oceanic conditions. The output generated by the SSP
generator module is a sound speed vs. depth profile from
the sea surface to the ocean bottom, which is essential
in making accurate sensor range predictions.
The SSP module yields tactically useful information
when a basic knowledge of underwater acoustics is
applied to the products. This information can be used
to make decisions regarding sensor depth settings,
optimum frequency bands for search, and buoy pattern.
By examining the sound speed profile and other module
output, the experienced ASW technician can learn a
great deal about available acoustic transmission paths
and sensor performance.
The optimum frequency for detection in the sonic
layer may be determined from the sonic layer cutoff
frequency calculated by SSP. The presence, quality, and
accessibility of a sound channel to available sensors can
be identified from the generated sound speed profile.
CZs may exist where the sound speed at the bottom
exceeds the sound speed at the source depth, providing
there is an experienced analyst with a means to estimate
CZ range and width from the shape of the sound speed
LIMITATIONS AND ASSUMPTIONS
The restrictions as well as the principles taken for
granted in using the SSP product areas follows:
l SSP allows the operator to review and correct
manual input. This prevents aborting runs due to
The SSP merging routine combines BT data with a
historical profile to form a surface-to-bottom
temperature/salinity profile. The resulting merged
profile consists of the BT data in the upper portion and
the historical profile, modified by the merge, in the
lower portion. The lower portion extends from the first
depth value below the available BT data to the bottom
depth. Output from this program is classified and
should be labeled as required.
The first portion of this chapter was devoted to
computer aids generated by the TESS 3 configuration.
Now lets look at the BT collective product.
applications, limitations, and assumptions of
the bathythermograph collective product.
FLENUMMETOCCEN is capable of providing
synoptic (real-time) and historical bathythermograph
(BATHY) observation collectives for a specified area
and timeframe. Pre-1985 BATHYs are stored in the
Master Oceanographic Observation Data Set (MOODS)
with over 4.6 million observations. More recent
BATHYs, which have not yet been added to the
MOODS data base are stored in a separate archive in a
format called 4D. The last 12 hours of BATHYs are
stored on the operational computers. Output from this
program is classified and should be labeled as required.
. In deep-water areas, on-scene bathythermograph
(BT) data that do not extend below 200 m should be used
l Where no historical profile data are available,
operator entry of surface-to-bottom depth/
temperature/salinity sound speed values is required.
The SSP module provides the operator with a sound
speed profile that is representative of local oceanic
conditions. This module also provides a link between
environmental variability and sonar performance. An
on-scene BT and a historical depth/temperature/salinity
profile are used to compute the sound speed profile and
The BATHY collective product provides a
convenient means for an activity or unit to retrieve
historical data and/or receive synoptic data for a specific
area/time period. The product can be used for onboard
prediction systems or for exercise planning/
LIMITATIONS AND ASSUMPTIONS
The synoptic BATHY collective is a simple and
easily transmittable product that provides detailed