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# Coastal Oceanography - Science topic

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Questions related to Coastal Oceanography
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Dear All,
I have an issue regarding a sediment transportation simulation. I have computed the sediment transport rate based on a 20 years wave climate, and simulated the sediment drift for the total time span and either by monthly filtering of the data, the monthly sediment transport is also computed. However there is a problem that the summation of monthly sediment transport is much more than what I have calculated for the total time span. Is it possible this happening? Is there any reason behind this?
I appreciate it if you could share your Idea with me.
Best
Saeideh
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.
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Currently, microplastics (MPs) occurence researches in coastal and marine animals are performed in huge amounts, but their results concerning MPs abundances are not always given with the same unity.
• From what I can tell from studies I read, most provide data using MPs/individual. There are some studies that sample in pools, and then, after ending samplings, calculate the MPs/individual data. It would be an issue if we compare MPs/individual data of two different studies: one that sampled in each individual and another that sampled in pools?
• Should a specific study provide just the MPs/individual data? I think this study it would be sort of incomplete, considering that this data would not totally reflect the abundance of animals with different sizes, weights, and possibly ages, etc.
• What is the best approach between other unities, such as MPs/g of the whole sample, MPs/g of their dry or wet weight? That are some formulas to convert samples weight for dry and/or wet. This is applicable for MPs?
I know much of that depends on the study's biological samples, and objectives, but I would enjoy reading researchers opinion about it.
Dear Victor
Mostly expressed as items/m3, but you use another unites according to your specified work too!
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I'm trying to tabulate some concentrations of compounds to eventually test if tide (or depth for other samples) and distance along a sampling transect affect these compounds (the 5 variables on the right). However, the only way I can think to do this is in the attached image, where I'm forced to repeat the distance measurements which results in them getting treated as separate values. If I just split each dependent variable into two based on tide, then I no longer have that independent variable which slows things down quite a bit.
Also, I'm trying to make my Tide variable binary, but I don't see an option for that - perhaps that's also a problem here? Attached is an image of my table.
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
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Hello I want to model the Upwelling phenomenon in the northern part of the Oman Sea Which model or models do you think I should use?
also
I want a model that is not yet complete and can be upgraded
I think, ''Coupled Atmosphere-ocean Mesoscale Model'' would be a batter option in your case. Have a look at the attached article.
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I was drawing plots using ODV software, but I couldn't mask the bottom bathymetry. Can anyone tell how to mask the bottom bathymetry?
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
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I have the following scenario.
In a marine environment, an object X moves below the surface of water from point A to point B. As it moves it displaces water around it which creates ripples (or increases detectable pressure levels) in the surroundings. We have sensors Si installed underwater at distance di with known geographic positions. I want to know the following.
1. How do we measure the intensity I of the ripples (generated by the object) at any sensor Si located di meters away from the object?
2. How do we measure the time required for the propagation of the ripple from its origin to sensor Si such that sensor Si can detect intensity I.
Thanks
Hi Tariq. It was a suggestion i have given. Hope it works.
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Dear researchers,
I am going to estimate the main four tidal constituents (M2, S2, K1, & O1) as well as shallow water corrective terms (f4 & f6) from hourly sea-level observations in a shallow water station based on the Admiralty method. Do you know any open-source package in this regard?
Most of the available packages e.g. t_tide and Utide works based on Foreman (IOS) method and do not provide the mentioned corrective terms.
Thanks
There is a relatively old method to estimate tidal harmonics called UKHO simplified (simply they call it Admiralty method). In this method, the calculations are based on the main harmonic constituents O1, K1, M2, S2 and adjustment for shallow-water fourth- and sixth-diurnal amplitudes and phases (f4, F4; f6, F6).
And thanks for introducing your code. I like to try it for some uneven sea level observations.
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I am aware of computational costs while working with high resolution data, so this question is more of hypotetical nature and is related to the relevance of friction parameter in inundation modeling. The question is also software(model)-dependent.
Thank you Chandan.
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We want to model shoreline change and morphological changes there.
Delft 3D is a good choice
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Has anyone used drogues, quadcopters, blimps and balloons/kitoons for mapping coastal  features and processes e.g. SAV, emergent vegetation, pollutants, oil slicks, bathymetry, currents, etc.?
