Update for CF Version:19

The potential enthalpy of a sea water parcel is the specific enthalpy after an adiabatic and isohaline change in pressure from its in situ pressure to the sea pressure p = 0 dbar. "specific" means per unit mass. Reference: www.teos-10.org; McDougall, 2003 doi: 10.1175/1520-0485(2003)033<0945:PEACOV>2.0.CO;2.

"change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. Absolute Salinity, S_A, is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the Intergovernmental Oceanographic Commission (IOC). It is the mass fraction of dissolved material in sea water. Absolute Salinity incorporates the spatial variations in the composition of sea water. This type of Absolute Salinity is also called "Density Salinity". TEOS-10 estimates Absolute Salinity as the salinity variable that, when used with the TEOS-10 expression for density, yields the correct density of a sea water sample even when the sample is not of Reference Composition. In practice, Absolute Salinity is often calculated from Practical Salinity using a spatial lookup table of pre-defined values of the Absolute Salinity Anomaly. It is recommended that the version of (TEOS-10) software and the associated Absolute Salinity Anomaly climatology be specified within metadata by attaching a comment attribute to the data variable. Reference: www.teos-10.org; Millero et al., 2008 doi: 10.1016/j.dsr.2007.10.001. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 onwards), sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

The phrase "change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. Conservative Temperature is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the International Oceanographic Commission (IOC). Conservative Temperature is specific potential enthalpy (which has the standard name sea_water_specific_potential_enthalpy) divided by a fixed value divided by a fixed value of the specific heat capacity of sea water, namely cp_0 = 3991.86795711963 J kg-1 K-1. Conservative Temperature is a more accurate measure of the "heat content" of sea water, by a factor of one hundred, than is potential temperature. Because of this, it can be regarded as being proportional to the heat content of sea water per unit mass. Reference: www.teos-10.org; McDougall, 2003 doi: 10.1175/1520-0485(2003)033<0945:PEACOV>2.0.CO;2.

Preformed Salinity, S*, is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the Intergovernmental Oceanographic Commission (IOC). Preformed Salinity is a salinity variable that is designed to be as conservative as possible, by removing the estimated biogeochemical influences on the sea water composition. Preformed Salinity is Absolute Salinity, S_A (which has the standard name sea_water_absolute_salinity), minus all contributions to sea water composition from biogeochemical processes. Preformed Salinity is the mass fraction of dissolved material in sea water. Reference: www.teos-10.org; Pawlowicz et al., 2011 doi: 10.5194/os-7-363-2011; Wright et al., 2011 doi: 10.5194/os-7-1-2011. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 onwards), and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

Absolute Salinity, S_A, is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the Intergovernmental Oceanographic Commission (IOC). It is the mass fraction of dissolved material in sea water. Absolute Salinity incorporates the spatial variations in the composition of sea water. This type of Absolute Salinity is also called "Density Salinity". TEOS-10 estimates Absolute Salinity as the salinity variable that, when used with the TEOS-10 expression for density, yields the correct density of a sea water sample even when the sample is not of Reference Composition. In practice, Absolute Salinity is often calculated from Practical Salinity using a spatial lookup table of pre-defined values of the Absolute Salinity Anomaly. It is recommended that the version of (TEOS-10) software and the associated Absolute Salinity Anomaly climatology be specified within metadata by attaching a comment attribute to the data variable. Reference: www.teos-10.org; Millero et al., 2008 doi: 10.1016/j.dsr.2007.10.001. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 onwards), sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

"change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. Preformed Salinity, S*, is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the Intergovernmental Oceanographic Commission (IOC). Preformed Salinity is a salinity variable that is designed to be as conservative as possible, by removing the estimated biogeochemical influences on the sea water composition. Preformed Salinity is Absolute Salinity, S_A (which has the standard name sea_water_absolute_salinity), minus all contributions to sea water composition from biogeochemical processes. Preformed Salinity is the mass fraction of dissolved material in sea water. Reference: www.teos-10.org; Pawlowicz et al., 2011 doi: 10.5194/os-7-363-2011; Wright et al., 2011 doi: 10.5194/os-7-1-2011. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 onwards), and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

"change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. The potential enthalpy of a sea water parcel is the specific enthalpy after an adiabatic and isohaline change in pressure from its in situ pressure to the sea pressure p = 0 dbar. "specific" means per unit mass. Reference: www.teos-10.org; McDougall, 2003 doi: 10.1175/1520-0485(2003)033<0945:PEACOV>2.0.CO;2.

