Coastal Oceanography - Science topic

Dear Prusiti

The issue of flood- or ebb-dominance is closely linked to the morphology and morphodynamics of tidal channels. A good kick-off for understanding this problem is the attached paper by Lanzoni & Seminara (2002; and citations therein), and the chapter by Friedrichs (2010, especially section 3.9 on tidal asymmetry), both also providing the mathematical basis that you request.

Best regards,

Burg Flemming

Hope for u always success

There are several potential reasons, which are hard to distinguish based on what you've written. However, the 'obvious' answer is that sediment transport is ALWAYS a timescale-dependent parameter. The cumulative answer will always be larger the shorter the timescale you are applying it to. This was discussed in some seminal papers like de Vriend et al (1991) and Cowell et al (2003), along with some discussion by Pilkey. For a 'light version' try Gallop et al (2015). It is one of the concepts behind 'morphological' parameters.

Dear Victor

Mostly expressed as items/m3, but you use another unites according to your specified work too!

SPSS IMO is extremely confusing in this area,. Rather than confuse you .more I'll leave that to an SPSS person and mention a simpler solution outside of SPSS, R

If you download jarad Lander R for everyone available in the z-library you will notice that R has a function that reads other data formats directly and simply allows you to use your current table without changing anything.. Examples abound in the Lander book which also explains downloading the R software which is all completely free, and runs on essentially any device including smart phones. Keep your data essentially as is and

switch to R following Lander's advice and move on to a world without such problems all for zero cost. The Lander text has commonly used procedures already set up, eg regression, etc that can be used directly. My advice is look it over and try it. I did and never looked back. Questions can always be asked here and to many other places found by a Google search.. Try it you're going to like it. Best wishes, David Booth

Dear Hossein Jamshidi,

I think, ''Coupled Atmosphere-ocean Mesoscale Model'' would be a batter option in your case. Have a look at the attached article.

Isobaths: To highlight isobaths on a map at 100m, 500m, 1000m, 2000m, 4000m and 5000m: Go to View->Window Properties->Map->Layers, then unclick Automatic selection. You want to plot ‘Ocean Bathymetry’, then click “Compose”, highlight the isobaths (listed above in the “available” tab), then click the “<<” button and tick “draw colourbar” to see the corresponding isobaths on the map

Hi Tariq. It was a suggestion i have given. Hope it works.

Can you explain what are shallow water corrective terms (f4 & f6) ? I study on tides for many years, but I never hear about these terms. If these terms mean oscillations with some specific frequencies, I think you can use S_TIDE which is developed by me (https://www.researchgate.net/project/A-non-stationary-tidal-analysis-toolbox-S-TIDE). Using S_TIDE, you can extract oscillations at any frequencies.

Thank you Chandan.

Delft 3D is a good choice

I used a quadcopter for scanning areas and develop a new map for the area to use it for civil engineering in new projects

Justin -

Could you be using logs to reduce heteroscedasticity?

It sounds like you want to use the overlap in data sets to see how one predicts for the other, and then assume that relationship holds up outside of that set? Hopefully you have reason to think that. If you have enough "overlap" data, perhaps you can see if you get compatible results when you do this for the first half of these "overlap" data, and then for the second half, considering the estimated variances of the prediction errors, or at least the standard errors of the slopes.

At any rate, to consider heteroscedasticity, I would avoid any transformations and use weighted least squares regression, considering heteroscedasticity in the error structure. The first link below provides some examples, and the next is for a tool you can use to do this.

https://www.researchgate.net/publication/333642828_Estimating_the_Coefficient_of_Heteroscedasticity

https://www.researchgate.net/publication/333659087_Tool_for_estimating_coefficient_of_heteroscedasticityxlsx

However, it sounds like you should also look into serial correlation. That isn't an area I can help you with though. I've worked more with finite populations than time series. I suggest you might want to research "generalized least squares" (GLS regression).

Best wishes - Jim

Hey Jorge Arigony-Neto ! Thank you very much!

Best,

G

NDWI index you can use

If you're going to use SWAN I strongly recommended you use Delft3D. It's open-source and has detailed instructions and tutorials. Here's the link https://oss.deltares.nl/web/delft3d.

Thanks Dr. Darren, Dr. Hening and Dr. Guilermo, for suggestions on ADCP, it will be helpful in selection of Appropriate ADCP. Shared ADCP Report is of immense help.