I used a quadcopter for scanning areas and develop a new map for the area to use it for civil engineering in new projects
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Hi,
I'm trying to merge two chlorophyll datasets from different sensors by applying linear regression on their data overlap. The journal that I'm following log transformed (base 10) the data from both datasets before applying regression, and then used the resulting coefficients to correct one of the datasets. This means I have to log transform all my data to create my merged time series. However, I am hoping to use untransformed chlorophyll in the end.
My questions are (1) is it necessary to log transform the data in this situation, or just directly input untransformed data for regression? (2) If I do use the coefficients from the log-log regression, how should I apply it to the uncorrected dataset? Thank you very much!
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.
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
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I have been looking for information on water column DO, pH, SST , Chl-a, POC for areas in the peninsula near the glaciers vs the Southern Shetland Inland with no luck. Any information available to look for the main differences? Mostly influence of freshwater inputs to the fjords at the peninsula.
Hey Jorge Arigony-Neto ! Thank you very much!
Best,
G
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Can you suggested that the related to coastal water quality index prediction, if any free software there
NDWI index you can use
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I am new to using SWAN (Simulating Waves Near Shore) Model. Is there any helpful guides or tutorials that can be used to explain how to use this software?
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.
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Hello all,
I am looking for Acoustic Doupler Current Profiler (ADCP) which are found to be performing well for streamflow measurement. please share experiences and suggestions for selection of appropriate ADCP for streamflow measurement.
Thanks.
Regards
Rajat
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
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I want to predict shoreline change in the future by the results or data of DSAS software. Could you please give me any advice?
Thanks so much!
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
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CDOM is the colored dissolved organic matter. What makes the fresh water higher in CDOM concentrations than the ocean?
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.
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Coastal management is a topic that has been much debated around the world in the last two decades, in view of the need to organize our coastal areas. In view of this context, I ask if the countries of South America present governmental programs of Coastal Management.
Hi Fabio
Best regards.
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When polar jet stream has southward shift mandering happens, it leads to polar vortex.
It is also true that the magnitude of polar vortex depends on the temperature difference between poles and mid-latitudes.
Moreover, the southward shift of jet stream is related to the southward shift of ITCZ (Intertropical Convergence Zone)
Then, Why polar vortex is not a regular phenomenon?
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:
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Hello Everyone.,
I am having confusion regarding to calculate wave breaker angle.
wave breaker angle was calculated as the difference between the peak wave direction and the direction normal to the depth contour.
I don't know how to find breaker angle in the right manner.
Thank you in advance, who helped me
This paper may help in your research Direct Formula to Compute Wave Height and Angle at Incipient Breaking, JWPCE, ASCE
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Please let me know the characteristics of MEGA Projects.
Which type of projects is termed BIG RESEARCH PROJECT or MEGA project?
Dear Dariusz,
Many thanks to you indeed for your suport.
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I am using a paper by Hamada et al. (2012) to guide me through this.
"A year is classified as a positive (negative) IOD
year when the five month running average of the DMI having
a standard deviation equal to or greater than 1 (−1) for at least
four consecutive months in the analysis year." (Hamada et al., 2012, p. 70)
This may be an obvious question. However, does this mean that the index is normalised and then the 5 month running mean computed? Or is it the other way round?
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.
To remove time scale variability you have to take running mean of particular interval, depend on your interest of variability. Then go for DMI calculation.
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Dear all;
I want to calculate the weight of anchor for a fish cage in the sea. This fish cage has a circle shape and is built by buoyant structures for floating on water surface, net is connected to this structure and an anchor to sustain the cage in the sea.
Would you please introduce some references for calculating the weight of proper anchor for this structure?
The schematic figure of this cage is attached with this question.
Best Regards,
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
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I have wave spectra time series and I use some partitioning and tracking algorithms to identify swell events and wind sea events. My aim is to model separately frequency time evolution in a swell event case and a wind sea event case.
- In case of swell event, since the swell celerity in deep water is g/(4pf), the frequency of waves generated at a single remote location and arriving at some observation point increases linearly with time. According to this, I choose an increasing linear model for pic frequency time evolution in a swell event.
- Now, what kind of model can I choose in wind sea event case? Actually I use a decreasing linear model assuming that the energy transferred by wind to sea water contribute to decrease the frequency. Is it a coherent hypothesis? Can you recommend another model to me?
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I need your help in finding literature on the evolution of a river bar in the tide-dominated delta. Also, I want to know about the methodology which I can follow to know about the evolution/formation of a river bar.
