mitgcm.core.Density Class Reference

A tracer point field that contains methods for density fields. More...

Inheritance diagram for mitgcm.core.Density:

Public Member Functions
def	__init__
def	calculate_density
	Cacluate Density field given temperature and salinity fields, using the linear equation of state. More...
def	calculate_TotRhoTend (self, model_instance)
	Calculate time rate of change of the Density field from the temperature tendency and the linear equation of state. More...
Public Member Functions inherited from mitgcm.core.Tracerpoint_field
def	__init__
def	load_field
	Load a model field from NetCDF output. More...
def	take_d_dx
	Take the x derivative of the field on tracer points, using spacings in grid object. More...
def	numerics_take_d_dx (self, rho, wet_mask_TH, dxC)
def	take_d_dy
	Take the y derivative of the field on tracer points, using spacings in grid object. More...
def	numerics_take_d_dy (self, rho, wet_mask_TH, dyC)
	The numerical bit of taking the y derivative. More...
def	take_d_dz
	Take the z derivative of the field given on tracer-points, using the spacings in grid object. More...
Public Member Functions inherited from mitgcm.core.MITgcm_Simulation
def	__init__
	Instantiate an MITgcm model instance. More...
def	load_field
	Load a model field from NetCDF output. More...
def	load_from_file (self, model_instance, file_list, variable, time_level, grid_loc, single_file)
	Internal function to pull the data from the file(s). More...
def	__add__ (self, other)
	A method that allows model objects to be added together. More...
def	__div__ (self, other)
	A method that allows model objects to be divided by floating point numbers. More...
def	__mul__ (self, other)
	A method that allows model objects to be multiplied by floating point numbers. More...
def	__rmul__ (self, other)
	A method that allows model objects to be multiplied by floating point numbers. More...

Additional Inherited Members
Public Attributes inherited from mitgcm.core.MITgcm_Simulation
	grid

Detailed Description

A tracer point field that contains methods for density fields.

Only linear equation of state with temperature variations is supported at the moment.

The linear equation of state is given by

\[ \rho = \rho_{nil} (-\alpha_{T} (\theta - \theta_{0}) + \beta_{S} (S - S_{0})) + \rho_{nil} \]

where \( \rho_{nil} \) is the reference density, \( \alpha_{T} \) is the thermal expansion coefficient, \( \beta_{S} \) is the haline contraction coefficient, \( \theta \) and \( \beta \) are the temperature and salinity fields, and subscript zeros denote reference values.

Definition at line 1028 of file core.py.

Constructor & Destructor Documentation

def mitgcm.core.Density.__init__	(		self,
			model_instance,
			Talpha = 2e-4,
			Sbeta = 0,
			RhoNil = 1035,
			cp = 4000,
			temp_field = 'THETA',
			salt_field = 'S',
			density_field = 'RHO',
			Tref = 20,
			Sref = 30,
			empty = False
	)

Definition at line 1041 of file core.py.

Member Function Documentation

def mitgcm.core.Density.calculate_density	(		self,
			model_instance,
			Talpha = 2e-4,
			Sbeta = 0,
			RhoNil = 1035,
			cp = 4000,
			temp_field = 'THETA',
			salt_field = 'S',
			density_field = 'RHO',
			Tref = 20,
			Sref = 30
	)

Cacluate Density field given temperature and salinity fields, using the linear equation of state.

Definition at line 1054 of file core.py.

def mitgcm.core.Density.calculate_TotRhoTend	(		self,
			model_instance
	)

Calculate time rate of change of the Density field from the temperature tendency and the linear equation of state.

Returned as 'TotRhoTend' associated with the density object.

Differentiating the linear equation of state with respect to temperature, and assuming \( \beta_{S} \) equals zero, gives

\[ \frac{\partial \rho}{\partial t} = - \rho_{nil} \alpha_{T} \frac{\partial \theta}{\partial t} \]

Definition at line 1067 of file core.py.

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The documentation for this class was generated from the following file:

• core.py