Arctic Sound Speed Profiles

[SeaQueen]

In my Kara Sea scenario, as I've been honing it, I've been faced with a dilema. DW lacks a truely satisfactory SSP for arctic scenarios.

Arctic waters are nearly isothermal, so at first I elected to use the "Surface Duct" SSP. I hoped the game engine would treat it as a big mixed layer, essentially. Unfortunately, that proved to be a bad idea because even in shallow water, occaisionally, a sonic layer would appear, undermining the essential characteristic of arctic waters - there is no thermocline.

So... I'm left with the "Bottom Limited" SSP, which will increase the speed of sound uniformly to the bottom. It doesn't sit well with me for other reasons, though.

Do any fellow sonar geeks out there have any thoughts about what the best compromise is?

[Bellman]

Sure getting some surprising effects near the surface. :hmm:

[Kapitan]

As a veteran of under ice missions i say this,

Try not to go near the kara sea its very shallow and the ice is unpredictable and you can easily get stuck.
if you do venture into the Kara sea stay at least 45 to 55 miles from the land (main land russia) or follow novaya zemlya.

In the kara sea the ambient noise should be higher, and the layer depths should change alot and rapidly, personaly finding a contact here is like trying to hit a basketball with a shoe horn.

Any mission i made that i had to go near the kara sea id always follow the same principles;

1) check the HF sonar ever few minuets
2) check normal sonar (dont extend TA gets broken easily)
3) never go too deep or fast.

Average water temp for Kara sea is about -3*c dropping the further you go north and down, you realy strugle to find your way through this area and it can be frustrating, i downloaded a map of the artic area and i used to double check with that and the nav screen to see if all was ok (sometimes nav map was wrong)

As for a termocline no there isnt one but there are layer depths in some parts (around iceland and greenland and the svalbard).

Best way to find contacts in this area is to use sphere sonar your hull array will be washed out and towed wont function properly because it probly be dragging on the ground even at 4 knots.

Note this is for Akula diver experiance

[Bill Nichols]

Originally Posted by SeaQueen

In my Kara Sea scenario, as I've been honing it, I've been faced with a dilema. DW lacks a truely satisfactory SSP for arctic scenarios.

Arctic waters are nearly isothermal, so at first I elected to use the "Surface Duct" SSP. I hoped the game engine would treat it as a big mixed layer, essentially. Unfortunately, that proved to be a bad idea because even in shallow water, occaisionally, a sonic layer would appear, undermining the essential characteristic of arctic waters - there is no thermocline.

So... I'm left with the "Bottom Limited" SSP, which will increase the speed of sound uniformly to the bottom. It doesn't sit well with me for other reasons, though.

Do any fellow sonar geeks out there have any thoughts about what the best compromise is?

In actuality, if temperature remains constant then speed will increase with depth, due to the compressibility of water at higher pressures. Granted, it's not a strong function, but in deep water it's important (it's why convergence zones exist).

[SeaQueen]

Originally Posted by Bill Nichols

In actuality, if temperature remains constant then speed will increase with depth, due to the compressibility of water at higher pressures. Granted, it's not a strong function, but in deep water it's important (it's why convergence zones exist).

Right... and that's what I'm trying to get it to do. I'm saying that DW doesn't have a good way to represent an isothermal situation. Their "Surface Duct" environment leaves you with a thermocline, hence it's not isothermal, but their "Bottom Limited" SSP (which isn't really bottom limited because in DW the sound speed increases linearly all the way to the bottom), doesn't sit well with me because I'm scared that when (if?) they fix it, I'll have to redo the scenario to make it work right, so I'm not sure what a good compromise is.

[Kapitan]

Just played the Kara sea search and posted my thoughts in the review