Supriti
Maybe, this book can help you, "FUNDAMENTALS OF FLUVIAL GEOMORPHOLOGY" Ro Charlton.
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I have a deep sea sedimentary core of 4.3m length. I subsampled the whole core with 1cm interval. Now,I would to do microfaunal analysis. So, I need suggestion for selecting sub sample for better microfaunal analysis.
Respected Dr.C.T.Schafer,
Thank you for your valuable information .
Sincerely,
Thamizharasan
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Currentmeter data (u, and v current, and temperature at 35m depth) have no correlations with local longshore wind. However, if I calculate the theoretical Ekman transport (or upwelling), I get some reasonable numbers. I am wondering if I can invoke the above lack of correlation to ignorer Ekman theory in my study region. Or should I proceed with some caution by assuming only a fraction of the theoretical Ekman transport actually occurs despite no correlation between wind and current? Where should the factor for the fraction come from? There is one limitation: I don’t have measurements at depths shallower than 35 m to look at correlations with the wind. The Ekman depth at my location is roughly 30 m.
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.
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To plot the processed ADCP Data
If you are processing moving-vessel ADCP data, here is the most robust method ---Velocity Mapping Toolbox, developed for ADCP.
Regards,
Hao
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Hi guys,
By analysing the microbial metagenomics, I found lots of genetic traits related to metal resistance and organic remediation, suggesting the water pollution in ambient seawater.
I've heard that Kaneohe Bay used to be a good snorkelling place in early 90s but then it was polluted.
I am not familiar with the marine chemistry/pollution field, if anyone has the data or knows where I should look at, please let me know. Thanks in advance.
Kind. Fang
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!
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Im looking for a set of suitable data and methodology for mapping ocean bathymetry. Kindly suggest some sources of data and methodology. I will use those data for mapping the ocean floor of Bay of Bengal in Bangladesh portion.
Thanks, Shareful
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.
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I am looking for information relating to population level responses to diminished sea ice, specifically after the mortality event on Wrangel Is in 2007. I am interested in gathering literature from the Russian side of the Bering and Chukchi Seas. I have only been able to find the following 3 docs:
Kochnev (2002) Factors causing Pacific walrus mortality on the coastal haulouts of Wrangel Island
Kavry et al. (2008) New coastal haulouts of walruses--response to climate changes
Ovsyanikov et al. (2008) Unusual Pacific walrus mortality at Wrangel Island in 2007
Hi Anatoly,
Jenell
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I am working with the distribution and diversity of coral species and I would like to know if there is an online database where I could download spatial marine data (an analogue to the WorldClim database), focusing on bathymetry, sea surface temperature, etc. Any suggestion is welcome.
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).
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I am analysing a coastal time-series of hourly temperature and salinity measurements. I have calculated the density using Gibbs seawater toolbox (TEOS10). In addition I have also calculated the seawater density/stability ratio $R_{\rho}$,
$R_{\rho} = \frac{\alpha \Delta\Theta}{\beta \Delta S_A}$.
Specifically, I want to distinguish between density changes affected by either changes in temperature or salinity. So far I have just seen articles analysing the spatial distribution of the density/stability ratio, either vertical or horizontal, and mentioning that when $-1 < R_{\rho} < 1$, the density is affected mostly by changes in salinity.
Could anyone please suggest further references, especially analysing this ratio using time-series?
Cheers!
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
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The quality of ocean circulation model is lower than wave model provide, I mean
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
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Hello.
As per title, I was wondering if the Wind and waves atlas of the Mediterranean Sea is freely accessible, and if it is, from where (and/or from what institution).
Best
Gm
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.
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I want to see different water masses in the Bay of Bengal..Like at certain which water comes..For ex. At  bottom atlantic bottom water, at some depth Central indian ocean water, etc. Can you suggest me some research papers.
Thanks Danial..This was really useful for me.
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I'm working with water quality in lakes, I need to calculate the energy budget of a lake. I have meteorological information (PAR, temperature and wind speed) and also the water temperature and the volume of the lake. Can anyone please provide references?
Dear G.Caniaux,
Thank you so much for the references.
Best Regards,
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Dear every body
The power plant is 70 km away from Persian Gulf, I Will inform you step by step.
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
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Accretion increases with period of inundation and tidal flats are inundated for longer than saltmarshes. However, vegetation increases sedimentation capture.
