Science topic

# Physical Oceanography - Science topic

Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.

Questions related to Physical Oceanography

I have a netCDF4 (.nc) file having ocean SST data, with coordinates (lat, lon, time). I want to predict and plot maps for the future. How can I do this using python?

Please recommend a python code for time series forecasting based on this approach.

I have a monthly netCDF4 file containing chlorophyll-a values, and I aim to forecast these values using time series analysis.

My approach involves computing monthly spatial averages for this entire region and then forecasting these averages. Is this methodology valid?

Additionally, could you recommend a Python code for time series forecasting based on this approach?

Is it feasible to predict values for individual grid points without considering spatial averaging?

My study area encompasses an oceanic region of approximately 45,000 sq km near the southern coast of Sri Lanka.

Kindly help me to get a tutorial comprising GIS shape files/raster data to conduct a training programme by using arc/gis-pro for Physical oceanography/coastal mapping (Geology). We have Arc/GIS ver. 10.8.2.

Artificial intelligence (AI) is a rapidly advancing tool. It is heavily reliant on programming languages, data manipulation and analysis. As colleagues in the field of oceanography, I would like to know your opinions on the use of AI in this field. Furthermore, I would appreciate any recommendations for publications that could support your viewpoints.

It is important to be transparent about the limitations in terms of programming for the diferent subfields of oceanography, such as physical, chemical, biological, ecosystemic, and geological; how the incorporation of AI may lead to new disparities in scientific research; and how careful you would be with the use of these tools.

Thanks for your times!

I.S. Gromeka worked at Moscow University after his graduation in 1873. He began working at the University of Kazan in 1880 and became a professor there in 1882, at the age of 31. Gromeka laid the groundwork for the modern mathematical theories of capillarity (1879), so-called screw flow, and flow with cross circulation (1882), which took on great practical importance in hydraulic engineering. Gromeka also studied the unsteady motion of viscous fluid (1882), the propagation of shock waves in fluid in elastic tubes (1883), the vortex motions of fluid on a spherical surface (1885). and a number of cases of equilibrium of an ideal gas.

One of Gromeka's seminal contributions to fluid mechanics was the decomposition of the convective derivative of Navier-Stokes equation, which was later coined after Sir Horace Lamb as the Lamb form, with the cross product of velocity and vorticity being identified as the Lamb vector.

Is there any English translation for the works of I.S. Gromeka? Where can we find his original works in Russian?

I am interested in analyzing satellite-derived swell spectra data from Sentinel 1. This is a L2 product that contains different wave properties for each vignette, which is currently maintained by Copernicus:

Does anyone knows how to access this data? I tried exploring the links available and could only find handbooks and technical information about the data, but not the data itself.

For the RHUM-RUM project, we are writing a SKS paper and I try to review SKS measurements carried out in the context of Mantle Plumes with or without ocean-bottom seismometers.

**Discussion of the state of art on the application of the Ertel's potential vorticity theorem in atmospheric physics & physical oceanography.**Prof. H. Ertel generalized Rossby's work proposal of 1939. Prof. Rossby firstly proposed that instead of the full three-dimensional vorticity vector, the local vertical component of the absolute vorticity is the most important component for large-scale atmospheric flow.

Via an independent paper published in 1942, Prof. Ertel identifying a conserved quantity following the motion of an air parcel proved that a

**certain quantity called the Ertel potential vorticity is also conserved for an idealized continuous fluid.**Several links to check on the topic powered by ResearchGate:

I am interested in the Cenozoic history of surface circulation in the Atlantic Ocean, particularly in the subtropical and tropical regions. However, most information I have found so far is related to the North Atlantic.

In particular, I would like to know if the main currents and countercurrents have changed their intensity, in response to climatic and tectonic dynamics during the last 66 million years. What are the evidences for these changes? What literature would you recomend for solving questions on this topic?

Many thanks in advance.

Are filters the only way or it can be done by following other algorithms.

Physical oceanography

Oceanography

Satellite oceanography

I do not have the PAR data. Fluorescence can be detected from dead particles too, but can it be utilized to get an idea about the euphotic depth.

I need your help and guidance in a paper using ARIMA modeling. I am working on sea surface temperature modeling based on MODIS remote sensing data, ARIMA model has been used with SPSS.