Conservative Temperature is defined as part of the Thermodynamic Equation of Seawater 2010 (TEOS-10) which was adopted in 2010 by the International Oceanographic Commission (IOC). Conservative Temperature is specific potential enthalpy (which has the standard name sea_water_specific_potential_enthalpy) divided by a fixed value divided by a fixed value of the specific heat capacity of sea water, namely cp_0 = 3991.86795711963 J kg-1 K-1. Conservative Temperature is a more accurate measure of the "heat content" of sea water, by a factor of one hundred, than is potential temperature. Because of this, it can be regarded as being proportional to the heat content of sea water per unit mass. Reference: www.teos-10.org; McDougall, 2003 doi: 10.1175/1520-0485(2003)033<0945:PEACOV>2.0.CO;2.

Practical Salinity, S_P, is defined on the Practical Salinity Scale of 1978 (PSS-78) and is calculated from the electrical conductivity of sea water (as well as temperature and pressure). Officially S_P is dimensionless so that, while convenient, and while it is common practice, it is not officially sanctioned to say S_P = 35 psu. Often authors use PSS-78, as in S_P = 35 PSS-78. If salinity was measured using remote sensing techniques and not conductivity, then it is recommended that additional metadata (calibration/validation information) be described in the variable comment attribute. This name should be used to describe salinity observations made from 1978 onwards (Practical Salinity is the salinity quantity stored by national data centres for post-1978 observations). The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity. Reference: www.teos-10.org; Lewis, 1980 doi:10.1109/JOE.1980.1145448

"X_area" means the horizontal area occupied by X within the grid cell. "Burned area" means the area of burned vegetation.

Knudsen Salinity, S_K, is defined unitless as a mass fraction per mil (0/00) or "parts per thousand", and was calculated from the titration of inorganic salts from a sample of sea water after a commission to study the problem of determining salinity and density was initiated by the International Council for the Exploration of the Sea (ICES) in 1899. S_K was the standard salinity measure until S_C (Cox Salinity) was established in 1967. Since the work of Knudsen (1901), chlorinity is converted into Knudsen Salinity using S_K = 0.030 + 1.805 Cl. This type of salinity was called simply "salinity" from 1901 to 1966. From the 1960s on, electrical conductivity began to be used to estimate the Knudsen Salinity, rather than chemical titration. Knudsen Salinity was replaced by Cox Salinity in 1967 which was in turn replaced by Practical Salinity, S_P, in 1978. Conversion of Knudsen Salinity to Practical Salinity follows S_P = (S_K - 0.03) * (1.80655 / 1.805). Reference: Knudsen, 1901; Thomas et al., 1934 doi: 10.1093/icesjms/9.1.28; Lyman, 1969 doi: 10.4319/lo.1969.14.6.0928; Wooster et al., 1969 doi: 10.4319/lo.1969.14.3.0437; Lewis, 1980 doi: 10.1109/JOE.1980.1145448; Millero et al., 2008 doi: 10.1016/j.dsr.2007.10.001. There are standard names for the precisely defined salinity quantities sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P, sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_* and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

Cox Salinity, S_C, is defined unitless as a mass fraction per mil (0/00) or "parts per thousand". S_C was the standard salinity measure from 1967 until Practical Salinity, S_P, was established with PSS-78 (1978). Chlorinity, Cl, is calculated from the conductivity of a sea water sample and since the work of the Joint Panel for Oceanographic Tables and Standards (JPOTS; 1966) is converted into Cox Salinity using S_C = 1.80655Cl. This type of salinity was called simply "salinity" from 1967 to 1978. Cox Salinity was replaced by Practical Salinity in 1978. Cox Salinity is converted to Practical Salinity following S_P = S_C, however the accuracy of this is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of the Practical Salinity Scale 1978 (PSS-78). Reference: Cox et al., 1967 doi: 10.1016/0011-7471(67)90006-X; Lyman, 1969 doi: 10.4319/lo.1969.14.6.0928; Wooster et al., 1969 doi: 10.4319/lo.1969.14.3.0437. There are standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_practical_salinity, S_P, sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_* and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

The brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area. "anomaly" means difference from climatology.