Thanks Norman, I will follow that up. I am working in that same estuary myself!
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I would really thankful if anyone guide me to know how I can model thermal discharge of hot water outfall in marine environment in a way to consider both near and far field. I mean that the model should simulate plume of hot water as near field and also hot water diffusion as far field modelling.
Thanks
You can use Mike 2016 and Cormix software.
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I found that there are contrasting opinions in the correct application of the equation of state for freshwater proposed by Chen and Millero, 1986.
Should the in situ or the potential temperature be used?
Chen, C-T. A., and F.J. Millero, 1986, Precise thermodynamic properties of natural waters covering only limnological range, Limnology and Oceanography 31(3):657-662
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, RhoP as a function of its in situ temperature (t), salinity (S) and pressure (P).
Should you wish to compute the potential density, RhoTheta, 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: RhoTheta = RhoP(Theta, S)
Theta itself can be calculated from t, S and P using a potential temperature calculator freely available online.
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I am looking for in-situ measurements of wave heights for the Caspian Sea. I see that people published a comparison of wave modeling results with the in-situ data, so there are data from at least a few stations available, like Anzali, Neka, Amirabad, Fort-Shevchenko, Neftyanye Kamni, Kochubey, Astrakhan, Makhachkala, but simple googling does not show any downloadable data. Do you know where can I get the data, whom to ask and how open they are?
Many thanks!
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 :
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From where i will get free bathymetric map of Indian ocean for research purpose?
the scale should be 1: 5000 to 1:10000
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.
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I am trying to use the generalized modes on WAMIT to simulate free surface movement, but when I try to modify the newmodes.dll file WAMIT doesn't working, sending the message: "Error 0007: Error loading import library.newmodes.dll".
I have been trying to modify the dll using Intel Visual Fortran, as recommended in the manual, but it's a more recent version of it. Now I am not sure if I am using the correct procedure, so if anyone could help me with this, maybe with a tutorial or anything, I would be really glad.
Thanks for the help in advance.
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Seto Inland Sea, the largest semi-enclosed sea in Japan,
Some researchers provide the M2, S2, K1, Ovalues of the main strait of the Seto Inland Sea, Some provide the mean surface current of the whole Seto Inland Sea, which one or someone else is the best descriptor of the current speed? I want to investigate the influence of current (speed) on water stability and red tide occurrence.
Thank you!
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.
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Please can anyone give me the average ranges for sea surface temperatures, atmospheric pressures, sea water density, salinity, depth and bathymetry, ocean current, wind speed and other metocean data for the North Sea, particularly for the Danish, Dutch, Norwegian and UK sectors?
Do not hesitate to ask me if need further help.
Rzger
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Is anyone working on modeling how changes to coral reefs may change coastal erosion models.  This is something I am very interested in getting into and is wondering if anyone would be interested in collaborating or has suggestions on who to speak to.  Thanks!
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.
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Hello,
I want a complete database on dams in North Africa (Morroco, Algeria, Tunisia).
I have already collected a databases "GRanD" and "AQUASTAT" , but they only contain large dams. I want to complete my database by small dams.
Thank you in advance if you have ideas to find these small dams.
Global database of dams (but I´m not sure that it includes small dams):
UNEP GEOdata from United Nations Environment Programme:
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Would you be so kind as recommend me where to find in open access The Black Sea hindcast wave heights and periods time series at few nearshore (deep water) positions for 20 – 40 or more years duration.
The hindcast data are needed for our international project of Russian Foundation for Basic Research about coasts evolution under the changing climate.
Sincerely yours, Sergey
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
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Good morning.
My name is Mada Triandala Sibero. I'm student from Diponegoro University.
I'm a beginner in marine science field especially for sponge identification.
I got this sponge as my sample. According to the shape, it supposed to be Cinachyra sp., but according to spicules identification I don't find any journals shows the Cinachyra sp. has spicules like star shape.
I really need an explanation according to my result. And please correct me if there is any miss understanding.
I really hope there is someone in here could help me.
Thank you very much.
Hi Mada, you need to post some photos of the different types of microscleres present in the sponge to get an ID
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Every tidal channel has one flood tide dominated side and anoter side is ebb tide dominated side. In any tide-dominated and tide-influenced delta, every channel has flood-tide and ebb-tide dominated side but not on same side, every channel has distinct characteristics regarding flood tide and ebb tide dominated side. I want to know about the reason of this.
