Ice

Functions about ice and melting, but not the freezing point.

gsw.ice.Helmholtz_energy_ice(t, p)

Calculates the Helmholtz energy of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

Helmholtz_energy_icearray-like, J/kg

Helmholtz energy of ice

gsw.ice.adiabatic_lapse_rate_ice(t, p)

Calculates the adiabatic lapse rate of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

adiabatic_lapse_rate_icearray-like, K/Pa

adiabatic lapse rate

gsw.ice.alpha_wrt_t_ice(t, p)

Calculates the thermal expansion coefficient of ice with respect to in-situ temperature.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

alpha_wrt_t_icearray-like, 1/K

thermal expansion coefficient of ice with respect to in-situ temperature

gsw.ice.chem_potential_water_ice(t, p)

Calculates the chemical potential of water in ice from in-situ temperature and pressure.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

chem_potential_water_icearray-like, J/kg

chemical potential of ice

gsw.ice.cp_ice(t, p)

Calculates the isobaric heat capacity of seawater.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

cp_icearray-like, J kg^-1 K^-1

heat capacity of ice

gsw.ice.enthalpy_ice(t, p)

Calculates the specific enthalpy of ice (h_Ih).

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

enthalpy_icearray-like, J/kg

specific enthalpy of ice

gsw.ice.entropy_ice(t, p)

Calculates specific entropy of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

ice_entropyarray-like, J kg^-1 K^-1

specific entropy of ice

gsw.ice.ice_fraction_to_freeze_seawater(SA, CT, p, t_Ih)

Calculates the mass fraction of ice (mass of ice divided by mass of ice plus seawater), which, when melted into seawater having (SA,CT,p) causes the final dilute seawater to be at the freezing temperature. The other outputs are the Absolute Salinity and Conservative Temperature of the final diluted seawater.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

t_Iharray-like

In-situ temperature of ice (ITS-90), degrees C

Returns

SA_freezearray-like, g/kg

Absolute Salinity of seawater after the mass fraction of ice, ice_fraction, at temperature t_Ih has melted into the original seawater, and the final mixture is at the freezing temperature of seawater.

CT_freezearray-like, deg C

Conservative Temperature of seawater after the mass fraction, w_Ih, of ice at temperature t_Ih has melted into the original seawater, and the final mixture is at the freezing temperature of seawater.

w_Iharray-like, unitless

mass fraction of ice, having in-situ temperature t_Ih, which, when melted into seawater at (SA,CT,p) leads to the final diluted seawater being at the freezing temperature. This output must be between 0 and 1.

gsw.ice.internal_energy_ice(t, p)

Calculates the specific internal energy of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

internal_energy_icearray-like, J/kg

specific internal energy (u)

gsw.ice.kappa_const_t_ice(t, p)

Calculates isothermal compressibility of ice. Note. This is the compressibility of ice AT CONSTANT IN-SITU TEMPERATURE

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

kappa_const_t_icearray-like, 1/Pa

isothermal compressibility

gsw.ice.kappa_ice(t, p)

Calculates the isentropic compressibility of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

kappa_icearray-like, 1/Pa

isentropic compressibility

gsw.ice.melting_ice_SA_CT_ratio(SA, CT, p, t_Ih)

Calculates the ratio of SA to CT changes when ice melts into seawater. It is assumed that a small mass of ice melts into an infinite mass of seawater. Because of the infinite mass of seawater, the ice will always melt.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

t_Iharray-like

In-situ temperature of ice (ITS-90), degrees C

Returns

melting_ice_SA_CT_ratioarray-like, g kg^-1 K^-1

the ratio of SA to CT changes when ice melts into a large mass of seawater

gsw.ice.melting_ice_SA_CT_ratio_poly(SA, CT, p, t_Ih)