Regards

Rajat

there are many mathematical and model based methods are available for shoreline prediction.

the one of the simple method is given below

Future Shoreline Change = Slope * Time interval + Intercept

Most of the coloured dissolved organic matter (CDOM) occurring in freshwater and estuarine waters has been leached from organic rich soils. Humic substances, which result from the incomplete decomposition of terrestrial plant material, make up the bulk of this CDOM. As CDOM is carried by rivers from land to ocean, a sequence of processes act on these substances. First, flocculation affects a large portion as it crosses the salinity gradient between freshwater and seawater, so that portion is effectively removed as it settles out of the water. Secondly, sunlight is, by definition, absorbed by CDOM and the absorption of certain radiations may lead to photo-degradation into components which are no longer optically active, i.e. no longer coloured. Thirdly, marine microbes may also contribute to CDOM degradation, releasing enzymes that break down the photodegraded components into a form they can absorb. All in all, these processes explain why CDOM is much more abundant in freshwater than in seawater, even though there are also sources of CDOM in the ocean such as biological production.

Hi Fabio

Could be this information help you about Colombia: Ley 1450 de 2011, decreto 1120 del 31 de mayo de 2013: http://www.minambiente.gov.co/index.php/component/content/article/116-ordenamiento-manejo-integrado-costero-y-marino

And this: http://www.invemar.org.co/redcostera1/invemar/docs/458ZonasCosteras.pdf

Best regards.

Totally agreed with Matthew Mabey . It is a regular phenomenon but complicated and a broad field of study. Just let's add a comment about its dynamics. One fundamental feature of polar vortex is its nonlinear evolution of its instability in diabatic and adiabatic environments. The growth of instability and the most unstable mode of a polar vortex in gamma plane can define the crudest features of the vortex. The stationary state of zonal velocity in 'geostrophic balance' can specify the most unstable mode based on the linear stability analysis that is not universal and varies for each planet.

For more information and having a big picture about underlying dynamics of polar vortex and polar jets on Earth and other planets like Mars or Saturn and vortex in general, I propose to read some relevant articles like:

Dear Dariusz,

Many thanks to you indeed for your suport.

Yes. First you have go through work by Saji et al. (1999). The IOD events are characterized by SSTA in the western tropical IO (50E-70E and 10S-10N) and SSTA in the eastern tropical IO (90E-110E and 10S-0N). This anomalous zonal SST gradient occurs in short time interval, generally having peak phase of SST anomalies in SON. For classification of IOD events and its intensity you can use normalized DMI.

As indicater by George de Neef, there is no simple answer, as a proper design depends on a number of aspects:soil properties, cage characteristics and environmental conditions and economic design life of the cage and the risk percent to encounter higher loadings. I put below a list of relevant publications, I used in a recent advisory study. Happy industrious learning.

References:

Ágústsson G., 2004. Design considerations and loads on open ocean fish cages south of Iceland, M.Sc. thesis, University of Iceland, June 2004

Aarsnes J. V., H. Rudi and G. LoLand, 1990. Current forces on cage, net deflection, Engineering for offshore fish farming. Thomas Telford, London, 1990

Berstad, A.J.and Heimstad, L.F.(2015), “Numerical Formulation of Sea Loads to Impermeable Nets”, VI International Conference on Computational Methods in Marine Engineering MARINE 2015, Rome Italy

Berstad, A.J., Heimstad, L.F. and Walaunet, J.(2014) “Model Testing of Fish Farms for Validation of Analysis Programs.” Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Artic Engineering OMAE2014, (June 8-13 2014), San Francisco, California. OMAE2014-2464

Berstad, A.J., Walaunet, J. and Heimstad, L.F (2012), “Loads from Currents and Waves on Net Structures.”Proceedings of the ASME 2012 31st International Conference on Ocean, Offshore and Artic Engineering OMAE2012, (July 1-6, 2012), Rio de Janeiro, Brazil. OMAE2012-83757.

Berstad, A. J., Tronstad, H., Ytterland, A. (2004), “Design Rules for Marine Fish Farms in Norway.