Hello Supriti,
since hydrodynamics are the active force and the sea bottom the responding one, Thomas is quite right to give the Coriolis force credit for the existence of flood and ebb channels by provoking a shift in the direction of currents thus leading to a diversion between flood and ebb channels. But it does not fully explain the phenonema, since e. g. in tidal inlets there are sometimes flood channels on both sides of the ebb channel which is only explainable due to interactions of currents and and bottom topography. This has been excellently described by van Veen in 1950; his contribution was transferred into English by Ad van der Spek, Marcel Stive and Tjerk Zitaman and published 2005 in the Journal of Coastal Research. You will find the full text on the RG-page of Tjerk Zitman.
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Hi,
I am having some problems with the space varying temperature file in FLOW module.
I have prepared a space varying temperature file for my project (part of which is shown below):
FileVersion = 1.03
Filetype = meteo_on_equidistant_grid
n_cols = 3
n_rows = 4
grid_unit = degree
x_llcenter = -9
dx = 1.5
y_llcenter = 57
dy = -1.5
NODATA_value = 999.999
n_quantity = 1
quantity1 = air_temperature
unit1 = Celsius
TIME = 0.0 hours since 2013-09-01 00:00:00 +00:00
10.255 12.162 13.800
12.161 12.614 12.984
12.931 12.974 11.971
12.995 13.184 12.951
and I am including these files in the mdf file as specified in the FLOW manual:
Commnt =
Wnsvwp = #Y#
Wndint = #Y#
Commnt =
.
.
.
Commnt =
Filwu = #ERA_Interim_092013_072014.amu#
Filwv = #ERA_Interim_092013_072014.amv#
Filwp = #ERA_Interim_092013_072014.amp#
Filwt = #ERA_Interim_092013_072014.amt#
Commnt =
However, the model doesn't run and I got the following error:
*** MESSAGE Air temperature specified on a separate equidistant grid
*** ERROR Air temperature is not used in heat model (ktemp) = 0
Can anybody please help me with this or point to some possible errors I may be making?
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
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Hello All
I like to know, whether there is a way to statistically calculate the percentage difference in Phases of two tidal water levels signatures?
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"Cold upwelled water alters local weather. Weather onshore of regions of upwelling tend to have fog, low stratus clouds, a stable stratified atmosphere, little convection, and little rain." from the book "Introduction to Physical Oceanography "(Robert H. Stewart). If the upwelled water in the coastal area is relatively warmer than ambient water, how does it change the local weather?
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.
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So far I have listed the following 3D models: Pechon and Teisson (1996); Gessler et al. (1999); Lesser et al. (2004; part of the "DELFT3D Suite).
Similarly, I know about the following Q3D models: Ding et al. (2006); Saied and Tsanis (2005); and Hanson et al. (2010).
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!!
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Plotting real tidal data from different regions and different tidal reference stations, it is clear that some tidal datums often have the same relative position.
Trivial examples are the relative positions of the Lowest High Water (LHW) and the Highest High Water (HHW); or of the Mean Lower High Water (MLHW) and the Mean Higher High Water (MHHW) in a semidiurnal cycle.
However, the relative position of some other datums does not appear as trivial, especially when considering the neap-spring synodic cycle.
For example, the Lowest High Water Neap (LHWN) can be lower or higher than the Highest Low Water Neap (HLWN), i.e. the range of the neap high tide can overlap or not with the range of the neap low tide. Another example is the relative position of MLHW and the Mean High Water Neap (MHWN).
I wonder if there is any classification of tidal regimes that describes these types of patterns, that is or might be related to geographic areas, or ecological patterns.
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
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i'm confused on the differences between PSS and PSU for ocan salinity measurements. Im wondering are there any differences between them or almost similar??
Can anyone give me suggestion on how can i convert salinity unit from PSS to ppm or ppt? since most of my sources only convert between ppm,atm and other except PSS
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
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I work on a numerical model for investigating the structure of density and salinity in tidal estuarine system. I calculate d Richardson number using of formula. But amount of RI number are very variable, for example  0 to 5000. Are these amount of RI number correct? And what is its range?
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.
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I would like information about tsunamis in South Atlantic.
Thanks.
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
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I have 10 U and V component wind data, retrieved from ECMWF era-interim reanalysis data. I know how to calculate magnitude and direction of wind from U and V component. I don't know the way to do for all positions.
Hi vasudevan
This can be done in many ways according to your choice of platform or software.