Calculates the ratio of SA to CT changes when ice melts into seawater. It is assumed that a small mass of ice melts into an infinite mass of seawater. Because of the infinite mass of seawater, the ice will always melt.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

t_Iharray-like

In-situ temperature of ice (ITS-90), degrees C

Returns

melting_ice_SA_CT_ratioarray-like, g kg^-1 K^-1

the ratio of SA to CT changes when ice melts into a large mass of seawater

gsw.ice.melting_ice_equilibrium_SA_CT_ratio(SA, p)

Calculates the ratio of SA to CT changes when ice melts into seawater with both the seawater and the seaice temperatures being almost equal to the equilibrium freezing temperature. It is assumed that a small mass of ice melts into an infinite mass of seawater. If indeed the temperature of the seawater and the ice were both equal to the freezing temperature, then no melting or freezing would occur; an imbalance between these three temperatures is needed for freezing or melting to occur (the three temperatures being (1) the seawater temperature, (2) the ice temperature, and (3) the freezing temperature.

Parameters

SAarray-like

Absolute Salinity, g/kg

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

melting_ice_equilibrium_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when ice melts into seawater, with the seawater and seaice being close to the freezing temperature.

gsw.ice.melting_ice_equilibrium_SA_CT_ratio_poly(SA, p)

Calculates the ratio of SA to CT changes when ice melts into seawater with both the seawater and the seaice temperatures being almost equal to the equilibrium freezing temperature. It is assumed that a small mass of ice melts into an infinite mass of seawater. If indeed the temperature of the seawater and the ice were both equal to the freezing temperature, then no melting or freezing would occur; an imbalance between these three temperatures is needed for freezing or melting to occur (the three temperatures being (1) the seawater temperature, (2) the ice temperature, and (3) the freezing temperature.

Parameters

SAarray-like

Absolute Salinity, g/kg

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

melting_ice_equilibrium_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when ice melts into seawater, with the seawater and seaice being close to the freezing temperature.

gsw.ice.melting_ice_into_seawater(SA, CT, p, w_Ih, t_Ih)

Calculates the final Absolute Salinity, final Conservative Temperature and final ice mass fraction that results when a given mass fraction of ice melts and is mixed into seawater whose properties are (SA,CT,p). This code takes the seawater to contain no dissolved air.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

w_Iharray-like

mass fraction of ice: the mass of ice divided by the sum of the masses of ice and seawater. 0 <= wIh <= 1. unitless.

t_Iharray-like

In-situ temperature of ice (ITS-90), degrees C

Returns

SA_finalarray-like, g/kg

Absolute Salinity of the seawater in the final state, whether or not any ice is present.

CT_finalarray-like, deg C

Conservative Temperature of the seawater in the final state, whether or not any ice is present.

w_Ih_finalarray-like, unitless

mass fraction of ice in the final seawater-ice mixture. If this ice mass fraction is positive, the system is at thermodynamic equilibrium. If this ice mass fraction is zero there is no ice in the final state which consists only of seawater which is warmer than the freezing temperature.

gsw.ice.melting_seaice_SA_CT_ratio(SA, CT, p, SA_seaice, t_seaice)

Calculates the ratio of SA to CT changes when sea ice melts into seawater. It is assumed that a small mass of sea ice melts into an infinite mass of seawater. Because of the infinite mass of seawater, the sea ice will always melt.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

SA_seaicearray-like

Absolute Salinity of sea ice: the mass fraction of salt in sea ice, expressed in g of salt per kg of sea ice.

t_seaicearray-like

In-situ temperature of the sea ice at pressure p (ITS-90), degrees C

Returns

melting_seaice_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when sea ice melts into a large mass of seawater

gsw.ice.melting_seaice_SA_CT_ratio_poly(SA, CT, p, SA_seaice, t_seaice)

Calculates the ratio of SA to CT changes when sea ice melts into seawater. It is assumed that a small mass of sea ice melts into an infinite mass of seawater. Because of the infinite mass of seawater, the sea ice will always melt.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

SA_seaicearray-like

Absolute Salinity of sea ice: the mass fraction of salt in sea ice, expressed in g of salt per kg of sea ice.

