43 documents found, page 1 of 5
Fortnightly variability of the lateral structure of residual flows along non-ro...
Khosravi, Maziar; Fortunato, A. B.; Lopez-Ruiz, A.; Valle-Levinson, A.; Garel, ErwanResidual circulation in estuaries plays a crucial role in controlling salt intrusion, material transport, and ecosystem functioning, making its understanding essential for coastal management worldwide. Despite its importance, the mechanisms driving the transverse structure of residual flows remain insufficiently explored, particularly in relation to the fortnightly tidal variability. This study shows how the ma...
Fortnightly switching of residual flow drivers produced by seawater intrusion i...
Garel, Erwan; Khosravi, Maziar; Valle-Levinson, Arnoldo; Díez-Minguito, ManuelTowed and moored ADCP and salinity measurements were collected in Summer 2023 at two cross-channel transects of the 80-km-long Guadiana Estuary, at 4 km and 20 km from the mouth, during low (< 10 m(3)/s) river discharge conditions. The dataset indicates that the lateral structure of axial residual flows changed from vertically sheared to laterally sheared with tidal forcing. These structures resemble theoretica...
Upwelling processes variability and water circulation along the northern margin...
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 anoma...
Meagre (Argyrosomus regius) move westward with favourable flows along the south...
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 e...
Monitoring invasive macroalgae in southern Portugal: drivers and citizen scienc...
Jiménez, Javier; Simes, Dina; Abecasis, Ana Rita Costa; Relvas, Paulo; Garel, Erwan; Martins, Paula Ventura; Santos, RuiUnder certain environmental and oceanographic conditions, macroalgae can overgrow and accumulate in massive quantities on beaches, causing serious ecological and economic impacts. To address this problem, a citizen science monitoring platform was created to determine the spatial and temporal distribution of macroalgae accumulations along the beaches of Algarve in southern Portugal, with the aim to assess the ex...
A data-driven model to quantify the impact of river discharge on tide-river dyn...
Cai, Huayang; Li, Bo; Garel, Erwan; Pan, Haidong; Zhao, Tongtiegang; Liu, Feng; Ma, Yuting; Ou, SuyingUnderstanding the role of river discharge on tide-river dynamics is of essential importance for sustainable water management (flood control, salt intrusion, and navigation) in estuarine environments. It is well known that river discharge impacts fundamental tide-river dynamics, especially in terms of subtidal (residual water levels) and tidal properties (amplitudes and phases for different tidal constituents). ...
Extension of the general unit hydrograph theory for the spread of salinity in e...
Cai, Huayang; Li, Bo; Gu, Junhao; Zhao, Tongtiegang; Garel, ErwanFrom both practical and theoretical perspectives, it is essential to be able to express observed salinity distributions in terms of simplified theoretical models, which enable qualitative assessments to be made in many problems concerning water resource utilization (such as intake of fresh water) in estuaries. In this study, we propose a general and analytical salt intrusion model inspired by Guo's general unit...
Kinematics of surface currents at the northern margin of the Gulf of Cádiz
De Oliveira Júnior, Luciano; Relvas, Paulo; Garel, ErwanThe subtidal surface water circulation at the northern margin of the Gulf of Cadiz, at the southern extremity of the Iberian upwelling system, is described based on validated hourly high-frequency radar measurements from 2016 to 2020. Statistical analyses (mean, standard deviation, eccentricity and empirical orthogonal functions) are applied to the dataset, which is completed with ADCP time series from multiple...
Mechanisms for longitudinal transport on early life stages in benthic-pelagic f...
Miró, J.M.; Megina, C.; Garel, Erwan; Donázar-Aramendía, I.; Olaya-Ponzone, L.; García-Gómez, J.C.Mechanisms that control the longitudinal transport of larvae and juveniles in nursery grounds such as estuaries are reported for some species. However, the behaviour and population consequences of these mechanisms are still uncertain. In this study, we tested selective tidal-stream transport from the along-channel (up-and down-stream) and cross-channel (from one margin to the other) perspectives for two kinds o...
The structure of incipient coastal counter currents in South Portugal as indica...
De Oliveira Júnior, Luciano; Garel, Erwan; Relvas, PauloThe alongshore subtidal water circulation along the South Portugal inner shelf is characterized by the temporal alternation of equatorward (i.e., broadly eastward) flows related to coastal upwelling processes and poleward (i.e., broadly westward) Coastal Counter Currents (CCCs). The objective of this study is to get insights about the main drivers of CCCs based on kinematic parameters describing the structure o...