Analysis of the influence of ENSO phenomena on wave climate on the central coastal zone of Rio de Janeiro (Brazil)

Abstract

This paper evaluates the influence of the El Niño - Southern Oscillation on the wave climate variability in the central region of Rio de Janeiro's coastal zone. The regional climate of the area was characterized using the WAVEWATCH III wave data model, obtained from NOAA, organized as a 35 year time series (1979-2013). These data were validated for the study area and a characterization and analysis performed by focusing on years with occurrence of strong El Niño/La Niña events. The correlation between the interannual variability of significant wave height and Oceanic Niño Index showed a slight reduction in significant wave height during El Niño years and the opposite pattern during La Niña years, with a lag of four months. This decrease could be attributed to the intensification of the South Atlantic High with a corresponding increase in the occurrence of subtropical jets during periods of El Niño. This weather change causes the blocking of cold fronts in the southern region of Brazil and the consequent reduction in the percentage of waves from the south along the southeast coast.