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- Relatório setor zonas costeiras e mar: vulnerabilidades atuais e futurasPublication . Moura, Delminda; Garel, Erwan; Martins, Flávio; Mendes, Isabel; Janeiro, João; de Oliveira Júnior, Luciano; Carrasco, A. Rita; Sampath, Ruwan; Costas, Susana; C. Veiga-Pires, C.O litoral algarvio estende-se desde a foz da Ribeira de Odeceixe na Costa Oeste (37° 26’ 38,35’’ N; 008° 48’ 50,00’’ O) à foz do Rio Guadiana na costa Sul (37° 10’ 02,10’’ N; 007° 24’ 07’’ O) num total de cerca de 210 km. Este extenso litoral é constituído por morfologias costeiras muito diversas e talhado em formações com idades e litologias muito variadas. De um modo geral, a costa do Algarve pode ser dividida em i) litoral de arribas rochosas, ii) litoral de arribas arenosas e iii) litoral baixo, que se diferenciam entre si pelo substrato físico que os suporta e pelos processos dinâmicos responsáveis pela sua evolução.
- Upwelling processes variability and water circulation along the northern margin of the Gulf of CadizPublication . de Oliveira Júnior, Luciano; Relvas, Paulo; Garel, ErwanThe present study investigates the contributions of upwelling mechanisms (coastal upwelling from boundary divergence and Ekman pumping from spatially variable wind) at the northern margin of the Gulf of Cadiz (NMGoC) based on high-resolution wind. The effects of the spatiotemporal upwelling mechanisms variability are then explored using current observations along with sea surface temperature and sea level anomaly. Upwelling favourable conditions occur throughout the year along the NMGoC, with the strongest intensity near Cape Sao ˜ Vicente due to a persistent positive wind stress curl. In winter, the surface water divergence is restricted to the coastal boundary due to strong coastal upwelling events that result in a cross-shore sea-level gradient close to the coast. Towards the summer, the gradient increases and extends further offshore (over the slope) at the western region due to the intensification of the Ekman pumping. Therefore, the seasonal and spatial variability of coastal upwelling and Ekman pumping contributes significantly to the offshore position of the geostrophic Gulf of Cadiz Current over the western shelf slope. Furthermore, a permanent sea level depression corresponds to the location of the strongest Ekman pumping, near Cape Sao ˜ Vicente. The dynamic adjustment of this feature may drive the cyclonic cell and alongshore poleward currents often observed in the area.
- Meagre (Argyrosomus regius) move westward with favourable flows along the south coast of PortugalPublication . Garel, Erwan; Winkler, Alexander; Gunasekara, S.S.; Abecasis, David; de Oliveira Júnior, LucianoBased on acoustic detections from a network of five stations along the south coast of Portugal, 25 transits of tagged meagre were identified between 2019 and 2020, mostly in summer. Comparisons with hourly current measurements from a moored Acoustic Doppler current Profiler and an High Frequency Radar system indicate that meagre move westward with favourable alongshore flows at a confidence level > 90% (while eastward transits observations were too few to be significant). Several similar transits of different individuals occurred within two days suggesting a species response to environmental changes. The analysis of surface seawater temperature from ERA5 shows that meagre always swam westward towards colder water, despite their warm water affinities. As such, they reached food-rich upwelling areas when the water temperature was higher than usual (due to the westward advection of warm water), probably optimizing their feeding ability. The demonstrated alongshore meagre movements in response to temperature variations induced by the mesoscale coastal circulation is particularly relevant for the management of this high economic value species in southern Portugal.