasing trends were observed in 30% of the studied series, decreasing in 8% and no trends in 63%. For the average temperature, increasing trends were observed in 35%, decreasing in 3% and no trends in 62%. For rainfall, increasing trends were observed in 6%, decreasing in 4% and no trends in 91%. The observed trends may be related to the anthropic activities like urban expansion, industrial development and the increasing population density in each studied city.

Keywords:
climatic trends; time series; statistical analysis; environmental changes