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Minho River intrusion into the Rias Baixas has a twofold impact on estuaries. On the one hand, freshwater intrusion can modify the water exchange with the shelf affecting the residence time. On the other hand, it can fertilize the area and promote phytoplankton blooms and increase estuarine primary production. For these reasons, it is crucial to understand the frequency, duration, and relaxation of river freshwater intrusions. The frequency of intrusion events into the rias was calculated by means of in situ data from 2006 to 2016 using the difference in salinity between the inner part of the estuary and the southern mouth (ΔS) as a proxy. Minho River intrusions, which are characterized by ΔS > 0, were detected in 8.9% of the available measurements in the Ria de Vigo, in 8.4% in the Ria de Pontevedra, and in only 4.5% in the Ria de Arousa. The FLOW module of the Delft3D model, which was previously calibrated and validated for the study area, was used to analyze the hydrodynamics of the intrusion events. The Ria de Vigo, which is the closest one to the Minho Estuary, was chosen to analyze the duration and intensity of the freshwater intrusions. Several consecutive events were detected in early 2010 (January 11th to February 8th) with ΔS values ranging from 0.7 to 2.0. Velocity and density profiles were analyzed in the middle part of the estuary, where seven freshwater intrusions matched the wind peaks favorable to intrusion events with an approximate delay of ~12 h. In general, the duration of the events was on the order of 1.5 days, although in one particular case the event lasted >3 days. The dynamic behavior of the freshwater intrusions was represented using velocity and density profiles along the main axis of Ria de Vigo. Finally, the phases of an intrusion event were characterized: initial positive estuarine circulation pattern; development of the intrusion; well-developed negative estuarine circulation; relaxation of the intrusion and recovery of the initial positive circulation.

The coastal area north of Yucatan has experienced a cooling SST trend from 1982 to 2015 during the upwelling season (May–September) that contrasts with the warming observed at the adjacent ocean area. Different drivers were analyzed to identify the possible causes of that unusual coastal cooling. Changes in coastal upwelling and in sea-atmosphere heat fluxes are not consistent with the observed coastal cooling. The eastward shift of the Yucatan Current observed over the last decades is hypothesized as the most probable cause of coastal cooling. This shift enhances the vertical transport of cold deeper water to the continental shelf from where it is pumped to the surface by upwelling favorable westerly winds.

Sea surface temperature (SST) variability was analyzed for the Bay of Biscay over the period 1982–2014 using data from NOAA 1/4 degree daily OI database. Trends were analyzed on a monthly scale since previous studies suggest that the rate of change was not homogeneous at annual and seasonal scales. The warming calculated for the whole area at the annual scale was 0.26 ± 0.03°C dec − 1 , although the intensity was observed to depend on the month. Higher warming trends were detected from September to November and from April to June with values higher than 0.3°C dec − 1 , whilst lower SST trends were detected from January to March and from July to August with values below 0.2°C dec − 1 . Warming is mainly due to the increase in the duration of the warm season (between 6 and 14 days dec − 1 ) more than the milder winters or warmer summers. This fact is mainly responsible for the increase in the frequency of extreme hot SST days measured in spring (1.16 ± 0.23 days dec − 1 ) and autumn (1.81 ± 0.42 days dec − 1 ). In contrast, trends observed during the warmest month (August), are characterized by an increase (~ 1.0 days dec − 1 ) near shore and a decrease (~ − 1.0 days dec − 1 ) in the oceanic part of the bay.

The turbid plume formed at many river mouths influences the adjacent coastal area because it transports sediments, nutrients, and pollutants.; The effects of the main forcings affecting the Ebro turbid plume were analyzed using data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Aqua and Terra satellites over the period 2003-2011. Composite images were obtained for days under certain river discharge conditions (different flow regimes) and different types of wind (alongshore and cross-shore winds) in order to obtain a representative plume pattern for each situation.; River discharge was the main driver of the Ebro River plume, followed by wind as the secondary force and regional oceanic circulation as the third one. Turbid plume extension increased monotonically with increased river discharge. Under high river discharge conditions (>355 m(3) s(-1)), wind distributed the plume in the dominant wind direction. Seaward winds (mistral) produced the largest extension of the plume (1893 km(2)), whereas southern alongshore winds produced the smallest one (1325 km(2)). Northern alongshore winds induced the highest mean turbid value of the plume, and southern alongshore winds induced the lowest one. Regardless of the wind condition, more than 70% of the plume extension was located south of the river mouth influenced by the regional oceanic circulation.

Thermohaline trends along the water column were analyzed by means of Argo float data in the Bay of Biscay over the period 2004–2013. Water occupying the upper 100 m was considered as Surface Water (SW). Two deeper water masses were considered: Eastern North Atlantic Central Water (ENACW) and Mediterranean Water (MW). SW was observed to salinificate at a rate of 0.006 y− 1, while no significant trend was found for temperature. ENACW was found to warm and salinificate at a rate of 0.012 °C y− 1 and 0.004 y− 1, respectively. MW cooling and freshening was observed at a rate of − 0.011 °C y− 1 and − 0.005 y− 1, respectively. Both temperature and salinity variability were mainly due to intrinsic changes in water masses, except for temperature in the upper part of ENACW, where the vertical uplifting of isopycnals (~ 80 dbar) balances intrinsic changes in this water mass. Comparison with previous research suggests that the observed changes are consistent with those measured along the Western coast of the Iberian Peninsula.