Calculation of the Structural Response of such Flexible Structures to Verify Structural Integrity.” Proceedings of OMAE2004 23rd International Conference on Offshore Mechanics and Arctic Engineering June 2004, Vancouver, Canada. OMAE2004-51577

Berstad, A. J. and H. Tronstad (2005a), “Response from current and regular/irregular waves on a typical polyethylene fish farm” , Maritime Transportation and Exploitation of Ocean and Coastal Resources. Eds. C. Guedes Soares, Y. Garbatov, N. Fonseca. 2005 Taylor & Francis Group London. ISBN #: 0 415 39036 2.

Bessonneau J.S., Marichal D. 1998. Study of the dynamics of submerged supple nets (application to trawls), Ocean Engineering, 25(1), pp 563-583

Beveridge M. C. M., 2004. Cage Aquaculture, 3rd Ed., 2004 by Blackwell Publishing Ltd

Beveridge, M.C.M.B. 1996. Cage aquaculture, 2nd Edn. Fishing News Books, Oxford, p. 346.

Blendermann W., 1987 .An analysis of the hydrodynamic forces on cables and nets, Applied Ocean Research, 1987, Vol. 9, No. 4

Bratteland E., ed., 1988. Advances in Berthing and Mooring of Ships and Offshore Structures, Kluwer Academic Publishers.

Burrows R., R.G. Tickell, D. Hames & G. Najafian, 1997. Morison wave force coefficients for application to random seas, Applied Ocean Research, 19 (1997) 183-199, Elsevier Science.

Cairns, J. and Linfoot, B.T. 1990. Some considerations in the structural engineering of sea cages for offshore fish farming. In: - Acquaculture Engineering, Technologies for the future, Thomas Telford, London, pp. 63-77.

Carson, R.M. 1988. Engineering analysis and design of cage systems for exposed locations, in: Aquaculture Engineering:Technologies for the Future. Ing. Chem. Eng. Symposium series No. 111, pp. 77-96, EFCE Publication Series No. 66, Institution of Chemical Engineers, Rugby, UK.

Chalia s., 2014. A Numerical Simulation of Full 3D Model of Net-Cage Structure - Mooring Line Tension, International Journal of Current Engineering and Technology, Vol. 4, No. 4 (Aug 2014), http://inpressco.com/category/ijcet

Chen H., and Christensen E.D., 2015. Methods for current and wave interaction with fish cages: A

review. In Christensen, E. D., Sumer, B. M., Schouten, J-J., Kirca, Ö., Petersen, O., Jensen, B., ...

Burchard, H. (2015). D5.3 Interaction between currents, wave, structure and subsoil., MERMAID mermaidproject.eu, FP7 Theme [OCEAN.2011-1] “Innovative Multi-purpose off-shore platforms: planning, design and operation”

Cheslav B., B. Colbourne, N. Bose, W. Raman, 2009. Aquaculture Net Drag Force and Added Mass, Aquacultural Engineering 41, pp. 14–21.

Cifuentes C. and M. H. Kim, 2014. Dynamic Analysis for the Global Performance of An SPMFeeder-Cage System Under Waves and Currents, China Ocean Eng., Vol. 29, No. 3, pp. 415 – 430

Cremer M. C., H. P. Lan, and J. Chappell, 2008. Engineering Manual: U.S. Soybean Industry OCAT Offshore Ocean Fish Culture Cage, U.S. Soybean Export Council

Dept. of Agriculture, Food and the Marine, 2016. Protocol for Structural Design of Marine Finfish Farms, April 2016, Ireland

Gansel L. C., D. R. Plew, P. C. Endresen, A. I. Olsen, E. Misimi, J. Guenther, Ø. Jensen, 2015.

Drag of Clean and Fouled Net Panels – Measurements and Parameterization of Fouling, PLOS ONE

10(7):e0131051. doi:10.1371/journal.pone.0131051

Huguenin J. E., 1997. The design, operations and economics of cage culture systems, Aquacultural Engineering I6 (1997) 167-203

ISO 16488:2015, 2015. Marine finfish farms - Open net cage - Design and operation, International Standards Organization, 15 July 2015.

Kumar V., and Karnatak G., 2014. Engineering consideration for cage aquaculture, IOSR Journal of Engineering, Vol. 04, Issue 06 (June. 2014), V6 pp. 11-18.

