Search found 35 matches

by ptimko
Thu Sep 01, 2022 10:25 pm
Forum: ROMS Discussion
Topic: How to correct HYCOM SSH before using it as OBCs in ROMS
Replies: 4
Views: 2021

Re: How to correct HYCOM SSH before using it as OBCs in ROMS

Monthly means for HYCOM should be available here: https://data.hycom.org/datasets/GLBb0.08/expt_93.0/data/meanstd/ The files are in native HYCOM format but there maybe a utility for converting the files to netcdf format in the source code under utilities or tools, looks like there may be some python...
by ptimko
Tue Dec 25, 2018 4:53 am
Forum: ROMS Discussion
Topic: How to get boundary condition from new data Hycom for COAWST
Replies: 4
Views: 3238

Re: How to get boundary condition from new data Hycom for CO

Have you tried looking at the HYCOM forum for answers at www.hycom.org? If you are having difficulty accessing or downloading HYCOM data it would probably be best to place a question in the HYCOM forum as they understand their data server the best. In most cases they are able to resolve user problem...
by ptimko
Wed Dec 14, 2016 10:22 am
Forum: Job Opportunities
Topic: Ocean renewable energy modeling post - Bangor University, UK
Replies: 1
Views: 2980

Re: Ocean renewable energy modeling post - Bangor University

As a former employee I would be happy to provide anyone with information about what it is like to work in the School of Ocean Sciences at Bangor University. Please feel free to contact me at pgtimko1@yahoo.ca
by ptimko
Sat Jun 04, 2016 9:15 am
Forum: ROMS Discussion
Topic: Hycom-Ncoda in PYROMS
Replies: 2
Views: 3517

Re: Hycom-Ncoda in PYROMS

Are you trying to read native HYCOM (*.[ab]) output files? If it is a global dataset then the data are on a global tri-polar grid, which is not rectangular. There should be FORTRAN routines available on the HYCOM website for converting native HYCOM (*.[ab]) to netcdf (*.nc) which might help. At leas...
by ptimko
Tue Dec 23, 2014 7:21 am
Forum: Job Opportunities
Topic: 4 year research fellow in marine renewable energy - UK
Replies: 1
Views: 3693

Re: 4 year research fellow in marine renewable energy - UK

If anyone wishes to receive further information about working in the School of Ocean Sciences at Bangor University please feel free to contact me at p.timko@bangor.ac.uk
by ptimko
Sun Nov 30, 2014 12:56 am
Forum: Job Opportunities
Topic: PhD in marine renewable energy modelling - UK
Replies: 1
Views: 3190

Re: PhD in marine renewable energy modelling - UK

For further information regarding studying and working in the School of Ocean Sciences at Bangor University please feel free to contact me at p.timko@bangor.ac.uk
by ptimko
Wed Aug 06, 2014 8:25 am
Forum: ROMS Discussion
Topic: Failure when change the grid in upwelling case
Replies: 3
Views: 2899

Re: Failure when change the grid in upwelling case

Something must be mismatched. I'm not sure I understand why your grid stiffness ratios are changing if you are using the same bathymetry. For your own climatology case you are trying to set up. Have you check the coastline for single point seas? If it's blowing up near the boundary you may want to c...
by ptimko
Tue Aug 05, 2014 5:50 am
Forum: ROMS Discussion
Topic: Failure when change the grid in upwelling case
Replies: 3
Views: 2899

Re: Failure when change the grid in upwelling case

If the model is blowing up with 2 time steps it sounds like you're violating the CFL criteria. Try using a smaller time step.
by ptimko
Sat Jun 14, 2014 7:10 am
Forum: ROMS Discussion
Topic: tidal analysis of large output files
Replies: 22
Views: 21258

Re: tidal analysis of large output files

Thanks for correcting me. Now that I've thought about it more you don't need to hold the time series in memory. I'll take a look at the AVERAGES_DETIDE option.
by ptimko
Thu Jun 12, 2014 11:25 am
Forum: ROMS Discussion
Topic: tidal analysis of large output files
Replies: 22
Views: 21258

Re: tidal analysis of large output files

Thanks for the additional input. My biggest concern with implementing tidal analysis in ROMS is the memory requirement. If you wanted to include the four largest semi-diurnal and four largest diurnal constituents (M2, S2, N2, K2, K1, O1, P1, and Q1) you would need 183 days of hourly data. That would...
by ptimko
Wed Jun 11, 2014 7:21 am
Forum: ROMS Discussion
Topic: tidal analysis of large output files
Replies: 22
Views: 21258

Re: tidal analysis of large output files

It think it would be rather difficult to implement harmonic tidal analysis within the code since it would require that they entire time series be held in memory. For a large domain that could impose some serious memory usage issues; especially if one wanted to study the 3-D tidal currents. You'd pro...
by ptimko
Tue Jun 10, 2014 12:48 am
Forum: ROMS Discussion
Topic: tidal analysis of large output files
Replies: 22
Views: 21258

