mom_tfreeze Module Reference

Detailed Description

Freezing point expressions.

Data Types
interface	calculate_tfreeze_linear
	Compute the freezing point potential temperature [degC] from salinity [ppt] and pressure [Pa] using a simple linear expression, with coefficients passed in as arguments. More...
interface	calculate_tfreeze_millero
	Compute the freezing point potential temperature [degC] from salinity [PSU] and pressure [Pa] using the expression from Millero (1978) (and in appendix A of Gill 1982), but with the of the pressure dependence changed from 7.53e-8 to 7.75e-8 to make this an expression for potential temperature (not in situ temperature), using a value that is correct at the freezing point at 35 PSU and 5e6 Pa (500 dbar). More...
interface	calculate_tfreeze_teos10
	Compute the freezing point conservative temperature [degC] from absolute salinity [g/kg] and pressure [Pa] using the TEOS10 package. More...

Functions/Subroutines
subroutine	calculate_tfreeze_linear_scalar (S, pres, T_Fr, TFr_S0_P0, dTFr_dS, dTFr_dp)
	This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using a simple linear expression, with coefficients passed in as arguments. More...
subroutine	calculate_tfreeze_linear_array (S, pres, T_Fr, start, npts, TFr_S0_P0, dTFr_dS, dTFr_dp)
	This subroutine computes an array of freezing point potential temperatures [degC] from salinity [ppt], and pressure [Pa] using a simple linear expression, with coefficients passed in as arguments. More...
subroutine	calculate_tfreeze_millero_scalar (S, pres, T_Fr)
	This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using the expression from Millero (1978) (and in appendix A of Gill 1982), but with the of the pressure dependence changed from 7.53e-8 to 7.75e-8 to make this an expression for potential temperature (not in situ temperature), using a value that is correct at the freezing point at 35 PSU and 5e6 Pa (500 dbar). More...
subroutine	calculate_tfreeze_millero_array (S, pres, T_Fr, start, npts)
	This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using the expression from Millero (1978) (and in appendix A of Gill 1982), but with the of the pressure dependence changed from 7.53e-8 to 7.75e-8 to make this an expression for potential temperature (not in situ temperature), using a value that is correct at the freezing point at 35 PSU and 5e6 Pa (500 dbar). More...
subroutine	calculate_tfreeze_teos10_scalar (S, pres, T_Fr)
	This subroutine computes the freezing point conservative temperature [degC] from absolute salinity [g/kg], and pressure [Pa] using the TEOS10 package. More...
subroutine	calculate_tfreeze_teos10_array (S, pres, T_Fr, start, npts)
	This subroutine computes the freezing point conservative temperature [degC] from absolute salinity [g/kg], and pressure [Pa] using the TEOS10 package. More...

Function/Subroutine Documentation

calculate_tfreeze_linear_array()

subroutine mom_tfreeze::calculate_tfreeze_linear_array ( real, dimension(:), intent(in)  S, real, dimension(:), intent(in)  pres, real, dimension(:), intent(out)  T_Fr, integer, intent(in)  start, integer, intent(in)  npts, real, intent(in)  TFr_S0_P0, real, intent(in)  dTFr_dS, real, intent(in)  dTFr_dp  )

private

This subroutine computes an array of freezing point potential temperatures [degC] from salinity [ppt], and pressure [Pa] using a simple linear expression, with coefficients passed in as arguments.

Parameters

[in]	s	salinity [ppt].
[in]	pres	pressure [Pa].
[out]	t_fr	Freezing point potential temperature [degC].
[in]	start	the starting point in the arrays.
[in]	npts	the number of values to calculate.
[in]	tfr_s0_p0	The freezing point at S=0, p=0, [degC].
[in]	dtfr_ds	The derivative of freezing point with salinity, [degC PSU-1].
[in]	dtfr_dp	The derivative of freezing point with pressure, [degC Pa-1].

