4.2.6.  DATA_VARIABLES


The global attribute DATA_VARIABLES lists all data variables reported in the current data file. The list is a succession of fields in the DATA_VARIABLES entry; in other words, the entry consists of one field per variable. Generally, a field consists of the variable name, the variable modeand the variable descriptor, separated by underscores. 


Type: STRING

Entry: Arbitrary number of semicolon-separated fields (each field constructed according to the format below)

Format: Variable name[_Variable mode][_Variable descriptor]

Example 1: DATA_VARIABLES = DATETIME; LATITUDE; LONGITUDE; ALTITUDE.GPH;  O3.PARTIAL.PRESSURE_INSITU; PRESSURE_INSITU; TEMPERATURE_INSITU;HUMIDITY.RELATIVE_INSITU; INTERNAL.BOX.TEMPERATURE_INSITU

Example 2: DATA_VARIABLES = DATETIME;LATITUDE.INSTRUMENT;  LONGITUDE.INSTRUMENT; ALTITUDE.INSTRUMENT; ALTITUDE; H2O.COLUMN_ABSORPTION.SOLAR where ALTITUDEis an independent parameter and H2O.COLUMN_ABSORPTION.SOLAR is dependent on DATETIME and ALTITUDE.

The variables DATETIME, ALTITUDE (.INSTRUMENT) or any other vertical coordinate, LATITUDE (.INSTRUMENT) and LONGITUDE(.INSTRUMENT) variables are always mode-lessand descriptor-less. All other variables can have an optional modeand an optional descriptoras appropriate.

With some exceptions (cf. Section 4.2.6.4) variable names first refer to a geophysical entity followed by a physical property.

 

4.2.6.1.  Variable name

The variable nameis a basic identification of the data parameter described in the dataset, e.g., the geophysical entity that is reported. The name includes the chemical or physical identification of the reported entity. A typical example of a variable name is the column amount of ozone: O3.COLUMN