Re: tidal analysis of large output files

Probably best to do the tidal analysis using FORTRAN code on the supercomputing cluster. I did this when I analysed an 8 Terabyte dataset for 3-D global tides from HYCOM. Foreman's FORTRAN harmonic analysis code uses the same algorithm as matlab t_tide but doesn't provide 95% confidence intervals.
by ptimko
Sun Apr 20, 2014 12:35 am
Forum: ROMS Problems
Topic: compile error for inlet_test
Replies: 3
Views: 2132

Re: compile error for inlet_test

I believe the correct flag for ifort is -free
by ptimko
Tue Feb 04, 2014 1:23 am
Forum: ROMS Discussion
Topic: ROMS blows up after define MASKING
Replies: 1
Views: 1865

Re: ROMS blows up after define MASKING

Question... Why do you have periodic boundary conditions? you say you're trying to model: I am using ROMS model configured for the Arabian Sea in northern Indian Ocean. but your output file says your boundary conditions are: Lateral Boundary Conditions: NLM ============================ Variable Grid...
by ptimko
Wed Jan 29, 2014 12:44 am
Forum: ROMS Discussion
Topic: Problem with large size initial files
Replies: 10
Views: 5793

Re: Problem with large size initial files

Thanks for the input, I have plans to run similar size grids myself when I get back to work! :)
by ptimko
Tue Jan 28, 2014 12:54 am
Forum: ROMS Discussion
Topic: Problem with large size initial files
Replies: 10
Views: 5793

Re: Problem with large size initial files

thanks for the input... previous message spcecified that the complile flags were: mcmodel=large and i-dynamic that's why I was suggesting an error in the input file and/or a code bug. You're could be right about memory limitations. I've run larger grids for global tide simulations using another mode...
by ptimko
Mon Jan 27, 2014 12:57 am
Forum: ROMS Discussion
Topic: Problem with large size initial files
Replies: 10
Views: 5793

Re: Problem with large size initial files

I'm kinda stuck, I'm currently out of my office and don't have access to the source code to look at the routines themselves. It appears that there is a problem with the way that the variable GridNumber is defined. Is it possible that you are missing or have incorrectly specified something in your in...
by ptimko
Sun Jan 26, 2014 4:21 am
Forum: ROMS Discussion
Topic: Problem with large size initial files
Replies: 10
Views: 5793

Re: Problem with large size initial files

with ncpus=12 are you running the code with OMP on a single node?

you might want to try compiling under mpi and using 2 or more nodes.

might depend on your job script....
by ptimko
Sat Jan 25, 2014 1:38 am
Forum: ROMS Discussion
Topic: Problem with large size initial files
Replies: 10
Views: 5793

Re: Problem with large size initial files

What is the physical memory of the system you are using?

Patrick
by ptimko
Sat Nov 23, 2013 1:44 am
Forum: ROMS Discussion
Topic: Problem with upwelling case
Replies: 9
Views: 4481

Re: Problem with upwelling case

What compiler are using? what compiler options are you using? and what is your computing platform? If you have alternative compilers available or alternative platforms available you may want to see if you can replicate the problem. It may help determine if it's compiler or platform specific. Patrick
by ptimko
Thu Nov 21, 2013 1:12 am
Forum: ROMS Discussion
Topic: Problem with upwelling case
Replies: 9
Views: 4481

Re: Problem with upwelling case

Another thought just occured to me, You may be trying to print an unprintable ascii or ebcdic character (such as a tab character, control, EOL, etc) for your system. Not sure why that would happen either...

Patrick
by ptimko
Thu Nov 21, 2013 1:01 am
Forum: ROMS Discussion
Topic: Problem with upwelling case
Replies: 9
Views: 4481

Re: Problem with upwelling case

I've never seen output like that before... I'm wondering if maybe you have a NaN or Inf in your input/output somewhere. Another possibility might be an out of range value that can't be represented by the field descriptor on output. The representation of NaN's, Inf's, or out of range values may be sy...
by ptimko
Wed Nov 20, 2013 1:35 am
Forum: ROMS Discussion
Topic: Problem with upwelling case
Replies: 9
Views: 4481

Re: Problem with upwelling case

This probably isn't going to help much but I checked on Wikipedia and to answer your first question: "What are those characters?" I found the following: The at sign, @, normally read aloud as "at", also commonly called the at symbol or commercial at, and less commonly a wide rang...
by ptimko
Tue Oct 29, 2013 12:48 am
Forum: ROMS Adjoint
Topic: WRF-ROMS coupling
Replies: 2
Views: 4599

Re: WRF-ROMS coupling

John,

Please let us know when you set up another location to discuss model coupling. I know some people at my location who would definitely be interested and I'm sure there are many other people who are interested as well.

