NEAR-SURFACE OCEAN THERMAL
STRUCTURE (NOTS)
LEARNING OBJECTIVES
Identify
applications, limitations, and assumptions of
the NOTS program. Interpret NOTS program
outputs.
The NOTS program is used to forecast changes in
the upper ocean thermal structure due to mixing by
surface winds, heating and cooling by surface heat,
precipitation, and evaporation. Program output consists
of profiles of temperature with respect to depth at
operator-specified forecast intervals; forecast profiles
may be run through the SSP program and then routed to
the OEF for use in various oceanographic and acoustic
programs.
APPLICATION
The NOTS program uses initial temperature
profiles and observed or forecasted surface
meteorological data to predict changes in the upper
ocean thermal structure with respect to time. The
forecast NOTS temperature profiles can be input to SSP
and then used by the RAY, PPL, and Sensor
Performance Prediction (SPP) programs to predict
acoustic propagation conditions and to predict
environmental effects on fleet ASW sensors and
operations.
LIMITATIONS AND ASSUMPTIONS
The restrictions as well as the principles taken for
granted in using the NOTS program areas follows:
. This program operates under the assumption that
oceanic conditions are horizontally homogeneous.
(Horizontal changes in the ocean thermal structure are
not considered.) This program should not be used in the
vicinity of strong currents, ocean fronts, or eddies.
l Since the quality of meteorological forecasts can
degrade significantly with respect to time, NOTS
forecasts more than 24 hours long should be used with
caution.
. The operator should use caution when specifying
cloud cover and precipitation rate information for a
given forecast time. The program linearly interpolates
these values for model forecast times between the
meteorological forecast times.
l This program should not be used for locations
over the continental shelf; neither should it be used near
regions of significant river runoff.
FUNCTIONAL DESCRIPTION
The NOTS model is used to forecast changes in the
upper ocean density structure due to mixing by surface
winds, heating and cooling by surface heat fluxes, and
evaporation and precipitation. Input to the model
consists of date, time, and position information; initial
temperature and salinity profiles; turbidity information;
and forecasts (or observations) of surface
meteorological conditions such as wind speed, wind
direction, air temperature, humidity, atmospheric
pressure, cloud cover, and precipitation rate. The date,
time, and position information, as well as the initial
temperature salinity profiles, are retrieved for the
operator-selected data set in the OEF. The surface
meteorological data are entered by the operator by way
of the keyboard.
Optical water-type (turbidity)
information for location of interest is retrieved from the
permanent data base (PDB) file.
Performing an upper ocean thermal structure
forecast involves three processing steps:
1. Initializing the model
2. Calculating surface fluxes
3. Using the model to calculate the effects
Output from the NOTS program consists of forecast
profiles of temperature with respect to depth for
operator-selected forecast times. These profiles are
routed to the NOTS forecast file. Operator-selected
forecast profiles are displayed, both in tabular and
graphical formats.
Output from this program is
classified and should be labeled as required.
SOUND SPEED PROFILE (SSP)
GENERATOR MODULE
LEARNING OBJECTIVES:
Identify
applications, limitations, and assumptions of
the SSP program.
Interpret SSP module
outputs.
The SSP generator module computes a sound speed
profile by applying Wilson’s equation for ocean sound
speed to a merged depth/temperature/salinity profile.
This creates a sound speed profile that represents local
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