Ocean Modeling Discussion

Hi: Thank you for your valuable comments and document. of the velocity field to du/dz = sustr/Akv at the free surface. This is the only natural physical boundary condition, provided that (1) Akv remains finite at surface; and (2) the vertical profile of u (Ekman spiral or whatever) is adequately res...

Hi: I have a question about the spline interpolation used to get the stress by the vertical viscosity in step3d_uv.F. I guess that derivatives at the boundary (or alternatives) should be prescribed in the spline interpolation. What kind of the boundary condition is assumed in ROMS? It seems to me th...

Just for your information, equations with a biharmonic term (which is used for mix4... option) e.g. p_t = -p_xxxx with p=delta(x) at t=0 do have negative solutions. Such features of the biharmonic term are quite different from those of the harmonic term (e.g. Pedlosky & Chapman 1993, JPO and rel...

This is not a direct answer but I wonder if this may be some hint for someone else. How does the commercial Intel Fortran compiler use CPUs? In my understanding one Xeon processor has two CPUs in it (is this correct?). In our HITACHI's machine which is an extreme example 1x1 tiling always gives the ...

Thank you Mark. I learned another new thing. What is regarded as a bad example of programing in Fortran 77 is not so in Fortran 90. If I change the 2D kernel program of ROMS2x so that it uses older technique for work arrays, I may be able to get better performance in HITACHI's compiler. Let me try t...

I just got back from other works. Thank you for your comments, Mark. I learned a lot of new things about ROMS 2x. I tried BENCHMARK1 instead of UPWELLING. I got results which are different from those for UPWELLING examples. For BENCHMARK1, ROMS2.1 is about 1.3 times faster than 1.8 on our HITACHI's ...

Thank you Mark. Now I have totally understood what you wrote on Nov 3, 2004. I changed "define ASSUMED_SHAPE" in globaldefs.h to "undef ASSUMED_SHAPE". However, ROMS slowed down more... I compared ROMS1.8 and 2.1 using UPWELLING example. Since cppdefs.h of this example is not exa...

Hi. I remember what Mark Hadfield wrote long time ago related with benchmark tests. ROMS2.x can be much slower than 1.8 on some "old" compilers due to implicit-shape of dummy arguments in 2.x. I am still encountering this problem and using 1.8 for my research. The compiler that I am using ...