Patrick
by ptimko
Thu Aug 29, 2013 12:41 am
Forum: ROMS Documentation
Topic: how to prepare the zeta_east data using only two station?
Replies: 9
Views: 10035

Re: how to prepare the zeta_east data using only two station

Peter, Yes, that's the basic idea. If you want to force ROMS then you should use the correct input format for tidal forcing. If all you want is the data then you should be able to use TMD to predict the tidal heights at the boundary. I'm quite a patient guy (normally), glad I could help... :) Patrick
by ptimko
Wed Aug 28, 2013 3:24 am
Forum: ROMS Documentation
Topic: how to prepare the zeta_east data using only two station?
Replies: 9
Views: 10035

Re: how to prepare the zeta_east data using only two station

TMD will extract the tidal elevations and greenwich phase for the tidal constituents you want. It should also be able to make a prediction. Tidal forcing in ROMS is input in terms of the tidal elevations (amplitude and phase) as well as the tidal ellipses (semi-major axis, semi-minor axis, ellipse i...
by ptimko
Tue Aug 27, 2013 8:21 am
Forum: ROMS Documentation
Topic: how to prepare the zeta_east data using only two station?
Replies: 9
Views: 10035

Re: how to prepare the zeta_east data using only two station

You may want to review the documentation section on tidal forcing available on the ROMS website and also the "Packages" section for pre- and post-processing packages. There should be a section on tidal forcing if you follow the "Forcing Package" link. There is a TMD toolbox that ...
by ptimko
Wed Aug 21, 2013 12:40 am
Forum: ROMS Documentation
Topic: how to prepare the zeta_east data using only two station?
Replies: 9
Views: 10035

Re: how to prepare the zeta_east data using only two station

Depending on the total size of your domain have you consider using TPXO for the free surface boundary condition?
by ptimko
Thu Jul 04, 2013 1:50 am
Forum: ROMS Problems
Topic: Different upwelling results using different compilers
Replies: 8
Views: 5124

Re: Different upwelling results using different compilers

With regards to choosing the number of processors to use: You always want to make sure that the memory requirements for the job fit within the physical memory of the system you are using. On a stand alone machine you might as well compile the code under OMP (shared memory model); assuming of course ...
by ptimko
Wed Jul 03, 2013 2:27 am
Forum: ROMS Problems
Topic: Different upwelling results using different compilers
Replies: 8
Views: 5124

Re: Different upwelling results using different compilers

I'd say that Kate's best guess is correct since a 32 bit representation of a number is only accurate to about 7 decimal places.

I'm curious why you're getting a segmentation fault with -O3 on ifort; might want to try compiling with -traceback to see where the code breaks.
by ptimko
Sun Jun 16, 2013 12:41 am
Forum: ROMS Trivia
Topic: What´s the difference between Modeling and Simulating
Replies: 10
Views: 13293

Re: What´s the difference between Modeling and Simulating

Try this... A simulation is a recreation of a past event to examine what has happened in the past... Modelling is a study of the processes and forces involved to understand a physical or other other type of system... If you are only recreating the past from a single event I would say you are doing a...
by ptimko
Mon May 13, 2013 12:38 am
Forum: ROMS Discussion
Topic: Blowing up after 9966 timesteps
Replies: 7
Views: 3422

Re: Blowing up after 9966 timesteps

I'm also using the K-omega option. Not sure what else to suggest right now, if I think I'll let you know.
by ptimko
Sun May 12, 2013 12:46 am
Forum: ROMS Discussion
Topic: Blowing up after 9966 timesteps
Replies: 7
Views: 3422

Re: Blowing up after 9966 timesteps

You have what would appear to be a baroclinic instability. I would suggest checking you vertical mixing model. I have had problems in the past with ROMS by not specifying a vertical mixing model. The problem was solved by specifying a GLS mixing model in the model options during the build process. I...
by ptimko
Thu Oct 25, 2012 6:29 am
Forum: ROMS Usage
Topic: ROMS suitable for bottle-necked strongly stratified estuary?
Replies: 3
Views: 3731

Re: ROMS suitable for bottle-necked strongly stratified estu

I would think ROMS should be able to do this with few problems. About 10 years ago I was running a modified version of POM in an fjord that had near super-critical flow over a sill that had a coincident contraction. The horizontal resolution I used was 50 metres. I had 10 layers and depth range was ...
by ptimko
Thu Jul 19, 2012 12:29 pm
Forum: Job Opportunities
Topic: Fully Funded PhD Position at Bangor University, UK
Replies: 0
Views: 3843

Fully Funded PhD Position at Bangor University, UK

Category PhD Studentship Employer School of Ocean Sciences, Bangor University Location United Kingdom, Gwynedd, Bangor Closure Date Sunday, August 19, 2012 Description: For EU and UK students only Project title: Simulating the impacts of climate change on estuarine dynamics using an integrated catch...