Estudo das propriedades meteoceanográfica na borda da plataforma continental de santos

Abstract

Understanding meteorological and oceanographic variations on different time scales in the Santos Basin is essential for predicting and mitigating risks related to weather conditions, supporting maritime defense operations, promoting economic activities like fishing, and oil and gas exploration, and for validating and improving regional climate models. This study examines meteorological and oceanographic variations on diurnal, synoptic, and seasonal scales at the edge of the Santos Continental Shelf (SP). Data from the National Buoy Program's Meteorological Buoy (PNBOIA) were used, subjected to the Quality Control of Real-Time Oceanographic Data (QARTOD) tests. Primarily the following data were analyzed: air temperature (2MAT), sea surface temperature (SST), sea-level atmospheric pressure (SLP), relative humidity (2MRH), specific humidity (2MSH), and wind speed (10MWS). The inverse Fourier transform was employed to decompose the signal of each property into four frequency bands: diurnal (2 h - 24 h), synoptic (1 d - 30 d), intraseasonal (30 d - 90 d), and seasonal (90 d - 365 d). The diurnal cycle of all properties was marked by diurnal frequency, except for SLP which displays a barometric tide with periods of 12 h. SST and 2MAT had a strong Pearson correlation (0.87), with diurnal cycles associated with the variation of solar radiation and Earth's rotation. The amplitudes of SST are smaller than those of 2MAT, probably due to the ocean'shigher heat capacity. The diurnal cycle of RH2M was in the opposite phase to that of 2MAT, with maximum RH2M associated with minimum 2MAT and vice versa. Using bulk formulas from the COARE3.6 algorithms, latent (LH) and sensible (SH) heat fluxes were calculated based on 10MWS and temperature and humidity differences. In the diurnal cycle, the highest losses of LH and SH occurred in late afternoon and early evening, implying higher evaporation and cooling of SST. On the synoptic scale, all variables showed significant variations after the passage of frontal systems, associated with the cold and dry air transported by the post-frontal migratory high. Except for SST and 2MAT, all properties had higher spectral energy at the synoptic scale. Synoptic variations in LH and SH depended both on 10MWS and on humidity and temperature differences between the sea surface and the 2m altitude. Seasonal variations in these heat fluxes mainly depended on the thermodynamic component. Seasonal signals of SST and 2MAT are well represented by a sine wave with a one-year period. 10MWS was the only property with diurnal variance greater than seasonal. Moreover, the data collected by the Santos Meteorological Buoy were compared with reanalysis data, a widely recognized atmospheric database. Data from the European Centre for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5) show a very strong correlation with observed data, suggesting its applicability in the study region. The model also accurately approximated SST values, overestimated 2MAT and SLP, and underestimated 10MWS.