Marine Scotland, 2015. A Technical Standard for Scottish Finfish Aquaculture, The Scottish Government, June 2015, Edinburgh

Mochet C., F. Paquereau, N. Decultot, 2014. Mooring Integrity: Forensics Programs on Used Mooring Connectors Lessons Learned, Present Practices & Future Developments, Deep Offshore Technology International Conference, Aberdeen, Scotland, October 2014., Paper DOT-2014-79

Norwegian Standard NS 9415.E:2009, 2009. Marine fish farms - Requirements for site survey, risk analyses, design, dimensioning, production, installation and operation, Norwegian Ministry of Fisheries

and Coastal Affairs, 10 Nov. 2009, published April 2010, Standards Norway

Rudi H., J.V. Aarsnes, and L.A. Dahle, 1988. Environmental forces on a floating cage system, mooring considerations. In: Aquaculture Engineering: Technologies for the Future. Ing. Chem. Eng. Symposium series No. 111, pp. 97-122, EFCE, Publication Series No. 66, Institution of Chemical

Engineers, Rugby, UK.

Sarpkaya T., and Isaacson M., 1980, Mechanics of wave forces on offshore structures, Van Nostrand Reinhold Co., N.Y., USA.

Siddiqui M. A., V. Nagarajan, 2016. Dynamics of a Single Point Mooring Marine Aquaculture Cage as a Simple Vibrating System, Intl. Journal of Maritime Technology,Vol.5, Winter 2016 (13-25)

Turner R., 2000. Offshore mariculture: Mooring system design, in: Muir J., Basurco B.,- Eds., Mediterranean offshore mariculture. Zaragoza: CIHEAM, 2000. p. 159-172 (Options Méditerranéennes: Série B. Etudes et Recherches; n.30

Zhao Y., T. Xu, C. Bi, G. Dong and S. Liu., 2012. The Numerical Simulation of Hydrodynamics of Fishing Net Cage, in: Zheng Jinhai, ed., Hydrodynamics - Theory and Model, Chapter 12, InTech, March 2012, http://www.intechopen.com/books/hydrodynamics-theory-and-model

Maybe, this book can help you, "FUNDAMENTALS OF FLUVIAL GEOMORPHOLOGY" Ro Charlton.

Respected Dr.C.T.Schafer,

Thank you for your valuable information .

Sincerely,

Thamizharasan

Thanks Guillermo. Yes, I do have wind data and estimated the Ekman upwelling strength, which I think is acceptable (5-10 m/day).  The problem is that I don't have the evidence for the local wind effect on upwelling to accept the theoretically calculated Ekman upwelling strength. Hence, I am searching for a sound reason to include only a fraction of that upwelling in a model.  The current meter data comes in hourly time resolution but I low pass filter them to get rid of tidal components.  I am in a coastal region (southern Vancouver Island) and yes there are wind speed and direction gradients  along the west coast of North America with less upwelling favorable winds near my region. It appears now the poor correlation between current (from depths shallower than mine) and local wind in my study region has been documented in another work . I know some upwelling regions where observed water properties were satisfactorily explained without Ekman upwelling (Best example is a paper by Allen J Clarke, http://onlinelibrary.wiley.com/doi/10.1029/JC084iC07p03743/abstract).  When it comes to my region, the issue of whether Ekman upwelling is negligible is not settled. Therefore, including at least a fraction of it in a model is what I am convinced to do.

ps. I use reanalysis wind with 32 km grid spacing and wind location is not a problem. Some grid points are right next to the mooring.

If you are processing moving-vessel ADCP data, here is the most robust method ---Velocity Mapping Toolbox, developed for ADCP.

You can find more information in this paper, and you could download it from the  USGS Hydroacoustics Web pages.

Regards,

Hao

Hey Fang, Did any report or paper ever come from the study on marine microbial metabolism? May I ask you who you were working with? Would love to hear more about your results as I am looking to start some microbial sampling in the bay myself. Thanks!  

For a world-scale bathymetry grid, the ETOPO1 maps of NOAA can be found here https://maps.ngdc.noaa.gov/viewers/wcs-client/.

For more detailed bathymetry of ocean areas surrounding europe check EMODnet databases: http://www.emodnet-bathymetry.eu/

Data can be obtained in an xyz ASCII format (three columns of x-cordinates (lon), y-cordinates (lat) and z (elevation), or in NetCDF which can be converted to ASCII.

Also naval maps of navionics can be traced for bathymetry in a certain area, http://webapp.navionics.com/?lang=en. Of course local sources are the best choice as the other user suggested.