**I am new with ARIMA so results are already obtained but unable to define proper methodology and explain results.**

Well, I am using raster data averages that are in monthly from Aug 2002 toApril2020 (213 months). I used SPSS for ARIMA the model is (3,1,1) (3,1,1). As I am new with this, I need your help to understand the model equation and meaning of these R-squared, R-squared, RMSE, MAPE, MaxAPE, MAE, MaxA, and Normalized BIC in model fitting.

I need to know model equation how to write this and SPSS based results interpretation. Though I have model results already.

Your help will be much appreciated. Would you like to help me with this?

I need recommendation on getting reputable journals in the areas of physical oceanography

I am a 4th-year undergraduate student from BSMR Maritime University, Bangladesh. By curriculum, we have to carry out a thesis (Credit-6) in the final year.

I am interested in physical oceanography, acoustical oceanography, satellite oceanography. But the dear respected guide, if you have a better idea regarding my interesting field as well as other fields which may become important in the near future, you may suggest.

Your kind suggestion will help me a lot.

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!

I'm trying to obtain a gridded bathymetric dataset of a certain region for use in a model, but all of the openly accessible products that I'm aware of (GEBCO, SRTM+) are very poorly constrained by in-situ observations in this region so are mainly based on gravity data. Unfortunately, I know as a fact that this has introduced some major errors (e.g. islands that don't exist).

I have point depth observations for this region from various historical studies which have not been incorporated into the above data products, and I would like to use them to modify the GEBCO grid to nudge depths in incorrect regions but I was wondering if there's an established method for doing this without introducing serious artefacts.

Many papers estimate near-inertial energy flux as the product of wind stress and near-inertial current, where the wind stress is estimated by the bulk formula, which only gives a total amount of wind stress, no matter what frequency it is. Dose wind stress at all frequency could input energy into near-inertial current? If so, how? It will be appreciated if you answer this naïve question.

I want to calculate MLD from CTD data, while going through the literature I found different criteria for density (0.1, 0.3, 0.03, 0.25 etc density difference from the surface). What determines the density difference?

Downwelling due to negative wind curl.

This is in relation to the sampling done at various stations along a cruise track at different times of the day. The surface temperature would be affected by the time of the day it was sampled. How can I eliminate that difference to look at the trend?

I have encountered several ways to detect ocean eddies: Okubo-Weiss, Vector Geometry, winding angle, from SST fronts, etc. However I don't know which one to use. Does a method differ in detecting eddies with latitude or region? I also find that validation of some methods require experts looking at the SLA and geostrophic velocity maps but it has also high uncertainties.

I'm trying to plot U and V vectors in ArcGIS. I followed the method:

In which, point no. 7) Choose <expression> in the drop-down list was not available in 9.3 version.

To do this in other way, I added a field in the attribute table "Rotation".

Using Filed Calculator, I tried the 'function' written in point no. 9)

9). Specify one of the following expression:

Oceanographic Convention: (180/3.14) * Atn2([u],[v])

Meteorological Convention: (180/3.14) * Atn2([u],[v])+180

It was failed due to error in the code.

What is the correct code to write the "Oceanographic Convention: (180/3.14) * Atn2([u],[v])"?

Or is the any other way to plot in Arc?

Thanks.

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

Ice fields significantly limits the wind waves growth and propagation. Is it any instruments to use grided Ice fields in SWAN Wave model?

We have two super moon next January (1st and 31th Jan 2018). If the distance between two super moon is 412 days, how it is possible?

Are the super moons alarm for marine activities?

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?

Hi, everyone.

there are many papers about river plume. But each paper looks from a different facet such as salinity, temperature distribution, density, currents and etc. I need a book to know river plume system basically and comprehensively. can any one offer the book?

thanks a lot.

I want to use ocean data view to view my data (salinity, water temperature and bathymetry) for use in my research

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.

i`m a Master degree candidate,i need a literature'Statistical variability of sea state parameters as a function of wave spectrum' to obtain a formula in it .but i can`t download it anywhere

I want achieve anomaly position of itcz.

I got tired. please help me. it is my method and I know that is unusable

1- get the (apr1980_1.jpg) from grads(use the ECMWF data)

2-I draw itcz line in photo shop(same apr1980_11)

3- Finally achieved this(apr1980_2.jpg)

4-In MATLAB it(apr1980_2.jpg) was Digital

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 have been wondering what would be the best strategy to assimilate moored ADCP and current meter data. In my particular case, I have several moorings (approx. 30) scattered through a regional domain. M2 and K1 internal tides are important in a portion of the domain.

