SSP types description

[Delareon]

Hey folks,
im searching for a description about the different SSP types.
Something like that from the ASW Training Mission from Molon Labe:

A surface duct means that you will get very long detection ranges when you and a contact are above the layer, comparatively short detection ranges for when you and a contact are below the layer, and very short detection ranges for when you and the contact are on opposite sides of the layer.

Can someone point me to the right direction?