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In this paper the relevance of different driving terms that contribute to the winter circulation in the Barcelona Harbor are analyzed. Data from a field campaign are analyzed in order to characterize the most relevant hydrodynamic events. This field campaign covers wind, waves, currents, and water quality parameters under winter conditions (Nov-Dec 2003). These events are related to the velocity response at a control point inside the harbor. Characteristic scenarios are simulated through numerical modeling in order to obtain the corresponding velocity field in the studied domain. The characteristic measured events and the numerical results are compared for velocity and show reasonable agreement under similar conditions. According to these results, the wind- and wave-driven circulations seem to control winter circulation in the Barcelona Harbor. The results obtained increase the knowledge of harbor hydrodynacmics and could be used as a tool to solve certain water quality problems in the Barcelona Harbor. DOh 10.1061/(ASCE)0733-950X(2008) 134:5(275) CE Database subject headings: Harbors; Water quality; Numerical models; Measurement; Spain; Hydrodynamics.

Phytoplankton primary production in coastal bays and estuaries is influenced by multiple physical variables, such as wind, tides, freshwater inputs or light availability. In a short-term perspective these factors may influence the composition of biological variables such as phytoplankton biomass, as well as the amount of nutrients within the waterbody. Observations in Fangar Bay, a small, shallow, stratified and micro-tidal bay in the Ebro Delta (NW Mediterranean Sea), have shown that during wind episodes the biological variables undergo sudden variations in terms of concentration and distribution within the bay. The Regional Ocean Model System (ROMS) coupled with a nitrogen-based nutrient, phytoplankton, zooplankton, and detritus (NPZD) model has been applied to understand this spatio-temporal variability of phytoplankton biomass in Fangar Bay. Idealised simulations prove that during weak wind events (< 6 ms- 1), the stratification is maintained and therefore there is not dynamic connection between surface and bottom layers, penalizing phytoplankton growth in the whole water column. Conversely, during intense wind events (> 10 ms-1) water column mixing occurs, homogenising the concentration of nutrients throughout the column, and increasing phytoplankton biomass in the bottom layers. In addition, shifts in the wind direction generate different phytoplankton biomass distributions within the bay, in accordance with the dispersion of freshwater plumes from existing irrigation canals. Thus, the numerical results prove the influence of the freshwater plume evolution on the phytoplankton biomass distribution, which is consistent with remote sensing observations. The complexity of the wind-driven circulation due to the bathymetric characteristics and the modulation of the stratification implies that the phytoplankton biomass differs depending on the prevailing wind direction, leading to sharp Chl a gradients and complex patterns. [ABSTRACT FROM AUTHOR]

This editorial discusses the impacts of climate change on Mediterranean coastal and transitional areas. The authors emphasize the vulnerability of these regions due to the combination of climate change trends and anthropic pressure. They highlight the importance of assessing recent trends and future evolution of coastal dynamics and climate change impacts in order to develop effective response strategies. The studies collected in this research topic aim to improve knowledge and suggest new paradigms for adaptation actions. The authors also discuss the need for data integration, optimization of investigation efforts, and the development of new criteria and techniques for coastal vulnerability and infrastructure design. They emphasize the importance of engaging regional and local subjects in collaboration with academic research entities to create a knowledge base for coastal resilience building. [Extracted from the article]

The evaluation of the impact of climate change on deltaic systems implies studying a multi-component system in which the complexity of links is high enough to present doing it as a whole. Because of this, it is a reasonable approach to study separately the behaviour of each element, to be afterwards linked into a general conceptual model for deltaic behaviour. Moreover, in the case of largely regulated deltas, the main impacts of climatic change will be marine-related since those related to the catchment areas will be severely damped by river regulation and management policies. This fact implies that coastal fringes may become the main frontier between the delta and climatic change effects. In this context, a methodology to study climatic change impacts on deltaic coastal fringes is here presented. It will be further developed on two companion papers dealing with the study of driving terms and coastal response. As coastal processes act at different time and space scales, determining the 'reference' - initial - situation must be done taking into account the inherent system dynamics. It is thus unrealistic to characterize the initial stage as a static one. In order to avoid this simplistic approach, a comprehensive approach to the coastal system must be employed, with three different scales (long-term/large scale, medium term/scale and episodic).

The evaluation of the impact of climatic change on deltaic coastal systems requires establishing a 'reference situation'. As deltaic coastal zones are highly dynamic areas, it is necessary to define the reference situation as a function of their present evolutive stage. This implies characterizing coastal processes as a complex system defined by the links between driving or forcing terms and the coastal response at different temporal and spatial scales ('long/large', 'medium' and 'episodic' scales). Starting from classical previous works on deltaic systems and including all available field and conceptual knowledge to properly consider present conditions (largely regulated rivers, subsidence, etc.) a detailed methodology to analyse forcing or driving agents at the three mentioned scales is presented. This methodology which developed the general approach presented in a companion paper, will be followed by a future paper focusing on the analysis of the coastal response.