Usually, the uv data is lowpass filtered before assimilation (lets say 48h cut freq.). However, this eliminates any improvement the assimilation can have on the representation of high frequency processes. My experience with HF Radars showed that assimilating data with 2h resolution can reduce phase errors for both internal and barotropic tides.

I wonder if someone else have been assimilating high frequency currents in regional ocean models.

I am using ROMS with strong constraint 4DVar.

SST should be along Arabian sea and Bay of Bengal around Indian Waters.

Dear all, good afternoon!!

I'm running two numerical experiments (HYCOM model) and compare them to a reference (WOA climatology).

My first experiment (control one) gives a bias when compared to the reference: (expt1 - ref). I want to evaluate how the difference brought by the effect introduced in the second experiment (wave-modified surface stress: expt2 - expt1) improve or worsen the model results.

It seems hard to gather everything in a single map since the bias can be positive or negative and the effect brought can over compensate the original bias (move the SST toward the reference more than the original bias and give a new bias of opposite sign).

All I could figure out is to get rid of the sign and use error instead of bias, where error = abs(bias). I have then the error variation: abs(exp2-ref) - abs(expt1-ref). I can divide it by the original error to get the relative variation and know for instance if the original error is over compensated but it gives noisy maps for the whole domain.

I guess I could focus on specific areas like the Benguela resurgence and the Brazil-Malvinas convergence area. Is there any classic approach to show and evaluate this variation in a nice way?

Have a good day,

Nicolas

HI.

I need sea surface salinity data in northwest of Persian gulf near the Arvandrud river. Does anyone know how can i obtain this data? Does anyone know how can i obtain ROPME 2006 data in Persian gulf?

Hello, I need in-situ data include sea surface salinity at near of Arvandrud (Shatt ell Arab) river Mouth in Persian gulf. I am grateful if anyone can help me to find this type of data such as Ropme 2006 databases. Thank you

Trying to get information on the Indian Ocean Dipole cycle!

Abundance, number of species and diversity

I'm aware that K-H instabilities arise when there are two overlying parallel flows of different shear and density. In this case the instability would occur at the interface. What of an instance where the flows are perpendicular? I haven't come across any literature discussing this possibility. Anyone know of a source?

Vertical land movements need to be removed from the tide gauge records in order to convert the time series of relative sealevel change to absolute sea levels. At global scale, the vertical crustal uplift due to the isostatic readjustment of the Earth’s crust and mantle

I am using the SWAN wave model to hindcast waves in an estuary. I have an offshore boundary condition containing some swell energy. I output the energy spectrum in my fine resolution domain but the swell energy does not show up anywhere in the time series. The energy spectrum seems to be shifted toward higher resolution when comparing to field measurements.

if flood basalt is out pored on land as well as ocean then what will be the difference in magnetic behavior over land and ocean??

"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?

I'm working on modelling the propagation and dissipation of waves in both the marginal ice zone and also in the ice pack. My understanding is that in the ice pack we may get both scattering (from changes in ice thickness as described in papers by Squire for example) and dissipation which may occur due to the viscosity in the water (this I know how to deal with) and also the creep effect in the ice. I've found the 1973 paper by Wadhams about this but I imagine that there may be more recent updates on the ice properties ... and that these properties may be different for steady or oscillating loads. I just started to read a few papers by Timco, but I am a bit lost.

So, basically I was going to use Wadhams' theory, with some updates on the mechanical properties of sea ice. Any advice is welcome.

I've read that SST fronts stimulate biological productivity (e.g. Woodson and Litvin 2015, PNAS). But my question is how strong of a SST front is needed to significantly enhance productivity? Of course this will be dependent on a number of factors, but what is a rough estimate? Will a front with 1 ℃ SST change be relevant? Or is this only found with much bigger gradients (e.g. 10 ℃ change)?

I'm particularly interested in the application of this question in the Gulf of California, Mexico.

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

I mean the temperature in the Philippine islands or its ambient maritime landmasses rather than its ambient surface ocean.