"change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. Practical Salinity, S_P, is defined on the Practical Salinity Scale of 1978 (PSS-78) and is calculated from the electrical conductivity of sea water (as well as temperature and pressure). Officially S_P is dimensionless so that, while convenient, and while it is common practice, it is not officially sanctioned to say S_P = 35 psu. Often authors use PSS-78, as in S_P = 35 PSS-78. If salinity was measured using remote sensing techniques and not conductivity, then it is recommended that additional metadata (calibration/validation information) be described in the variable comment attribute. This name should be used to describe salinity observations made from 1978 onwards (Practical Salinity is the salinity quantity stored by national data centres for post-1978 observations). The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity. Reference: www.teos-10.org; Lewis, 1980 doi: 10.1109/JOE.1980.1145448

"change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and the units attribute should normally be given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

If a sea water sample has the Reference Composition (defined in Millero et al., 2008), then its Reference Salinity is the best available estimate of its Absolute Salinity. For general purposes, Reference Salinity is (35.16504 g kg-1)/35 times Practical Salinity. Reference: www.teos-10.org; Millero et al., 2008 doi: 10.1016/j.dsr.2007.10.001. There are also standard names for the precisely defined salinity quantities sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity (used for salinity observations from 1978 onwards), sea_water_absolute_salinity, S_A, and sea_water_preformed_salinity, S_*. Salinity quantities that do not match any of the precise definitions should be given the more general standard name of sea_water_salinity.

"integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Depth is the vertical distance below the surface. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

"integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Depth is the vertical distance below the surface. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

The phrase "tendency_of_X" means derivative of X with respect to time. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

"tendency_of_X" means derivative of X with respect to time. Bolus advection in an ocean model means the part due to a scheme representing eddy-induced effects not included in the velocity field. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

"product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

"product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

The phrase "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

Mole fraction is used in the construction mole_fraction_of_X_in_Y, whereX is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Methylglyoxal is an organic molecule with the chemical formula CH3COCHO. It is also called pyruvaldehyde or 2-oxopropanal.

The phrase "tendency_of_X" means derivative of X with respect to time. "Vertical mixing" means any vertical transport other than by advection and bolus advection, represented by a combination of vertical diffusion, turbulent mixing and convection in ocean models. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

"tendency_of_X" means derivative of X with respect to time. "Vertical mixing" means any vertical transport other than by advection and bolus advection, represented by a combination of vertical diffusion, turbulent mixing and convection in ocean models. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

The phrase "tendency_of_X" means derivative of X with respect to time. "Horizontal mixing" means any horizontal transport other than by advection and bolus advection, usually represented as horizontal diffusion in ocean models. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water temperature is the in situ temperature of the sea water. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient aerosol" is aerosol that has taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the aerosol. "Pm10 aerosol" is an air pollutant with an aerodynamic diameter of less than or equal to 10 micrometers. To specify the relative humidity and temperature at which the particle size applies, provide scalar coordinate variables with the standard names of, respectively, "relative_humidity" and "air_temperature."

Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient aerosol" is aerosol that has taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the aerosol. "Pm1 aerosol" is an air pollutant with an aerodynamic diameter of less than or equal to 1 micrometer. To specify the relative humidity and temperature at which the particle size applies, provide scalar coordinate variables with the standard names of, respectively, "relative_humidity" and "air_temperature".

Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient aerosol" is aerosol that has taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the aerosol. "Pm2p5 aerosol" is an air pollutant with an aerodynamic diameter of less than or equal to 2.5 micrometers. To specify the relative humidity and temperature at which the particle size applies, provide scalar coordinate variables with the standard names of, respectively, "relative_humidity" and "air_temperature."

The phrase "change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate.Sea water temperature is the in situ temperature of the sea water. To specify the depth at which the temperature applies use a vertical coordinate variable or scalar coordinate variable. There are standard names for sea_surface_temperature, sea_surface_skin_temperature, sea_surface_subskin_temperature and sea_surface_foundation_temperature which can be used to describe data located at the specified surfaces. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and the units attribute should normally be given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

Mole fraction is used in the construction mole_fraction_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Alkanes are saturated hydrocarbons, i.e. they do not contain any chemical double bonds. Alkanes contain only hydrogen and carbon combined in the general proportions C(n)H(2n+2); "alkanes" is the term used in standard names to describe the group of chemical species having this common structure that are represented within a given model. The list of individual species that are included in a quantity having a group chemical standard name can vary between models. Where possible, the data variable should be accompanied by a complete description of the species represented, for example, by using a comment attribute. Standard names exist for some individual alkane species, e.g., methane and ethane.

"X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. "Burned area" means the area of burned vegetation.

Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient aerosol" is aerosol that has taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the aerosol. Coarse mode aerosol is aerosol having a diameter of more than 1 micrometer.

"tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

Sea surface salinity is the salt content of sea water close to the sea surface, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and the units attribute should normally be given as 1e-3 or 0.001 i.e. parts per thousand. Sea surface salinity is often abbreviated as "SSS". For the salinity of sea water at a particular depth or layer, a data variable of "sea_water_salinity" or one of the more precisely defined salinities should be used with a vertical coordinate axis. There are standard names for the precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

"tendency_of_X" means derivative of X with respect to time. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

"tendency_of_X" means derivative of X with respect to time. "Horizontal mixing" means any horizontal transport other than by advection and bolus advection, usually represented as horizontal diffusion in ocean models. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

Mole fraction is used in the construction mole_fraction_of_X_in_Y, whereX is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Dichlorine is the molecular form of elemental chlorine with the chemical formula Cl2.

Mole fraction is used in the construction mole_fraction_of_X_in_Y, whereX is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Aldehydes are organic compounds with a CHO group; "aldehydes" is the term used in standard names to describe the group of chemical species having this common structure that are represented within a given model. The list of individual species that are included in a quantity having a group chemical standard name can vary between models. Where possible, the data variable should be accompanied by a complete description of the species represented, for example, by using a comment attribute. Standard names exist for formaldehyde as the simplest member of the aldehydes group.

"tendency_of_X" means derivative of X with respect to time. "Sea ice thermodynamics" refers to the addition or subtraction of sea ice mass due to surface and basal fluxes. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.

Sea water temperature is the in situ temperature of the sea water. To specify the depth at which the temperature applies use a vertical coordinate variable or scalar coordinate variable. There are standard names for sea_surface_temperature, sea_surface_skin_temperature, sea_surface_subskin_temperature and sea_surface_foundation_temperature which can be used to describe data located at the specified surfaces. For observed data, depending on the period during which the observation was made, the measured in situ temperature was recorded against standard "scales". These historical scales include the International Practical Temperature Scale of 1948 (IPTS-48; 1948-1967), the International Practical Temperature Scale of 1968 (IPTS-68, Barber, 1969; 1968-1989) and the International Temperature Scale of 1990 (ITS-90, Saunders 1990; 1990 onwards). Conversion of data between these scales follows t68 = t48 - (4.4 x 10e-6) * t48(100 - t - 48); t90 = 0.99976 * t68. Observations made prior to 1948 (IPTS-48) have not been documented and therefore a conversion cannot be certain. Differences between t90 and t68 can be up to 0.01 at temperatures of 40 C and above; differences of 0.002-0.007 occur across the standard range of ocean temperatures (-10 - 30 C). The International Equation of State of Seawater 1980 (EOS-80, UNESCO, 1981) and the Practical Salinity Scale (PSS-78) were both based on IPTS-68, while the Thermodynamic Equation of Seawater 2010 (TEOS-10) is based on ITS-90. References: Barber, 1969, doi: 10.1088/0026-1394/5/2/001; UNESCO, 1981; Saunders, 1990, WOCE Newsletter, 10, September 1990.

Mole fraction is used in the construction mole_fraction_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. The chemical formula of hydrogen sulfide is H2S.

Sea ice salinity is the salt content of sea ice, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s.

"tendency_of_X" means derivative of X with respect to time. Bolus advection in an ocean model means the part due to a scheme representing eddy-induced effects not included in the velocity field. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Sea water salinity is the salt content of sea water, often on the Practical Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and does not necessarily imply any particular method of calculation. The units of salinity are dimensionless and normally given as 1e-3 or 0.001 i.e. parts per thousand. There are standard names for the more precisely defined salinity quantities: sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 1967 and 1977), sea_water_practical_salinity, S_P (used for salinity observations from 1978 to the present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, S_*, and sea_water_reference_salinity. Practical Salinity is reported on the Practical Salinity Scale of 1978 (PSS-78), and is usually based on the electrical conductivity of sea water in observations since the 1960s. Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * (1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is dependent on whether chlorinity or conductivity was used to determine the S_C value, with this inconsistency driving the development of PSS-78. The more precise standard names should be used where appropriate for both modelled and observed salinities. In particular, the use of sea_water_salinity to describe salinity observations made from 1978 onwards is now deprecated in favor of the term sea_water_practical_salinity which is the salinity quantity stored by national data centers for post-1978 observations. The only exception to this is where the observed salinities are definitely known not to be recorded on the Practical Salinity Scale. The unit "parts per thousand" was used for sea_water_knudsen_salinity and sea_water_cox_salinity.