Pressure Density

R2026b

Compute sea pressure and in situ density of seawater from depth, temperature, and salinity

Since R2026b

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Pressure Density block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Aerospace Blockset Maritime Applications Library / Environment

Description

Add-On Required: This feature requires the Aerospace Blockset Maritime Applications Library add-on.

The Pressure Density block computes seawater pressure and density from depth, in-situ temperature, and practical salinity using the Thermodynamic Equation of Seawater 2010 (TEOS-10) international standard. The block can also accept latitude and longitude inputs to account for the geographic correction of the absolute salinity anomaly.

Block outputs are valid within the TEOS-10 oceanographic funnel (with a depth of 0 to 5500 m, temperature of -2 to 40 °C, and practical salinity 0 to 42). The block excludes Baltic Sea, inland seas, and special region corrections.

Ports

Input

depth — Depth below surface

scalar between 0 and 5500 m, inclusive

Depth below surface in the ocean, specified as a scalar value between 0 and 5500 m, inclusive. The block uses depth to compute local in‑situ seawater properties, in the units specified in Units.

Data Types: double

t_in-situ — Measured in-situ temperature

scalar between -2 and 40 degrees Celsius, inclusive

Measured in-situ temperature, specified as a scalar value between -2 and 40 degrees Celsius, inclusive, in the units specified in Units.

Data Types: double

S_P — Practical salinity

scalar value between 0 and 42

Practical salinity (PSS-78), specified as a scalar value between 0 and 42. This value is unitless.

Data Types: double

μ — Latitude

scalar between -90 and 90 deg, inclusive

Latitude for gravity-dependent pressure calculation and absolute salinity anomaly correction, specified as a scalar value between -90 and 90 deg, inclusive. The block wraps out-of-range values before evaluation.

Dependencies

To enable this port, select the Input for salinity anomaly parameter.

Data Types: double

l — Longitude

scalar between -180 and 180 deg, inclusive

Longitude for salinity correction, specified as a scalar value between -180 and 180 deg, inclusive. The block wraps out-of-range values before evaluation.

Dependencies

To enable this port, select the Input for salinity anomaly parameter.

Data Types: double

Output

p_sea — Sea pressure

scalar

Sea pressure, returned as a scalar in Pa or psf, in the units specified in Units.

Data Types: double

ρ — In-situ seawater density

scalar

In-situ seawater density, returned as a scalar in the units specified in Units.

Data Types: double

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Units — Parameter and port units

Metric (MKS) (default) | English

Parameter and port units, specified as one of these values:

Units	Depth	Temperature	Pressure	Density
Metric (MKS)	meters	degrees Celsius (°C)	Pa	kg/m3
English	feet	degrees Fahrenheit (°F)	psf	slug/ft3

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	units
Values:	Metric (MKS) (default) | English

Example: set_param(gcb,"units","Metric (MKS)")

Action for out-of-range input — Out-of-range block behavior

Error (default) | Warning | None

Out-of-range block behavior, specified as one of these values:

Action	Description
None	NaNs are returned.
Warning	Warning in the Diagnostic Viewer. Model simulation continues.
Error (default)	Error in the Diagnostic Viewer. Model simulation stops.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	action
Values:	Error (default) | Warning | None

Example: set_param(gcb,"action","Warning")

Input for salinity anomaly — Option to use geographic corrections

off (default) | on

To enable the use of geographic corrections for salinity anomalies, select this parameter. Otherwise, clear this parameter. When this parameter is cleared, the block omits geographic salinity anomaly correction and uses a latitude of 0 degrees for the depth-to-pressure conversion.

When this parameter is cleared, the block uses latitude 0° and longitude 0° for both the depth-to-pressure conversion and the absolute-salinity computation. This is equivalent to the reference-composition relation (no regional δSA correction).

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

To get the block parameter value programmatically, use the get_param function.

Parameter:	deltaSa
Values:	off (default) | on

Example: set_param(gcb,"deltaSa","on")

References

[1] Intergovernmental Oceanographic Commission, Manuals and Guides No. 56. The International Thermodynamic Equation of Seawater - 2010: Calculation and Use of Thermodynamic Properties. SCOR, IAPSO, and UNESCO, 2010. https://www.teos-10.org/pubs/TEOS-10_Manual.pdf.

Version History

Introduced in R2026b