Please see attached figure and note the high turbidity belt at 123.6 °E. This phenomenon was captured in March of 2013 (winter). What's the reason? Is it caused by sediments resuspension or other possible mechanisms? Propagating eddies as reported by Nagai et al. (2015)?

Topic :

" Mixing processes and turbulence in the surface and bottom boundary layers in the oceans and lakes"

Kindly if you have then help me ? In advance thank you...

I want to determine light intensity profiles at different depths (down to 1000m) in the North Atlantic ocean. Is there any databases which provide this information ready available?

Does anyone have a reference that gives the exact number, as I cannot find the original paper online anywhere!

Thanks

hi

i want to calculate Froude number in a positive estuary that its water column density and current velocity obtained by using numerical method. To calculate the Froude Number What formula should I use?

Hello ladies & gentlemen,

Does anyone know where I can source high resolution chlorophyll concentration data for the North Sea region from present day back to 2004 for free other than NASA Earth Observations (NEO)?

Any help would be greeted with the upmost appreciation.

Thank you,

Edward Lavallin

Such as in:

Triple collocation

Jur Vogelzang and Ad Stoffelen

Document NWPSAF-KN-TR-021

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?

Many thanks in advance

Matt

I have some tide gauge records (several months) recorded in a semi enclosed basin and need to know the surge fluctuations. I tried T-Tide package to separate tide and surge, but it seems that there are some de-tiding errors in the residuals. Could you please introduce me another software package, code to use?

Hi

I try to use optimal interpolation and kalman filter method of data assimilation for water wave data with fortran and matlab. but before using these methods in wave modeling, I want to test my fortran and matlab codes with simple examples. so I tried to estimate a supposed simple quadratic equation with methods mentioned above but the results are Disappointing. could u plz give me a numerical example that helps me to learn these methods?

We found 40m diameter stone rings around a WWI battleship off Gallipoli, Turkey and can't determine what type of explosive may have caused the impact craters (assuming they are in fact craters).

Article Maritime History of ANZAC Cove

How can I estimate the wave attenuation over Posidonia Oceanica with Simulating WAves Nearshore (SWAN)?

I haven't the program SWAN-VEG (Modelling wave attenuation by vegetation).

There are models for the structure of hurricane winds (e.g. Holland, 1980, Holland et al., 2010) which are typically applied at the the sea surface for studies of air-sea interaction. We know that in the surface boundary layer, under neutral conditions, Monin-Obikov theory may be applied to find the wind speed as a function of altitude and this is an exponential curve (so called "law of the wall"). Is there any reason that the wind direction might also be a function of altitude? Has the vertical profile of wind direction in a hurricane ever been measured (at a stationary point in the hurricane reference frame)?

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

Intercontinental dispersion through the cloud drafts is only a "possibility" which you have suggested, right? Other than not having previous records of the species in India, are there other reasons for reaching this assumption?

We need to study more about dynamics of water temperature due to climate change and its effect on marine organisms in Indian Ocean

I have a series of temperature since 1950 to 2000 year, measured with local station and I have a series of temperature since 2000 to 2015 measured with satellite. I have to combine the series and make some series times. The problem is that I have to normalize o standarize the data because it was measured with differents instruments. Any idea of how to do this? thank you so much.

I have been working on some SAR data Sets like RISAT-1 and RADARSAT-2 , I have extracted the pixel information using python and I would like to know how this information can be used to extract wave and wind information over open ocean

I am correlating pCO2 with fluorescence in the Western basin of the Mediterranean Sea. This basin is oligotrophic, but in the spring blooms can occur. I was expecting during this season the pCO2 to decrease due to the biological activity, but the correlation coefficient is positive. What could be the cause behind that?

We can find on the world wide web many derivatives of the original model (GFDL) based on primitive equations. Is there any text to explain what are the differences between the various models?

What are the chemical and isotopic elements that I have to analyze for detecting marine intrusion?

I would like to have information on the temperature variations in the Pacific Ocean floor as you move north-south or west-east.

Due to subduction beneath various plates pacific is closing ocean. which are the other closing oceans? Is Mediterranean a closing one?

I just start using R and I know there are several specific packages for oceanographers. Can anyone suggest me a good one for physical oceanography?

Thanks ;)

I am looking to read comprehensive texts in Physical Oceanography and in the Evolution and Ecology of Infectious Diseases and am looking for direction into which texts may be the best to acquire.