t_seaicearray-like

In-situ temperature of the sea ice at pressure p (ITS-90), degrees C

Returns

melting_seaice_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when sea ice melts into a large mass of seawater

gsw.ice.melting_seaice_equilibrium_SA_CT_ratio(SA, p)

Calculates the ratio of SA to CT changes when sea ice melts into seawater with both the seawater and the sea ice temperatures being almost equal to the equilibrium freezing temperature. It is assumed that a small mass of seaice melts into an infinite mass of seawater. If indeed the temperature of the seawater and the sea ice were both equal to the freezing temperature, then no melting or freezing would occur; an imbalance between these three temperatures is needed for freezing or melting to occur (the three temperatures being (1) the seawater temperature, (2) the sea ice temperature, and (3) the freezing temperature.

Parameters

SAarray-like

Absolute Salinity, g/kg

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

melting_seaice_equilibrium_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when sea ice melts into seawater, with the seawater and sea ice being close to the freezing temperature.

gsw.ice.melting_seaice_equilibrium_SA_CT_ratio_poly(SA, p)

Calculates the ratio of SA to CT changes when sea ice melts into seawater with both the seawater and the sea ice temperatures being almost equal to the equilibrium freezing temperature. It is assumed that a small mass of seaice melts into an infinite mass of seawater. If indeed the temperature of the seawater and the sea ice were both equal to the freezing temperature, then no melting or freezing would occur; an imbalance between these three temperatures is needed for freezing or melting to occur (the three temperatures being (1) the seawater temperature, (2) the sea ice temperature, and (3) the freezing temperature.

Parameters

SAarray-like

Absolute Salinity, g/kg

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

melting_seaice_equilibrium_SA_CT_ratioarray-like, g/(kg K)

the ratio dSA/dCT of SA to CT changes when sea ice melts into seawater, with the seawater and sea ice being close to the freezing temperature.

gsw.ice.melting_seaice_into_seawater(SA, CT, p, w_seaice, SA_seaice, t_seaice)

Calculates the Absolute Salinity and Conservative Temperature that results when a given mass of sea ice (or ice) melts and is mixed into a known mass of seawater (whose properties are (SA,CT,p)).

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

w_seaicearray-like

mass fraction of ice: the mass of sea-ice divided by the sum of the masses of sea-ice and seawater. 0 <= wIh <= 1. unitless.

SA_seaicearray-like

Absolute Salinity of sea ice: the mass fraction of salt in sea ice, expressed in g of salt per kg of sea ice.

t_seaicearray-like

In-situ temperature of the sea ice at pressure p (ITS-90), degrees C

Returns

SA_finalarray-like, g/kg

Absolute Salinity of the mixture of the melted sea ice (or ice) and the original seawater

CT_finalarray-like, deg C

Conservative Temperature of the mixture of the melted sea ice (or ice) and the original seawater

gsw.ice.pot_enthalpy_from_pt_ice(pt0_ice)

Calculates the potential enthalpy of ice from potential temperature of ice (whose reference sea pressure is zero dbar).

Parameters

pt0_icearray-like

Potential temperature of ice (ITS-90), degrees C

Returns

pot_enthalpy_icearray-like, J/kg

potential enthalpy of ice

gsw.ice.pot_enthalpy_from_pt_ice_poly(pt0_ice)

Calculates the potential enthalpy of ice from potential temperature of ice (whose reference sea pressure is zero dbar). This is a compuationally efficient polynomial fit to the potential enthalpy of ice.

Parameters

pt0_icearray-like

Potential temperature of ice (ITS-90), degrees C

Returns

pot_enthalpy_icearray-like, J/kg

potential enthalpy of ice

gsw.ice.pressure_coefficient_ice(t, p)

Calculates pressure coefficient of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

pressure_coefficient_icearray-like, Pa/K

pressure coefficient of ice

gsw.ice.pt0_from_t_ice(t, p)

Calculates potential temperature of ice Ih with a reference pressure of 0 dbar, from in-situ temperature, t.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

pt0_icearray-like, deg C

potential temperature of ice Ih with reference pressure of zero dbar (ITS-90)

gsw.ice.pt_from_pot_enthalpy_ice(pot_enthalpy_ice)

Calculates the potential temperature of ice from the potential enthalpy of ice. The reference sea pressure of both the potential temperature and the potential enthalpy is zero dbar.

