Estevam, M.; Fernandes, A., and Soares, M., 2020. Wavelet analysis applied to the identification of climatic variability in a coastal plain in southeastern Brazil. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1422-1426. Coconut Creek (Florida), ISSN 0749-0208.
Climate change can alter hydrological regimes causing changes in biological communities. The Climatological Water Balance of the Guaratiba region (southeastern Brazil) was calculated for the period from 1985 to 2016. Time series of precipitation, temperature, evapotranspiration, soil water storage (SWS), water excess (WE), water deficit (WD) and water balance (WB) were analyzed through the wavelet transform, to identify the frequencies (cycles) and the temporality of the dominant spectral peaks. The same analysis was performed for some climate (NOAA) indices such as the Multivariate ENSO Index (MEI), Southern Oscillation Index (SOI), and El Niño. Seasonal cycles (1.0-1.3 y) were identified for all parameters, and the MEI, SOI, and El Niño indices. All NOAA indices reveal peaks in cycles of 3.5-3.7 years, as well as precipitation, temperature, and evapotranspiration. The MEI, SOI, and El Nino indices have significant power peaks of 2.4-3 years, as verified for all parameters in the Guaratiba region. MEI and SOI also presented peaks of 5 years, more intense in 1972-1973, 1983-1988, and 1997-1998, but without correspondence with the analyzed parameters. WE, SWS, and WB exhibit peaks in 5.5 years, similarly to El Niño. Water deficit, MEI, and SOI show their highest peaks in cycles of 6.4-6.6 years. Longer cycles were observed for Guaratiba parameters (5-6 and 10-12 y), and NOAA indices: El Niño (10 y); MEI (12 and 47 y); SOI (12, 34 and 42 y) with lower statistical reliability. The present analysis also indicates that all parameters in the Guaratiba region presented intense seasonality. The dominant interannual variability (2.4-2.6 y) was observed for precipitation, SWS, WD, and WB. Cycles of 5.3 to 6.4 y were observed for SWS, WD, WE, and WB. Overall, the cycles identified suggest the influence of ENSO on the Guaratiba coastal plain region.