Climate fluctuations in relative air humidity and precipitation in brasilia – df

Fluctuations is one of the best known means of climate dynamics, the moment produced by this phenomenon, even within normality, can have significant aspects in human activities. The objective is to ponder the climatic fluctuations in Brasília - DF, focusing on such variations as a means to involve future changes. To carry out this work, data on relative air humidity and monthly and annual rainfall in the period from 1980 to 2012, from the Brasília Meteorological Station - DF belonging to the National Institute of Meteorology, were used. As a result, it can be stated that the relative humidity of the air is decreasing along the studied series, a fact that may be related to the atmospheric fluctuations between so many meteorological elements (temperature, wind, insolation, evaporation, evapotranspiration), causing direct and impact on ecosystems and socioeconomic factors, whose variability results in various impacts, many of them irreversible. Regarding the annual rainfall totals, it is noted that the values are increasing gradually, and this increase may be related to the increase in temperature, which causes greater evaporation and consequently greater precipitation. An anomalous effect of rainfall distribution is observed during the January summers. This climatic factor is known by farmers in the cerrado and cerradão region and in many years is responsible for the fall in agricultural production. The annual total precipitation has been demonstrating a gradual increase in its indices since the 1980s, this increase may be related to the increase in temperature, which causes greater evaporation and consequently greater precipitation. As the relative humidity of the air is proportionally inverse to the temperature, and being a limiting factor for the occurrence of rains with more intensities, it can be clearly seen that since the 1990s a gradual reduction has been occurring in these values. This index may be related to the increase in temperature and consequently to a greater evaporation of water. It should be noted that the relative humidity of the air, in the dry months, has already reached critical levels below 15%, therefore, it can be said that it will influence people's daily lives even more, with aggravation of respiratory problems, drier dry periods and more accentuated, with the possibility of occurrences of fires above normality.