Parameters

pot_enthalpy_icearray-like

Potential enthalpy of ice, J/kg

Returns

pt0_icearray-like, deg C

potential temperature of ice (ITS-90)

gsw.ice.pt_from_pot_enthalpy_ice_poly(pot_enthalpy_ice)

Calculates the potential temperature of ice (whose reference sea pressure is zero dbar) from the potential enthalpy of ice. This is a compuationally efficient polynomial fit to the potential enthalpy of ice.

Parameters

pot_enthalpy_icearray-like

Potential enthalpy of ice, J/kg

Returns

pt0_icearray-like, deg C

potential temperature of ice (ITS-90)

gsw.ice.pt_from_t_ice(t, p, p_ref)

Calculates potential temperature of ice Ih with the general reference pressure, p_ref, from in-situ temperature, t.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

p_refarray-like

Reference pressure, dbar

Returns

pt_icearray-like, deg C

potential temperature of ice Ih with reference pressure, p_ref, on the ITS-90 temperature scale

gsw.ice.rho_ice(t, p)

Calculates in-situ density of ice from in-situ temperature and pressure. Note that the output, rho_ice, is density, not density anomaly; that is, 1000 kg/m^3 is not subtracted from it.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

rho_icearray-like, kg/m^3

in-situ density of ice (not density anomaly)

gsw.ice.seaice_fraction_to_freeze_seawater(SA, CT, p, SA_seaice, t_seaice)

Calculates the mass fraction of sea ice (mass of sea ice divided by mass of sea ice plus seawater), which, when melted into seawater having the properties (SA,CT,p) causes the final seawater to be at the freezing temperature. The other outputs are the Absolute Salinity and Conservative Temperature of the final seawater.

Parameters

SAarray-like

Absolute Salinity, g/kg

CTarray-like

Conservative Temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

SA_seaicearray-like

Absolute Salinity of sea ice: the mass fraction of salt in sea ice, expressed in g of salt per kg of sea ice.

t_seaicearray-like

In-situ temperature of the sea ice at pressure p (ITS-90), degrees C

Returns

SA_freezearray-like, g/kg

Absolute Salinity of seawater after the mass fraction of sea ice, w_seaice, at temperature t_seaice has melted into the original seawater, and the final mixture is at the freezing temperature of seawater.

CT_freezearray-like, deg C

Conservative Temperature of seawater after the mass fraction, w_seaice, of sea ice at temperature t_seaice has melted into the original seawater, and the final mixture is at the freezing temperature of seawater.

w_seaicearray-like, unitless

mass fraction of sea ice, at SA_seaice and t_seaice, which, when melted into seawater at (SA,CT,p) leads to the final mixed seawater being at the freezing temperature. This output is between 0 and 1.

gsw.ice.sound_speed_ice(t, p)

Calculates the compression speed of sound in ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

sound_speed_icearray-like, m/s

compression speed of sound in ice

gsw.ice.specvol_ice(t, p)

Calculates the specific volume of ice.

Parameters

tarray-like

In-situ temperature (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

specvol_icearray-like, m^3/kg

specific volume

gsw.ice.t_from_pt0_ice(pt0_ice, p)

Calculates in-situ temperature from the potential temperature of ice Ih with reference pressure, p_ref, of 0 dbar (the surface), and the in-situ pressure.

Parameters

pt0_icearray-like

Potential temperature of ice (ITS-90), degrees C

parray-like

Sea pressure (absolute pressure minus 10.1325 dbar), dbar

Returns

tarray-like, deg C

in-situ temperature (ITS-90)