Influence of climate variability over reservoirs volume in the Northeast Brazil
Oceanic indices. Correlation. Rainfall. Reservoirs.
The high variability of rainfall in Northeast Brazil (NEB) can trigger periods of extreme drought, which imply a decrease in the volume of water stored in artificial reservoirs during the rainy season. Thus, in this research, the objective was to identify the relationship between climatic variability and the volume of water in the reservoirs of Northeast Brazil during the period from 1986 to 2018. For this purpose, rainfall data were used, the monthly volume percentage of the total capacity of the reservoirs, oceanic indices, zonal and meridional winds, emerging long wave radiation. Thus, for the aforementioned analyzes, statistical techniques of multivariate data analysis and correlations were used. The results showed that just like the rainfall, the water volumes of the artificial reservoirs inserted in the NEB are also sensitive to the modes of variability of the adjacent oceans. The variability of the main atmospheric systems acting on the NEB is also an important factor regarding the volume of water in the reservoirs. The average of the central position of the ITCZ near the north of the NEB during the months of February to May was approximately -1ºS. However, when this average was not reached, negative rain anomalies were observed, so the average volume of the reservoirs followed this pattern of reduction most of the time. Finally, it is noteworthy that the volume of water in the reservoirs is sensitive both to the indices of the Pacific and Atlantic oceans and to the variability of atmospheric systems that operate where the reservoirs are inserted.