 Hi Anatoly,

Yes! Your emails were most helpful, so glad we connected. I will continue to follow your research here on ResearchGate.

Jenell

For SST, try https://podaac.jpl.nasa.gov and use "Dataset Discovery" by parameter. You might find the L4 products useful, for example https://podaac.jpl.nasa.gov/dataset/MUR-JPL-L4-GLOB-v4.1. This is a blended product (observations + model to fill in gaps in the satellite observations - beware near the coast during cloudy conditions when only the model is available! you should compare to in situ data for your area if possible).

I think your interest to examine these temperature and salinity density/stability ratio on the coastline rather on the open water. If so, I suggest you look in other factors i.e., tidal chandes, local current circulation and bathymetry. 

These elements are affected local dwillers in many ways i.e., induce spawning

Thanks for you interest sir. Currently working with near shore modelling system. We are using MIKE software to simulate currents, waves, etc...

Sorry for the inconvenient....

Thank you sir 

There are several, if you do not need real time data probably the easier is ECMWF ERA-interim or reanalysis. You need to register but is free.

Thanks Danial..This was really useful for me.

Dear G.Caniaux,

Thank you so much for the references.

Best Regards,

Dear Mohamadreza

Design and construction of MED desalination plant is available in Iran. Several MED plants have been set up by Fanniroo Co. in south of Iran. As I know, MED is more efficient than MSF. So, I think MED is a better choice.

However, thermal desalination is more expensive than membrane desalination. So that transfer of electric power for RO system may be cheaper than installation and operation of thermal desalination.

Moreover, open intake is a common method to provide required feed to thermal desalination plants.

Regards

 Thanks Norman, I will follow that up. I am working in that same estuary myself!

You can use Mike 2016 and Cormix software.

I agree that this is not made clear in the Chen and Millero (1986) paper as they refer simply to "temperature".

My understanding is that Equation 1 allows you to compute the in situ density of a water parcel, Rho^P as a function of its in situ temperature (t), salinity (S) and pressure (P).

Should you wish to compute the potential density, Rho_Theta, which is the density this water parcel would have if it were raised adiabatically to the sea surface, then you need to plug in the potential temperature, Theta, into the One Atmosphere Equation of State given in Equation 2: Rho_Theta = Rho^P(Theta, S)

Theta itself can be calculated from t, S and P using a potential temperature calculator freely available online.

Hi Nadia there is a website that contains tidal gauges hourly datasets of 5 local stations in northern part of IRAN (ANZALI / CHALUS / AMOL / BABOLSAR and BEHSHAHR stations ) considering the website is IRNIAN and due to linguistic difficulties I can help you with downloading the data if it is needed.the address link is as follows :

also check : http://subsite.caspinfo.net/caspinfo/edmed.jsp

Follow this link,

choose ETOPO Global Relief Model (1', 2', 5', Indian Ocean modified), select your region, extract it as nc file and plot it for necessary depths or required scale.

For the residual current speed, you need to take out the tides and analyze the sub-tidal velocities. sub-tidal velocities can be obtained by low-pass filtering your original raw time series. You can also use Tidal harmonic analysis packages like t_tide  to find the tidal velocities and remove it.

You have been indeed helpful. Thanks a lot.

Hello David,

Please get in touch with Joseph M Maina of the University of Queensland. That is his expertise, you can visit his researchgate profile at  https://www.researchgate.net/profile/Joseph_Maina8 and also his google page for his publications at https://scholar.google.com/citations?user=Go7V_2AAAAAJ&hl=en

I am also appending one of his recent publications on a study on coral reefs in Madagascar.

Goodluck,

Beckline.

Global database of dams (but I´m not sure that it includes small dams):

UNEP GEOdata from United Nations Environment Programme:

Dear Sergey,

We work on long-term wind and wave parameters in the Black Sea. Our first work was focused SWAN model setting to the BS (please see http://www.sciencedirect.com/science/article/pii/S0278434312002671). Afterwards, we compared effect of six different wind inputs to the SWAN model performance (please see http://www.sciencedirect.com/science/article/pii/S0141118715001121). Besides, we produced a paper on "Long-term variations of wind and wave conditions

in the coastal regions of the Black Sea" (please see http://link.springer.com/article/10.1007/s11069-016-2407-9). Our recent two works are related to "Wind and wave characteristics in the Black Sea based on the SWAN wave model forced with the CFSR winds" and "Long-term analysis of wave power potential based on 31-year SWAN simulations in the Black Sea". These two works are under review in OE. These last three works are based on the calibrated SWAN model with the CFSR winds for the BS.