Name Comment
ABSORPTION.COEFFICIENT -
AEROSOL.ABSORPTION.OPTICAL.DEPTH -
AEROSOL.ABSORPTION.OPTICAL.DEPTH.LEVEL OVP
AEROSOL.ASYMMETRY.FACTOR -
AEROSOL.BACKSCATTER.RATIO -
AEROSOL.COLUMN -
AEROSOL.DEPOLARIZATION.RATIO -
AEROSOL.EXTINCTION.COEFFICIENT -
AEROSOL.INDEX -
AEROSOL.LAYER.HEIGHT -
AEROSOL.OPTICAL.DEPTH -
AEROSOL.OPTICAL.DEPTH.LEVEL OVP
AEROSOL.OPTICAL.DEPTH.STRATOSPHERIC -
AEROSOL.OPTICAL.DEPTH.TROPOSPHERIC -
AEROSOL.SINGLE.SCATTERING.ALBEDO -
AEROSOL.SINGLE.SCATTERING.ALBEDO.LEVEL OVP
AEROSOL.TYPE -
AIR.MASS NDACC FTIR
ALBEDO.SURFACE -
ALTITUDE -
ALTITUDE.BOUNDARIES Upper and lower boundaries of a partial column altitude grid.
ALTITUDE.GPH.BOUNDARIES -
ALTITUDE.GPH Geopotential Height
ALTITUDE.INSTRUMENT -
ANEMOMETER.HEIGHT -
ANGLE EVDC
ANGLE.LUNAR -
ANGLE.SOLAR Solar angle
ANGLE.VIEW Viewing angle
ATMOSPHERIC.TRANSMISSION EVDC
AUXILIARY.PARAMETERS used for SONDE
BACKSCATTERING.COEFFICIENT -
BAROMETRIC.PRESSURE EVDC
BPA Bleached Particle Absorption
BrO.COLUMN -
BrO.COLUMN.PARTIAL -
BrO.COLUMN.SLANT -
BrO.COLUMN.SLANT.DIFFERENTIAL -
BrO.COLUMN.SLANT.TROPOSPHERIC -
BrO.COLUMN.STRATOSPHERIC -
BrO.COLUMN.TROPOSPHERIC -
BrO.MIXING.RATIO -
C2H2.COLUMN -
C2H2.COLUMN.PARTIAL -
C2H2.MIXING.RATIO -
C2H6.COLUMN -
C2H6.COLUMN.PARTIAL -
C2H6.MIXING.RATIO PPV
CCl2F2.COLUMN -
CCl2F2.COLUMN.PARTIAL -
CCl2F2.MIXING.RATIO -
CCl3F.COLUMN -
CCl3F.COLUMN.PARTIAL -
CCl3F.MIXING.RATIO -
CFC11.MIXING.RATIO -
CFC12.MIXING.RATIO -
CH4.COLUMN -
CH4.COLUMN EVDC
CH4.COLUMN.PARTIAL -
CH4.MIXING.RATIO -
CH4.NUMBER.DENSITY -
CHF2Cl.COLUMN -
CHF2Cl.COLUMN.PARTIAL -
CHF2Cl.MIXING.RATIO -
CHL.1.CONCENTRATION -
CHL.1.INDEX -
CHL.2.INDEX -
CHL.2.INDEX -
CHL.2.INDEX -
CHL.A.CONCENTRATION -
CHOCHO.COLUMN -
CHOCHO.COLUMN.PARTIAL -
CHOCHO.COLUMN.TROPOSPHERIC -
CHOCHO.MIXING.RATIO -
ClO.MIXING.RATIO Volumetric mixing ratio (ppv)
ClONO2.COLUMN -
ClONO2.COLUMN.PARTIAL -
ClONO2.MIXING.RATIO Volumetric mixing ratio (ppv)
CLOUD.BOTTOM.HEIGHT -
CLOUD.FRACTION OVP
CLOUD.LAYER.THICKNESS EVDC
CLOUD.TOP.HEIGHT -
CLOUD.TOP.PRESSURE -
CO2.COLUMN -
CO2.COLUMN.PARTIAL -
CO2.MIXING.RATIO Volumetric mixing ratio (ppv)
CO2.NUMBER.DENSITY -
CO.COLUMN -
CO.COLUMN.PARTIAL -
CO.MIXING.RATIO Volumetric mixing ratio (ppv)
CO.NUMBER.DENSITY -
COF2.COLUMN -
COF2.COLUMN.PARTIAL -
COF2.MIXING.RATIO -
COLOUR.INDEX Wavelength ratio derived from UVVIS.SAOZ instruments
DATETIME -
DATETIME.START -
DATETIME.STOP -
DAY.OF.YEAR EVDC
DENSITY.DRY -
DENSITY NDACC LIDAR T
DEPTH -
DEPTH.KD For MERIS validation
DEPTH.SEA.FLOOR -
