Measurements and modeling of water levels, currents, density and wave climate on a semi-enclosed tidal bay: Cádiz (SW Spain)
Abstract. Estuarine dynamics are highly complex as a result of the temperature and salinity gradients, as well as the multiple interactions between atmospheric, maritime and hydrological forcing agents. Given the environmental and socioeconomic importance of estuaries and their current and future threats due to human interventions and climate change, it is of vital importance to characterize these dynamics, monitor their evolution and quantify the expected impacts derived from climate change. This paper presents a hybrid database combining data obtained in six field surveys (in 2012, 2013 and 2015) and results from a physically-based 3D numerical model for the Bay of Cádiz (southern Spain), a highly anthropized mesotidal estuary. The 3D dataset includes water levels, currents, density and wave climate, allowing for an analysis of bay dynamics at different time scales ranging from intratidal processes to seasonal variabilities. The results offer an example of the potential uses of the dataset and include (1) an assessment of the spatial and seasonal variability of the estuarine dynamics and (2) an analysis of the effects of severe weather events. These examples provide convincing evidence regarding how the dataset can be employed in multiple research fields and applications, including ocean-bay interactions, water exchange between basins, long- and short-wave propagation along creek systems and energy extraction of tidal waves. Therefore, this hybrid dataset may be of significant interest for stakeholders and scientists from different sectors (water engineering, ecology, urban development, energy, etc.) working on the environmental management of the Gulf of Cádiz and other tidally-dominated shallow bays. It can also serve as a benchmark test for numerical hydrodynamic models, infrastructure intervention assessments (e.g., dikes or breakwaters) or renewable energy conversion system models.
Carmen Zarzuelo et al.
Status: open (extended)
- RC1: 'Comment on essd-2022-467', Anonymous Referee #1, 29 Mar 2023 reply
Carmen Zarzuelo et al.
Hydrodynamic data for the Bay of Cádiz (southern Spain) https://doi.org/10.5281/zenodo.7484187
Carmen Zarzuelo et al.
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Review of the article “Measurements and modeling of water levels, currents, density and wave climate on a semi-enclosed tidal bay: Cádiz (SW Spain)”, by Carmen Zarzuelo et al.
In this paper the authors present an oceanographic dataset comprised by observations and numerical model outputs, covering periods of different lengths between 2012 and 2015. Observations are divide into fixed stations measurements and vessel surveys. The stations were equipped with ADCP, CT probes and punctually with a turbidity sensor. The vessel observations consist of CTD profiles, including fluorometer and turbidometer measures, water samples and velocity measures from the vessel-mounted ADP. The simulation is performed by an implementation of the Delft3D model with very high resolution (between 10 and 5 meters), which includes tidal and wave forcing in the boundaries, as well as local river discharge. The model was validated using in situ observations. In addition to the data description, examples of the capacity of the combined dataset to describe processes at different time scales are shown and analyzed.
In my opinion, the dataset presented has a great potential for many different kind of studies in the area, from climatic and ecological analysis to engineering projects, as mentioned by the authors. However, the description of the dataset and the presentation of the application examples given in the paper should be improved before considering its publication in ESSD. Therefore, my recommendation is a major revision at least of the points I list below.
There are two major aspects that need a thorough review. First, the description of the dataset, particularly the observations. In order to understand and use the dataset, potential user should have a detailed description of all the instruments used in the fixed locations and in the vessel. The description given in section 3.1.1 and 3.1.2 is very shallow, and the information summarized in table 1 is insufficient to properly understand the data. You should include, at least, the model and main characteristics of the instruments used, their calibration, accuracy, uncertainty, etc. From table 1, one assumes that different instruments have been used for the different sites and periods, but no information is given about them.
In the post processing section, you don’t give any quantitative description of the data quality. How many measures were discarded? Is the dataset homogeneous?... Also, you mention that the upward looking ADCP measures the whole water column, but how do you deal with the side lobe interference of the instruments? Usually, the samples in the last cell of the ADCP record are strongly affected by spurious signals reflected from the surface. This effect depends on the working frequency of the instrument, which in your case varies among location and time periods. How have you solved this problem?
My second general concern is about the presentation, particularly the figures. Figures should be easily readable, and as self-contained as possible. Most of the figures captions don’t mention all the elements shown in the figures. Color scales and axes are sometimes different from one panel to the another, so comparisons are difficult and some lines and other elements are very difficult to see. A thorough review of all the figures and figure captions is needed. Also, a review of the text is also necessary, there are some words and structures that are incorrect or difficult to understand. When analyzing the examples, even though is not the objective of the paper to analyze them in depth, further explanation of some of the hypothesis made to explain the processes described and some references are missing.
I list bellow some specific points, but a general review of these aspects is necessary.
L7: what do you mean by water levels?
L82: sheltered -> were/are carried out
L85: Give a reference for the values you mention.
Figure 1: The figure and caption should include clearly the model domain, to which period/campaign each site corresponds, what are the model data points. All colors, letters and numbers used should be explained in the caption with no abbreviations.
L133: how do you deal with the side lobe interference when sampling the nearest cell to the surface?
L134: Do you use different instruments? Which ones?
L135: here 1Hz is the sampling frequency not the working frequency, am I right? Mention it please.
L226-228: The model grid, or at least the limits of the domain, should be included in figure 1.
L239-242: This information should be clearer in figure 1.
L250: Which skill score do you use to evaluate the accuracy of the model? You should explain more about this. Potential users need to know on detail how do you evaluate the accuracy of the dataset. Same applies to the observations.
Figure 2. Indicate the skill score used. Acceptance -> agreement/accuracy/correlation.
Figure 3. Here a complete description of the figure is missing. What do you mean by test results? What are the histograms and distributions shown on the axes? This should also be more elaborated in the text (L252-254).
L271-272: fig.2 -> fig. 5
L278: revealed -> resolved?
L282: I don’t see the decrease you mention in the figure.
L282-285: any hypothesis on why you observe this?; fig2d -> fig. 5d
Figure 4. Here again, a more detailed description of the figure is missing. All the variables in the legend should be explained. Gray lines indicate the tide gauge and ADCP failures, meaning that for the rest of the time they were working?
L294-295: This sentence is not clear. Please explain with more detail what you mean.
Figure 5. Significant height wave -> significant wave height.
Figure 6. Please explain all the elements in the figure. What are the vertical white lines (I see they correspond with the profiles below but you should mention it). Please use the same limits for the color bars and the density axes in all the panels. It would be much easier to compare them this way.
L303-304: According to the figure is the opposite. The inner basin is denser in summer and lighter in winter.
L307: for 1, 2, 3 and 4 -> for locations 1, 2, 3 and 4.
L311-315: Former and latter are not correctly used here. Please rephrase.
Figure 8. The font in this figure is too small, very difficult to read. The orange rectangles are also very difficult to distinguish.
L316-319: Please elaborate more and rephrase. It is not clear what you mean. How do you relate the precipitation and radiation variability with the density changes? If you have a hypothesis you should explain it clearly.
L339-340: Please rephrase this sentence.