Data visualisation and analysis tools like Ferret, Matlab,cdo etc  will do your needs.
sample script in matlab to do it : modify according to ur need
nc_dump(s(1).name) %% see the description of variables
lat=nc_varget(s(1).name,'lat'); %% change the varible name as in ur file
lon=nc_varget(s(1).name,'lon');
uwnd=nc_varget(s(1).name,'u10');
vwnd=nc_varget(s(1).name,'v10')
windspeed=sqrt(u.^2+v.^2);
(PLZ  note For matlab  sometimes u may need SNCTOOLS for carrying out the analysis with netcdf files : http://mexcdf.sourceforge.net/ )
best regards
shanas
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I need Coastal slope or Bathymetric image for Bay of Bengal coast specially Sundarban coast. Is there any agency or govt. Website which can provide freely bathymetric images? I was passing through DGH and GEBCO but it’s not freely available. Is there any others agency for bathymetric data??
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.
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I am working on fish ecology in an Indian estuary. However, proper identification of species belonging to Mugilidae is very difficult particularly of the genus Mugil and Liza. Most of the references available (FAO identification sheets and some Indian keys) differentiate the species based on the premaxillae shape which is difficult to ascertain in juveniles of the family. Also the family is highly dynamic with many new or updated genus and species. So, are there any recent comprehensive taxonomic keys available for the family from the Eastern or Western Indian Ocean regions?
A new book: Biology, Ecology and Culture of Grey Mullets (Mugilidae)
Donatella Crosetti, Stephen J. M. Blaber, have a chapter on The Biogeography of Mugilidae in India, South-East and East Asia, this could help.
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So far I have found a relative paper by Suh and Dalrymple (1987). I am specifically interested in detached (offshore) breakwaters.
Antonios,
Please have some refs. attached; perhaps general but maybe they will help.
Best regards,
Greg
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Hi all,
I'm seeking a long-time beach profile model, either process-based or not is ok. I'm interested in the Xbeach developed by delft, but it is said it is mainly used to simulate the response to storm so it is a short period model. Has some one used it for long time modelling? Or is there other suggestions?
Thanks!
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
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There is no doubt that in summer, a Kuroshio bottom branch current northeast of Taiwan can intrudes into the eastern China coast around 28 °N, and then turns northeastward to Yangtze River Estuary. Does it exist in winter but attribute   to different forcing and/or sustaining mechanism?
I suspect it is. Other mechanism could be the frontal trapping of buoyant coastal current (Chapman and Lentz, 1994).
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Is there any specific method for identifying the significant wave height in coastal vulnerability assessment?
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)
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I have a set of wave data modeled by SWAN. As SWAN doesn't compute breaking wave height, is there any way to extract it from the data?
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.
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Dear Balasubramanian
The HydroC™ CO2 sensor is a unique underwater carbon dioxide sensor for in-situ and online measurements of dissolved CO2.
karbassi
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Hello all,
I have a wave buoy time-series of significant wave height (Hs) and wave period (Tz). I want to separate the series into swell (long wavelength, far field) and locally generated wind wave (storm) components for some further investigation into wave-tide interaction. Is there a theoretical limit that I can use to classify if a wave observed at time t; Hs(t) and Tz(t), is a "swell" or "storm" wave?
Matt
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.
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Tidal variations might affect the results. So, how can I consider tidal variation in a scientific way?
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
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If trapezoidal integration method is used, it provides value with units of mg/m2 (which is per area) but I need to know is there any way to get chlorophyll value for entire water column in terms of mg/m3 (which is per volume)?
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.
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1. Chlorophyll a concentration at three sampling points of a study coastal location. (The distance between sampling locations from coast varies between 10 - 25 km).
2. Chlorophyll a concentration taken on one day of different months in a year but one season.
(For instance, for year 2002 taken on 12-3-2002 and for year 2003 taken on 14-2-2003)
3. Chlorophyll a measured at 3 depth levels.
If data availability is in above mentioned manner, can we prepare annual time series for the study location? how?
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
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I study on the coastal zone in presence of submarine vegetation (Hyères, Var, France).
I want to mesure the bathymetry here.
How can we ditermine the presence / absence of the submerged vegetation?
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.
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With respect to studies on Marine and Coastal waters, Is there a difference between the meaning behind use of words "Water Quality Parameters" and "Environmental Quality parameters"?