Finally, we have a 31-year wind and wave dataset over the BS. In the future, we will focus on some topics (for example storm characterization and trends etc.) using this dataset. Therefore, I do not share the all dataset. But we can produce 31-year time series for some locations which you need.

Best regards

Adem

Hi Mada, you need to post some photos of the different types of microscleres present in the sponge to get an ID

Hello,

I'm doing a similar application with heat model 5 (ocean) with varying meteo parameters. Can you tell me which parameters did you put in the .tem file?

Thank you!

Magda

Thanks for your reply Guillermo Auad, Ronald Kessel and Hugh Lachlan Kennedy.

Upwelling, such as that typical in eastern boundary current regions (California Current, Peru-Chile Current, Benguela Current), brings relatively cooler water to the surface. This creates cool, moist air over the ocean surface. If this air moves over the relatively warmer land mass, the moisture condenses and creates fog.

There is a natural onshore flow that develops in response to the warm thermal low that typically sets up over the land mass adjacent to the eastern boundary, such as in the SW US. This pattern draws cooler marine air over the land, resulting in a persistent foggy condition during the local summer (high upwelling and warm continent). Local vegetation can adapted to this condition, and agriculture interests take advantage of it.

One interesting area of study is how anthropogenic warming will affect this pattern. The hypothesis is that global warming will lead to a warmer continent AND greater upwelling-favorable winds, which may result in greater fog. I am not aware of any substantive study to confirm this. One problem with looking at historical records of fog and SST is that other factors contribute to fog in coastal regions, and the fog is spatially very heterogeneous and localized.

Usually, 2D models are used for oceanographic and beach variations because of the large plan area. Maybe Flow3D is useable for variation in small areas!!

Dear Polgar,

Have you checked the NOAA websites on Tides and Currents?  

There are regional tidal datums as well....

I am not sure if this will help.

Ciao

The 'Pactical Salinity Scale' (PSS) was defined in 1978 and later promulgated by the UNESCO/ICES/SCOR/IAPSO Joint Panel on Oceanographic Tables and Standards in Sidney, BC, Canada, 1-5 September 1980. Because it makes no sense to say the salinity is , for example, 35 PSS, the term PSU was introduced, as the scale is composed of units. However, the use of PSU is discouraged and, because salinity is by definition a dimensionless parameter, it should simply be represented by a number. As practical salinity has been given the symbol S (cf. Unesco Technical Papers in Marine Science 45, 1985, or IAPSO Publication Scientifique No. 32, 1985), one should speak of a salinity of, for example, S = 35.

Burg Flemming

Hi, you might also find the following reference of interest:

Valle-Levinson, A. 2012. Impact of record flooding of a subtropical river on estuary/ocean exchange. Ocean Dynamics 62: 77-85.

According the National Centers for Environmental Information (NCEI, formerly the National Geophysical Data Center) Global Historical Tsunami Database there have been 13 tsunami events observed in the South Atlantic. These events range from the 1755 Lisbon Portugal tsunami that was observed at Tamandare Brazil (8.7 S)  to the 2013 Scotia Sea earthquake and tsunami that was observed on Antarctica. For the complete list with references please access the search pages (select runups in the Southwest or Southeast Altnatic) linked to from the following URL:  http://www.ngdc.noaa.gov/hazard/tsu_db.shtml

How about ETOPO1(https://www.ngdc.noaa.gov/mgg/global/global.html)? This data is free, although resolution is half of GEBCO. You can easily plot image using GMT and this data.

Antonios,

Please have some refs. attached; perhaps general but maybe they will help.

Best regards,

Greg

Dear Pan.

In addition to Xbeach, there are several models including SBeach (Storm induced BEAch CHange Model), the BMAP (Beach Morphology Analysis Package) or other part of the BFM (Beach Fill Module) package developed by Waterways Experiment Station of US Army Corps of Engineers.

Depending on what you want to do, the data availability and where they want to apply can use one or the other.

Best Wishes,

Ridel Rodriguez

I suspect it is. Other mechanism could be the frontal trapping of buoyant coastal current (Chapman and Lentz, 1994).

