Characterization of wave climate and trends for Alagoas State, NE Brazil

This study presents a spectral wave model developed and validated for the Alagoas State in NE Brazil using satellite altimeter data. The model, spanning 32 years from 1979 to 2010, driven by CFSR wind forcing, captures the wave climate dynamics across seasons and regions. Energetic waves dominate winter and spring, contrasting with milder conditions in summer. Spatially, heightened wave activity is concentrated in the southern border with Sergipe, notably near the São Francisco River mouth, gradually tapering off towards the northern coast. Trends in significant wave height (H_m0) reveal seasonal fluctuations, with winter and spring exhibiting positive trends, while summer trends are predominantly negative. Notably, winter trends peak at 0.6% per year along the central to southern coastal stretch. Conversely, summer witnesses a maximum negative trend of 0.4% per year nearshore. Over the 32-year span, the annual mean shows a general negative trend (∼0.2% per year) across most of the study area, albeit with minor positive trends in the northern region. Particularly noteworthy is the accelerated increase (∼0.4% per year) in extreme conditions (P99) nearshore where H_m0 reached 2.7 m on Maceió coast potentially exacerbating erosion and should be the object of further considerations for coastal management design.