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# Oceanographic Instrumentation - Science topic

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I' m using Argo floats to investigate Agulhas eddies vertical structure and need to calculate temperature anomaly from these data. My temporal coverage is from 2008 to 2013. Which climatology is the most suitable in this case? I've using anual means but the Argo profiles seem a lot more warmer than I would expect. I am using MatLab to do the calculations but help from python users is welcomed as well.
How can I calculate total temperature increase/decrease over the last 10 years ?
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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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Interested on whether oceanic DMS concentration can be detected by satellite image. Only found a couple of inconclusive references from 1990s. While I have your attention, is DMS  and Chla correlated? Many thanks!
To date the only climatologies that I'm aware of come from dynamic simulations, or through statistical models.
There are a lot of studies that have tried to link chla to dms, but there are also relationships with mixed layer depth, as well as species composition of phytoplankton. And all those relationships differ by region as well.
So in short, no, DMS cannot be measured from satellite (but who knows where technology may go!)
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Hi all,
I'm looking for references regarding the implementation of WW3 for the NE Atlantic by IFREMER. I have access to the hindcasts through the IFREMER ftp but I can't find any reference regarding the implementation. Can anyone help with this.
Hi guys,
the latest hindcasts are at
if you are looking at rectangular grids, yes the latest reference is Rascle & Ardhuin (2013). For the triangle-based grids, there are extra coastal effects described in Roland and Ardhuin (Ocean Dynamics 2014) :
And if you are interested in infragravity waves
the proper paper would be Ardhuin et al. (Ocean Modelling 2014)
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Please see the attached dialog box and header file. During the processing profiling CTD data (SBE 25 or 25plus), how to set up these parameters? I can't understand the "surface soak depth" well.
Hi, Thierry
Thank you for your detailed explanation. I got it.
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Lower resolution CTD can miss too much of the detail maybe?
Not sure about 1KHz, but if you wanted to callibrate before casting them, controll environment is the best as Mr jf Argentino suggested. And as for more the manufacture information must be kept in mind for accuracy n resolution for those sensor.
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This may help to compare  ocean acidification studies.
For ocean CO2 data, there are a few major databases, many of which have inconsistent inclusion of other data (e.g. pH, O2), but all of which should have S and T at least.  These include:
http://cdiac.ornl.gov/oceans/ (lots of moored and underway surface ocean CO2 data)
The next version of SOCAT will have more parameters such as pH, but will still only be ocean surface data.
For water column data, you can check out GLODAP (likely to have many data sets with multiple parameters for ocean acidification work): http://cdiac.ornl.gov/oceans/glodap/GlopDV.html
The US National Centers for Environmental Information databases (likely to have many data sets with multiple parameters for ocean acidification work): https://www.nodc.noaa.gov/access/
Good luck.
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VGPM- Vertically Generalized Production Model
SeaBAM model
I might suggest some absorption-based approaches, especially for coastal area, here are two examples:
Smyth, T. J., G. H. Tilstone and S. B. Groom (2005). "Integration of radiative transfer into satellite models of ocean primary production." J. Geophys. Res. 110: C0014.
Barnes, M. K., G. H. Tilstone, T. Smyth, D. J. Suggett, R. Astoreca, C. Lancelot and J. C. Kromkamp (2014). "Absorption-based algorithm of primary production for coastal waters for total and size-fractionated phytoplankton." Mar. Ecol. Prog. Ser. 504: 73-89.
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Apart from the fact that the latter is not dependent on the concentration of suspended particles, what about general performance? I'd appreciate to know about the experience of someone who used both
Dear Nathan,
Thanks for your reply. In fact I just need the best possible estimation of the horizontal current at a fixed point. Current speed module and direction in N-S, E-W coordinates, that's all. My interest is to obtain time series of the current itself at the depth of deployment of the meter, and also to compute (horizontal) suspended sediment flux by means of a coupled turbidimeter.
Best regards, Jacobo
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Hello everyone,
Have any of you used CT scans of sediments to get a density profile/trace? Specifically, I am working with marine and lake sediment cores. I have used CT scans before for their imagery and have exported profiles of their densities based on their grayscale values in ImageJ, Sante DICOM Viewer, and Osirix, but we'd like to move into using our CT scans a bit more quantitatively. I processed the dicom files with the same window and level settings within individual cores, but was not always able to use the same settings from one core to another when I created images (.jpegs, .tiffs, etc.) from the dicoms (sandier cores would be washed out or muddier cores would be too dark to see detail otherwise). Now, though, we'd like to access the actual, or as close to actual, densities as possible. I've read a little bit about calibrating CTs to a known value (I was thinking air that got imaged around the cores, or their PVC/plastic core liners) and about using the Hounslow scale to at least approximate actual densities. I was wondering if a) anyone's got any thoughts on finding good ways to tie CTs to actual densities, and b) if anyone can think of any pitfalls to watch out for while I do this.
Thank you for any help or suggestions you can give!
- Bran
Hello Mihai and Ferdinand,
Thank you both for responding so quickly! Mihai - looks like you've confirmed some of my concerns about properly calibrating my scale. I think it's going to take some special consideration. Thank you for the link, Ferdinand. I will take a look.
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I need that for a very short experiment in Mallorca. Any info will be wellcome. Thanks
OK thanks!
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Really...Practical, but unit-less or unpractical, but unitized? Is it important to have salinity defined in SI units? What percent of your data expressed in the Absolute salinity units, compare to the Practical salinity?
I am asking question from the point of a manufacturer of the oceanographic instruments, where implementation of the Absolute salinity as derived parameter is under process of discussion. Would users of  the CTD probe be satisfied to obtain in derivations instead of geo-position defined Absolute salinity, simply defined Reference salinity, expressed  in g/kg ?
For the majority of applications, Sp is fine and it should continue to be reported in papers. Conversion to Sr is very straight forward, simple and easy to adopt for those that are ready to adopt it. For the few applications that need Sa conversion is not as straight forward but fairly simple with a little extra knowledge of the sample.
Whether an instrument reports Sp or Sr probably isn't important at this point as long as the user knows which it is. From there it's easy to convert as needed for comparison with historical data. Adopting Sr will not cause a break with historical records, but people have to be aware of the difference. Implimentation of Sr is important and should be done even though it will take a long time to fully transistion. PSS-78 kicked the can down the road and now it's time to address the issue. I think it's great that instrument companies are intrested in doing so. For the forseeable future Sa will have to be calculated and implemented by the user.
As with any paper it's very imporant to define all your methods and units, so it's extremely important for all published papers to define which salinity they are using and how it was determined, doing so will make the transistion to Sr much easier and prevent breaks or confusion with historical records.
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I have data in shapefile format and want to use in ODV.
Hello,
With ODV you can use * .txt files, and import them. The data must be in matrix format.
Attached you can find a sample file
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I downloaded STAPLOT tools, but when i run this tools this error appears:
??? Error: File: sta_plot.m Line: 234 Column: 13
"xlim" previously appeared to be used as a function or command, conflicting with its use
here as the name of a variable.
A possible cause of this error is that you forgot to initialize the
variable, or you have initialized it implicitly using load or eval.
Take care that you hardly can Obtain SST (sea SURFACE temperature) from CTD as you should usually discard first few meters in CTD data. At most you could interpolate maps of sea temperature at, let's say, 5 m depth, definitly NOT surface. :)
Concerning the error, as Ricardo said, you have a variable in workspace named as a matlab function, xlim. CHange the name of your variable.
Cheers
Antonio
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As above.
Thanks Emmanuel! I'll have a look at the options you suggest.
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