Search found 11 matches

by saulo
Wed Jul 16, 2014 1:27 am
Forum: ROMS Problems
Topic: Near-bottom numerical instability over the slope
Replies: 16
Views: 5967

Re: Near-bottom numerical instability over the slope

Its best to close the boundaries to evaluate the error for sure. Looking back at some of your plots there seems to be a lot more activity near the boundaries than expected. For an application with no forcing and no horizontal variability in T/S you really don't have to worry about boundary reflectio...
by saulo
Fri Jul 11, 2014 10:37 pm
Forum: ROMS Problems
Topic: Near-bottom numerical instability over the slope
Replies: 16
Views: 5967

Re: Near-bottom numerical instability over the slope

The error decreased because I decreased rx1 alone. Actually my case was I had high vertical resolution, a large number of vertical levels and I would had to increase the horizontal resolution more than I could aford to bring rx1 down (so the reverse of what I said, sorry about that, it was a while a...
by saulo
Fri Jul 11, 2014 1:18 am
Forum: ROMS Problems
Topic: Near-bottom numerical instability over the slope
Replies: 16
Views: 5967

Re: Near-bottom numerical instability over the slope

The rx1 is a bit tricky as it seems application dependent. A value considered high may work on a given setup while a "low" value may not (a setup that depends largely on the topographical slope, which looks real steep in your case and the sharpness of gradients but also on the algorithms your choosi...
by saulo
Fri Apr 04, 2014 7:16 am
Forum: ROMS Discussion
Topic: Bulk fluxes, surface-relative winds and gustiness
Replies: 12
Views: 6184

Re: Bulk fluxes, surface-relative winds and gustiness

So ressurecting this thread... I just got revision 730. It seems Bulk_flux.F still does not take surface currents into account when computing stress. Is this correct? If so, are there other reasons for not including it (other than the reservations discussed above), such as of numerical design in nat...
by saulo
Sun Jul 14, 2013 12:53 am
Forum: ROMS Tools and Techniques
Topic: Problems on import octant
Replies: 2
Views: 1905

Re: Problems on import octant

Hi, You probably disrupted the python indentation when commenting a line of the grid.py, which if I remember is a necessary step on the instructions. Make sure all lines in this function are 4 columns from beguining of def statement. You can use an editor with automatic python indentation as well. M...
by saulo
Wed Oct 17, 2012 5:42 am
Forum: ROMS Bugs
Topic: regarding mixed layer depth and computation of transport
Replies: 5
Views: 3470

Re: regarding mixed layer depth and computation of transport

Hi, Hsbl is not the mixed layer. It's the boundary layer depth as defined in the KPP parametrization paper by Large et al 94. Basically some function of the surface forcing and density and momentum profile if I'm not mistaken. You can check that by comparing Hsbl with some MLD density difference cri...
by saulo
Sat Nov 12, 2011 3:03 am
Forum: ROMS Discussion
Topic: Confusion about Nudging Coefficient
Replies: 16
Views: 6550

Re: Confusion about Nudging Coefficient

From the code in ana_nudgecoef.h if you want to have just a relaxation boundary condition you must activate the option for climatological nudging (grid interior) such as TCLM_NUDGING, even if you don't want a widespread climatological nudging. So if I want to have a fairly strong nudging at the boun...
by saulo
Thu Nov 10, 2011 12:27 am
Forum: ROMS Problems
Topic: sponge layer for biharmonic viscosity
Replies: 4
Views: 2661

Re: sponge layer for biharmonic viscosity

Did you try and reduce the hyperviscosity coefficient? the rotation of biharmonic tensor induces large vertical fluxes that violate stability constraints (see Marchesiello et al. 2009). Clipping of hyperviscosity is needed in this case ... Thanks for the reply. I'm using for tracer advection the TS...
by saulo
Tue Nov 08, 2011 3:38 am
Forum: ROMS Problems
Topic: sponge layer for biharmonic viscosity
Replies: 4
Views: 2661

sponge layer for biharmonic viscosity

Dear all, I want to impose a sponge layer near my North and South wall boundaries. I have a resolution of dy ~= 4km, I decided that the layer will have 160km, so its size is 70 eta points. My VISC4 = 6d9 m^4s-1 (not even so sure how large or small this is, it was on some previous namelist) No grid d...
by saulo
Tue Mar 08, 2011 1:57 am
Forum: ROMS Problems
Topic: How to force the model after QuickScat?
Replies: 2
Views: 1596

Re: How to force the model after QuickScat?

Hi, You can try CCMP: http://podaac.jpl.nasa.gov/DATA_CATALOG/ccmpinfo.html Its not widely used as of yet. Not sure about quality, but its a blend of several satellite products and ECMWF forecasts. My comparisons to buoy are very favorable though. Note this is an analysis product. Also the time cove...
by saulo
Fri Mar 04, 2011 4:45 am
Forum: ROMS Usage
Topic: Partial use of bulk algorithm for surface fluxes in ROMS
Replies: 1
Views: 1183

Partial use of bulk algorithm for surface fluxes in ROMS

Dear forum, Can I use the bulk algorithm just to compute my momentum stresses and then set all the other fluxes to zero? I assume the COARE 3.0 bulk algo will only work with a specific meteorological input. Say I have all kinds of meteo data from a reanalysis for input to ROMS. But I only care about...