Do not forgot that you have to consider wave height close and along to the shoreline Consequently wave height at the breaking point is probably the best indicator. You may use a numerical model or empirical rules from Goda and others  (see en SPM, 1984)

I can think of two ways, (1) if you rerun the simulation, output DISSURF or QB (breaking fraction), and where both of those are non zero, waves are breaking. (2) if you can't rerun it, find which breaking method the model is using and apply that constraint to your data, for example the constant fraction method Hb=gamma*h. You could easily figure out where breaking is occuring.

Dear Balasubramanian

The HydroC™ CO2 sensor is a unique underwater carbon dioxide sensor for in-situ and online measurements of dissolved CO2.

karbassi

Having 'integral' properties of the wave field, as Hs & Tz it is IMPOSSIBLE to make a separation; a sum of say two contributions , far & local fields. The reason is that the 'Significant Wave' and 'wave period' are  properties derived from the wave spectra in ALL its contributions (if you only know the sum, it is just out of the question to separate 'contributions'). Only if you have the time series from which such integral properties were estimated, then it is (if the local and far fields have 'non-overlaping' spectra) plausible a separation.....via computing spectra & figuring out which peaks /bands to add as separate contributions.

You can find a lot of stuff in this book, where shoreline extraction from satellite images has been discussed:

With a webcam, we extracted the shoreline from 3 images a day during 5 following days of sea calm and averraging them. In this way we had montly position of the shoreline (paper available).

For me shoreline is the zero ibobath, no trash line, vegetation line, dune foot, etc. Not different from the e.g. 100 m contour in a mountain. For us water doesn't exist when surveying!

I'm interested in collaborating on this topic, if you like.

Cheers,

Enzo

using  the published methods of chlorophyll determination , such as the method of Holden(1965), the results are given in mg per liter. It is very simple to convert these values as follows:mg per cubic meter =0.001mg per liter.

Hi Nitish,

Chlorophyll a in coastal waters is verry variable in time (and often from day to day , or tide to tide). Your sampling interval is, in my own opinion, rather limited. For instance, in my case for a small estuary for one year sampling during ice-free months, the minimum sampling protocol was 7 sampling stations, sampled bi-weekly, in triplicatas, for 7 months and we size fractionned as well.

Basically I think one season each year is probably not sufficiant to have good statistical confidence in the data.

Regards,

Remi

As you probably know, some vegetation (like posidonia) has a very high acoustic echo due to biological activity that causes fine bubbles to build up on the vegetation.

The distribution of such vegetation can be mapped on the seafloor using high-frequency sidescan sonar.  I found some examples of Posidonia in sidescan sonar imagery on this web page:

You may have to do some spot checks (send a diver down, or ROV with lights and camera) in order to confirm that what you think is vegetation in the sonar image is in fact vegetation.

Sonar will not "see" vegetation that has very low acoustic reflectivity (acoustically invisible), of which there may be many kinds. But that vegetation will not interfere with bathymetry measurements.

Note that there are products for seabed classification, designed to operate with all of the main bathymetric sonars and echo sounders (I believe). These analyze the sonar's echo off the seafloor in order to classify the kind of material present on the seafloor, in real time. Such products could presumably be trained to detect, classify, and map the distribution acoustically reflective vegetation.

See for instance the QTC Seabed classification software:

Such products are designed to discriminate mud from sand, from clay, from silt, etc., but they should be able to classify seafloor vegetation too, especially posidonia,  You have to speak with the manufacturer.

For acoustically reflective vegetation, then, you might at least map its distribution (sidescan sonar) or detect its presence in bathymetric sonar (seabed classifier), in order to identify where vegetation may be interfering with bathymetric measurements. Correcting against their interference is more difficult.  

Water quality refers specifically to the water column (e.g. dissolved oxygen, turbidity, nutrients, toxics).  Environmental quality in the marine environment could refer to a broader range of metrics including sediment quality (e.g. toxicity, grain size), habitat availability and species diversity.

Here is a relatively recent publication that may be useful:

Huthnance, J. M. (2004), Ocean-to-shelf signal transmission: A parameter study, J. Geophys. Res., 109, C12029, doi:10.1029/2004JC002358.

Try it yourself,

I think you can be successful.

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Sharon, Thank you for sharing answer

It depends what is the time-frame you are interested in.... isostasy, seismic activity....etc.