Definition at line 62 of file MOM_TFreeze.F90.

  real,  dimension(:), intent(in)  :: S         !< salinity [ppt].
  real,  dimension(:), intent(in)  :: pres      !< pressure [Pa].
  real,  dimension(:), intent(out) :: T_Fr      !< Freezing point potential temperature [degC].
  integer,             intent(in)  :: start     !< the starting point in the arrays.
  integer,             intent(in)  :: npts      !< the number of values to calculate.
  real,                intent(in)  :: TFr_S0_P0 !< The freezing point at S=0, p=0, [degC].
  real,                intent(in)  :: dTFr_dS   !< The derivative of freezing point with salinity,
                                                !! [degC PSU-1].
  real,                intent(in)  :: dTFr_dp   !< The derivative of freezing point with pressure,
                                                !! [degC Pa-1].
  integer :: j
 
  do j=start,start+npts-1
    t_fr(j) = (tfr_s0_p0 + dtfr_ds*s(j)) + dtfr_dp*pres(j)
  enddo
 

calculate_tfreeze_linear_scalar()

subroutine mom_tfreeze::calculate_tfreeze_linear_scalar ( real, intent(in)  S, real, intent(in)  pres, real, intent(out)  T_Fr, real, intent(in)  TFr_S0_P0, real, intent(in)  dTFr_dS, real, intent(in)  dTFr_dp  )

private

This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using a simple linear expression, with coefficients passed in as arguments.

Parameters

[in]	s	salinity [ppt].
[in]	pres	pressure [Pa].
[out]	t_fr	Freezing point potential temperature [degC].
[in]	tfr_s0_p0	The freezing point at S=0, p=0 [degC].
[in]	dtfr_ds	The derivative of freezing point with salinity, [degC ppt-1].
[in]	dtfr_dp	The derivative of freezing point with pressure, [degC Pa-1].

Definition at line 44 of file MOM_TFreeze.F90.

  real,  intent(in)  :: S         !< salinity [ppt].
  real,  intent(in)  :: pres      !< pressure [Pa].
  real,  intent(out) :: T_Fr      !< Freezing point potential temperature [degC].
  real,  intent(in)  :: TFr_S0_P0 !< The freezing point at S=0, p=0 [degC].
  real,  intent(in)  :: dTFr_dS   !< The derivative of freezing point with salinity,
                                  !! [degC ppt-1].
  real,  intent(in)  :: dTFr_dp   !< The derivative of freezing point with pressure,
                                  !! [degC Pa-1].
 
  t_fr = (tfr_s0_p0 + dtfr_ds*s) + dtfr_dp*pres
 

calculate_tfreeze_millero_array()

subroutine mom_tfreeze::calculate_tfreeze_millero_array ( real, dimension(:), intent(in)  S, real, dimension(:), intent(in)  pres, real, dimension(:), intent(out)  T_Fr, integer, intent(in)  start, integer, intent(in)  npts  )

private

This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using the expression from Millero (1978) (and in appendix A of Gill 1982), but with the of the pressure dependence changed from 7.53e-8 to 7.75e-8 to make this an expression for potential temperature (not in situ temperature), using a value that is correct at the freezing point at 35 PSU and 5e6 Pa (500 dbar).

Parameters

[in]	s	Salinity [PSU].
[in]	pres	Pressure [Pa].
[out]	t_fr	Freezing point potential temperature [degC].
[in]	start	The starting point in the arrays.
[in]	npts	The number of values to calculate.

Definition at line 106 of file MOM_TFreeze.F90.

  real,  dimension(:), intent(in)  :: S     !< Salinity [PSU].
  real,  dimension(:), intent(in)  :: pres  !< Pressure [Pa].
  real,  dimension(:), intent(out) :: T_Fr  !< Freezing point potential temperature [degC].
  integer,             intent(in)  :: start !< The starting point in the arrays.
  integer,             intent(in)  :: npts  !< The number of values to calculate.
 
  ! Local variables
  real, parameter :: cS1 = -0.0575, cs3_2 = 1.710523e-3, cs2 = -2.154996e-4
  real, parameter :: dTFr_dp = -7.75e-8
  integer :: j
 
  do j=start,start+npts-1
    t_fr(j) = s(j)*(cs1 + (cs3_2 * sqrt(max(s(j),0.0)) + cs2 * s(j))) + &
              dtfr_dp*pres(j)
  enddo
 

calculate_tfreeze_millero_scalar()

subroutine mom_tfreeze::calculate_tfreeze_millero_scalar ( real, intent(in)  S, real, intent(in)  pres, real, intent(out)  T_Fr  )

private

This subroutine computes the freezing point potential temperature [degC] from salinity [ppt], and pressure [Pa] using the expression from Millero (1978) (and in appendix A of Gill 1982), but with the of the pressure dependence changed from 7.53e-8 to 7.75e-8 to make this an expression for potential temperature (not in situ temperature), using a value that is correct at the freezing point at 35 PSU and 5e6 Pa (500 dbar).

