While I'm no naval/sonar or programming expert, whether or not you are doing something stupid because you got convergence zones at 12 nm is difficult to say without knowing all settings you used (if I am allowed at all). I don't understand why you'd want to set 'surface bounce' to 0 though (which means it's off). That's an important part in (multiple) convergence zones. It needs reflection at the surface if all or most of the ray are to converge. Also I think the most important variable in soundray paths is the steepness in the speedgradient. Also the relative steepness of the different sections in the profile seem to make big differences in the path shapes according to my experimentations with the program. All I'm saying here is you left the juicy part out from your post.
I too noticed that this program doesn't accept fractional numbers well in the SSP. Atleast not real-life reasonable numbers. It seems to crash when speeds entered go above 99.7 m/s. But I allready emailed Dr.Sid privately (if he reads this: my real name is Rico) about this and he said he was working on a new version with some other improvements, to be expected soon. Also, all specified points in the profile get a zero speed gradient (the blue line is vertical at those circles) while everything in between is a smooth fit. This is not really compatible with the datapoints from the DW SSP profile table. In the SSP plot in DW there is a sharp crisp turn in the gradient at the layer. Only in the deep soundchannel section (convergence zone type) do the points indicate a smooth turn in the gradient. The DW SSP is very simple in shape btw, it's only made up of straight and parabolic (if convergence zone) gradient sections. I think I calculated some time ago that the true 0 speedchange depth of the deep soundchannel lies somewhere in between two specified depth points there. The minimum speed wasn't one of the points, but I'm not sure. And it would matter much. Dr.Sids program needs smooth curves everywhere (as he explained to me), so the local speed at depth is allways a bit off compared to what DW has (even if it didn't have round-off errors).
But you have to remember we are comparing apples and oranges here anyway. DW probably has a much more simplified sonar engine than this ray-tracer, if not radically different. There's no way this ray tracing could be done realtime in DW I think. But it's a great tool to get an idea of how those sound paths are created.
I would like to see from Dr.Sid if he can post a screendump of his program that shows some examples of sound paths he got with the SSP from DW in his tests. As far as the
SSP can be simulated ofcourse. Or atleast give us the datapoints in the SSP so we can try ourself.
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As for the signal levels .. what do you mean ?
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I think what GrayOwl is asking is what does the pixel intensity mean. Is it the summation of (fading out) amplitudes of all the passed rays through it. Or is it summed local soundpressure of each passing ray. (I hope you see the distinction I mean, I hardly do
) And/or is it in a linear or logarithmic scale. Which would make faint pixels way more fainter in terms of levels relative to source. I did notice that when the calculation an plotting is done the mouse can be used to look up decibel levels, which I have a hard time understanding in-and-of-itself, along the path. But it's not covered well inbetween the rays if the delta-rayangle is not fine enough. As you (Dr. Sid) allready know yourself.