Ondas secundárias geradas por interação não-linear entre maré e onda planetária.

Abstract

This study investigated the nonlinear interactions between the ultrafast Kelvin wave and the diurnal tide using meteor radar wind data collected in São João do Cariri-PB (7.4°S; 36.5°W) during the year 2020. The main objective of this study was to investigate the nonlinear interaction between the ultrafast Kelvin wave and the diurnal tide in the high equatorial mesosphere. To achieve this, we focused on identifying and characterizing Kelvin waves and identifying possible secondary waves generated by this interaction. The analytical methodology and tools used for data analysis included a transformed wavelet, Lomb-Scargle periodogram, and statistical methods such as curve fitting, which allowed us to calculate wave parameters and identify frequencies indicative of nonlinear interactions, specifically at 0.75 or 1.25 cycles per day. The analysis of results revealed consistent signals of secondary waves resulting from the nonlinear interaction between the primary waves: tide and Kelvin at various altitudes and periods, particularly within the intervals of days 1-16 and 240-260 of the year. The results highlighted several fundamental aspects: we successfully identified and characterized Kelvin waves, calculated parameters such as phase structures, wavelengths, and amplitudes. Next, we characterized the diurnal tide by calculating its parameters, including wavelength, phase structure, and amplitude. Furthermore, we proceeded with the identification and characterization of secondary waves, calculating their wavelengths and amplitudes. This step was crucial for shedding light on the understanding of nonlinear interactions between primary waves that lead to secondary waves. We observed modulations in tidal amplitude during the same period as the Kelvin wave, an important finding that, although complex, underscores the occurrence of nonlinear interactions. These results demonstrate the significance of refining analysis methods for a deeper understanding of seasonal variations and other factors that impact zonal wind disturbances.