Raquel Toste | Searcharxiv

arXiv2025

A multiresolution weather dataset for the Southwestern South Atlantic (2017-2018)

The Southwestern South Atlantic (SWSA) is a key region for climate research and renewable energy assessment, yet high-resolution meteorological data are scarce. We present a multiresolution dataset spanning February 2017--November 2018, combining Weather Research and Forecasting (WRF) simulations with Sentinel-1A/B Synthetic Aperture Radar (SAR) wind fields processed using the CMOD5 model. WRF outputs were generated every 30 minutes for three nested domains (9 km, 3 km, 1 km) through 975 short-term simulations. SAR/CMOD5 wind fields are provided at 500 m and 1 km resolution across 104 acquisition dates. Validation shows strong agreement: daily spatial averages of 10 m wind speed yield RMSE and MAE below 3 m/s on over 93% of acquisition days, while more than 91.5% of pixel-level residuals fall within $\pm$3 m/s. In situ measurements from the Itaja\'{i} buoy further confirmed the reliability of both sources. The dataset supports regional climate studies, wind energy resource assessment, and machine-learning applications in forecasting and downscaling, with usage examples included to aid practical adoption.

physics.ao-ph↗

arXiv2020

Persistent meanders and eddies lead to a quasi-steady Lagrangian transport pattern in a weak western boundary current

The Brazil Current (BC) is a weak western boundary current described as a flow with intense mesoscale activity and relatively low volume transport. We use a 13-year simulation to show that the presence of persistent meanders and eddies leads to characteristic quasi-steady Lagrangian transport patterns, extracted through climatological Lagrangian Coherent Structures (cLCSs). The cLCSs position the surface expression of the BC core along the 2km isobath, in agreement with satellite sea-surface temperature and the model Eulerian mean velocity. The cLCSs deformation pattern responds to zonally persistent cross-shelf SSH transition from positive values near coastline to low values between 200m and 2km and back to positive offshore from the 2km isobath. Zonally-paired cyclonic and anticyclonic structures are embedded in this transition, causing the cLCSs to deform into chevrons. An transport barrier is identified close to the 200m isobath confirmed by limited inshore movement of drogued buoys and indicated by an along slope maxima of climatological strength of attraction (cp). We show that the persistent cyclonic and anticyclonic structures may induce localized cross-shelf transport. Regions of low cp coincide with large shelves and with stagnant synthetic trajectories. We show that cLCSs depict trajectories initiated at the location of Chevron spill (Nov. 2011) as compared to synthetic and satellite trajectories, and the outline of the oil from that accident. There is an agreement between the large-scale oil slicks reaching the Brazilian beaches (Aug. 2019 to Feb. 2020) and the cp at the coast. The identification and quantitative description of cLCSs improves the effectiveness of future emergency response to oil spills, contingency planning, rescue operations, larval and fish connectivity assessment, drifter launch strategies, waste pollutant dispersion and destination.

physics.ao-ph↗