Parameters

[in]	s	Salinity in PSU.
[in]	pres	Pressure [Pa].
[out]	t_fr	Freezing point potential temperature [degC].

Definition at line 87 of file MOM_TFreeze.F90.

  real,    intent(in)  :: S    !< Salinity in PSU.
  real,    intent(in)  :: pres !< Pressure [Pa].
  real,    intent(out) :: T_Fr !< Freezing point potential temperature [degC].
 
  ! Local variables
  real, parameter :: cS1 = -0.0575, cs3_2 = 1.710523e-3, cs2 = -2.154996e-4
  real, parameter :: dTFr_dp = -7.75e-8
 
  t_fr = s*(cs1 + (cs3_2 * sqrt(max(s,0.0)) + cs2 * s)) + dtfr_dp*pres
 

calculate_tfreeze_teos10_array()

subroutine mom_tfreeze::calculate_tfreeze_teos10_array ( real, dimension(:), intent(in)  S, real, dimension(:), intent(in)  pres, real, dimension(:), intent(out)  T_Fr, integer, intent(in)  start, integer, intent(in)  npts  )

private

This subroutine computes the freezing point conservative temperature [degC] from absolute salinity [g/kg], and pressure [Pa] using the TEOS10 package.

Parameters

[in]	s	absolute salinity [g/kg].
[in]	pres	pressure [Pa].
[out]	t_fr	Freezing point conservative temperature [degC].
[in]	start	the starting point in the arrays.
[in]	npts	the number of values to calculate.

Definition at line 148 of file MOM_TFreeze.F90.

  real, dimension(:), intent(in)  :: S     !< absolute salinity [g/kg].
  real, dimension(:), intent(in)  :: pres  !< pressure [Pa].
  real, dimension(:), intent(out) :: T_Fr  !< Freezing point conservative temperature [degC].
  integer,            intent(in)  :: start !< the starting point in the arrays.
  integer,            intent(in)  :: npts  !< the number of values to calculate.
 
  ! Local variables
  real, parameter :: Pa2db  = 1.e-4  ! The conversion factor from Pa to dbar.
  real :: zs,zp
  integer :: j
  ! Assume sea-water contains no dissolved air.
  real, parameter :: saturation_fraction = 0.0
 
  do j=start,start+npts-1
    !Conversions
    zs = s(j)
    zp = pres(j)* pa2db         !Convert pressure from Pascal to decibar
 
    if (s(j) < -1.0e-10) cycle !Can we assume safely that this is a missing value?
    t_fr(j) = gsw_ct_freezing_exact(zs,zp,saturation_fraction)
 enddo
 

Referenced by calculate_tfreeze_teos10_scalar().

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calculate_tfreeze_teos10_scalar()

subroutine mom_tfreeze::calculate_tfreeze_teos10_scalar ( real, intent(in)  S, real, intent(in)  pres, real, intent(out)  T_Fr  )

private

This subroutine computes the freezing point conservative temperature [degC] from absolute salinity [g/kg], and pressure [Pa] using the TEOS10 package.

Parameters

[in]	s	Absolute salinity [g/kg].
[in]	pres	Pressure [Pa].
[out]	t_fr	Freezing point conservative temperature [degC].

Definition at line 128 of file MOM_TFreeze.F90.

  real,    intent(in)  :: S    !< Absolute salinity [g/kg].
  real,    intent(in)  :: pres !< Pressure [Pa].
  real,    intent(out) :: T_Fr !< Freezing point conservative temperature [degC].
 
  ! Local variables
  real, dimension(1) :: S0, pres0
  real, dimension(1) :: tfr0
 
  s0(1) = s
  pres0(1) = pres
 
  call calculate_tfreeze_teos10_array(s0, pres0, tfr0, 1, 1)
  t_fr = tfr0(1)
 

References calculate_tfreeze_teos10_array().

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