Upwelling events have been analyzed along the western part of the Cantabrian coast from 1967 to 2007. This analysis shows that the highest number of days under upwelling favorable conditions was observed from June to September (12–14 days per month) with a probability of finding consecutive days under upwelling favorable conditions decreasing from 47% to 17% when events between 1 and 5 consecutive days were considered respectively. This situation was also corroborated by Sea Surface Temperature data which revealed the presence of cold water over the continental shelf, near coast, associated with upwelling favorable winds. This cold water was also observed inside the estuaries located in this area. The water temperature signal measured at the inner part of the Ria de O Barqueiro (NW Iberian Peninsula) from June to September 2008 showed to be negatively correlated with the Upwelling Index calculated in front of the northern Galician coast. This correlation tends to increase as the number of lag days between both variables increases. The maximum value of − 0.8 corresponds to a lag of 5 days.

Ekman transport is studied close to the Galician coast by means of wind data provided by the QuikSCAT satellite from November 1999 to October 2005. Three different coastal zones are identified, western coast from Mino River to Cape Finisterre, middle coast from Cape Finisterre to Cape Ortegal and northern coast, from Cape Ortegal to Cape Penas. In addition to existence of long-term variations, the periodicity of the transport signal is characterized by an annual component (365 days), a seasonal fluctuation (50–80 days) and a time scale related to passing storms (15–20 days). Although the periodicity of the signal is similar at the three zones due to external meteorological forcing, the Ekman transport is modulated by the presence of the coast, in such a way that seasonal patterns vary in intensity and direction along the coast. Thus, the spring–summer pattern is characterized by high transport at the western coast, pointing seaward perpendicular to the shore-line. The same orientation is observed at the middle coast although with a lower magnitude. Finally, Ekman transport at the northern coast points landward and oblique to the shore-line. The different transport orientations are shown to be responsible for the upwelling probability variation along the coast. On the other hand, the autumn–winter pattern does not show a clear trend with important inter-annual differences showing the high variability of Ekman transport for this period.

The Atlantic and Cantabrian coasts of the Iberian Peninsula suffer the periodic passage of storms which give rise to severe sea states. Standard generation- propagation models (WAM, WAVEWATCH, SWAN) are commonly used for operational oceanography purposes with satisfactory results both in the open ocean and in near shore areas but they do not provide information about the possibility of flooding in coastal areas. A 2D HV version of SPH (Smoothed Particle Hydrodynamics) model is considered to propagate the signal provided by generation- propagation models to the coast and to analyze the nature of coastal structures overtopping as a tool to create maps of risk. SPH is shown to provide valuable information about overtopping (maximum water height and water velocity) under the stormy conditions suffered by the Galician coast on February 17, 2006.

Wind measurements from SeaWinds scatterometer on the NASA QuikSCAT satellite and wind forecasts from two different operational numerical models provided by MeteoGalicia were compared for a 4-year period (2002–2005) in Galician coast environment. Available wind data buoy measurements were also used to complement the analysis. A statistical analysis based on mean errors, root mean square errors and complex correlation was performed from spatial, temporal and directional points of view. In the spatial comparison no significant differences between models and satellite were observed and the error magnitudes of the models are compatible with typical QuikSCAT errors. The suitability of satellite wind estimations for data assimilation in these models must be further investigated. Negative bias of models with respect to the satellite was also confirmed with buoy data, in such a way that models overestimation is smaller than the satellite one. Big errors in wind direction appear in southeasterly and southwesterly winds for both satellite and models, contributing to high RMSE values when compared to buoy data. These errors were mainly attributed to the effect of insufficient spatial resolution near shore.

A probabilistic particle tracking model is used to simulate the oil dispersion after the Prestige wreckage. This oil spill constitutes a suitable benchmark to analyze the capabilities of a probabilistic model, since the time elapsed from wreckage to oil landing (12 days) is much longer than the reliability time associated with forecast winds, usually on the order of 3–4 days. The particle model can be run in two different modes: real time mode (when existing reliable wind fields for the event under scope) and in probabilistic mode (in absence of reliable wind fields but with historical fields corresponding to a similar period). The validity of the particle model is first evaluated in a hindcast way, running the Prestige case with the wind fields corresponding to the period November 19 to November 30, 2002, which were not available at the moment of the wreckage. Calculations show the accuracy of the model to provide the right impact point and timing. The probabilistic model is then used to simulate the same event by means of historical data. The region where the oil landed is shown to be the area with the highest probability to be impacted.

9 páginas, 8 figuras, The hydrographic behavior of the Galician Rias Baixas is studied under the influence of the Miño River outflow. This study is carried out in spring 1998 under a high Miño River discharge and favorable wind patterns to spread the river plume northward of river mouth, toward the Rias Baixas. This freshwater intrusion reverses the normal salinity gradient in the along axis direction in the rias of Vigo and Pontevedra, but not in their neighbor ria of Arousa., This work was partially supported by CICYT under projects MAR96-1782 and REN2003-04106-C03 and by ‘Xunta de Galicia’ under project PGIDIT02PXJA38301PR