DEPTH.SECCHI Depth using Secchi disk
DEW.POINT.TEMPERATURE -
DISCOLOUR.CODE For MERIS validation
DISTANCE.SHORE -
F12.COLUMN -
F22.COLUMN -
FLAG.ALGORITHM -
FLAG.ALGORITHM.LEVEL OVP
FLAG.MEASUREMENT.QUALITY OVP
FLAG.PROCESSING.QUALITY OVP
FLAG.TARGET -
FREQUENCY.BIN GECA
FREQUENCY.SIGNAL Radio Occultation
H2CO.COLUMN -
H2CO.COLUMN.PARTIAL -
H2CO.COLUMN.TROPOSPHERIC -
H2CO.MIXING.RATIO -
H2.MIXING.RATIO -
H2O.COLUMN -
H2O.COLUMN.PARTIAL -
H2O.COLUMN.STRATOSPHERIC -
H2O.COLUMN.TROPOSPHERIC -
H2O.LIQUID.COLUMN -
H2O.MIXING.RATIO -
H2O.NUMBER.DENSITY -
HCFC22.COLUMN -
HCFC22.COLUMN.PARTIAL -
HCFC22.MIXING.RATIO PPV
HCl.COLUMN -
HCl.COLUMN.PARTIAL -
HCl.MIXING.RATIO -
HCl.NUMBER.DENSITY -
HCN.COLUMN -
HCN.COLUMN.PARTIAL -
HCN.MIXING.RATIO Volumetric mixing ratio (ppv)
HCOOH.COLUMN -
HCOOH.COLUMN.PARTIAL -
HCOOH.MIXING.RATIO -
HEIGHT.TERRAIN -
HF.COLUMN -
HF.COLUMN.PARTIAL -
HF.MIXING.RATIO Volumetric mixing ratio (ppv)
HNO3.COLUMN -
HNO3.COLUMN.PARTIAL -
HNO3.MIXING.RATIO Volumetric mixing ratio (ppv)
HNO3.NUMBER.DENSITY -
HONO.COLUMN -
HONO.COLUMN.PARTIAL -
HONO.COLUMN.TROPOSPHERIC -
HONO.MIXING.RATIO -
HUMIDITY.RELATIVE Relative humidity (%)
HUMIDITY.SPECIFIC -
INTEGRATION.TIME -
INTERNAL.BOX.TEMPERATURE -
INTERNAL.INSTRUMENT.TEMPERATURE -
IO.COLUMN -
IO.COLUMN.PARTIAL -
IO.COLUMN.STRATOSPHERIC -
IO.COLUMN.TROPOSPHERIC -
IO.MIXING.RATIO -
IRRADIANCE.DOWNWELLED -
IRRADIANCE.UPWELLED -
LAND.SURFACE.TEMPERATURE -
LATITUDE -
LATITUDE.INSTRUMENT -
LEAF.AREA.INDEX -
LEVEL EVDC
LONGITUDE -
LONGITUDE.INSTRUMENT -
N2.COLUMN -
N2O.COLUMN -
N2O.COLUMN.PARTIAL -
N2O.MIXING.RATIO -
N2O.NUMBER.DENSITY -
NH3.COLUMN -
NO2.COLUMN -
NO2.COLUMN.PARTIAL -
NO2.COLUMN.SLANT -
NO2.COLUMN.SLANT.DIFFERENTIAL -
NO2.COLUMN.STRATOSPHERIC -
NO2.COLUMN.TROPOSPHERIC -
NO2.MIXING.RATIO Volumetric mixing ratio (ppv)
NO2.NUMBER.DENSITY -
NO3.MIXING.RATIO -
NO3.NUMBER.DENSITY -
NO.COLUMN -
NO.COLUMN.PARTIAL -
NO.MIXING.RATIO -
NO.NUMBER.DENSITY -
NOY.MIXING.RATIO -
NUMBER.DENSITY -
O3.COLUMN -
O3.COLUMN.PARTIAL -
O3.COLUMN.SLANT -
O3.COLUMN.SLANT.DIFFERENTIAL -
O3.COLUMN.STRATOSPHERIC -
O3.COLUMN.TROPOSPHERIC -
O3.MIXING.RATIO Volumetric mixing ratio (ppv)
O3.NUMBER.DENSITY -
O3.PARTIAL.PRESSURE -
O4.COLUMN -
OClO.COLUMN -
OClO.COLUMN.PARTIAL -
OClO.COLUMN.SLANT -
OClO.COLUMN.SLANT.DIFFERENTIAL -
OClO.COLUMN.STRATOSPHERIC -
OClO.MIXING.RATIO -
OClO.NUMBER.DENSITY -
OCS.COLUMN -
OCS.COLUMN.PARTIAL -
OCS.MIXING.RATIO -
OH.COLUMN -
OPACITY.ATMOSPHERIC -
OPACITY.ATMOSPHERIC.VERTICAL -
ORBIT.NUMBER -
PATH.DIFFERENCE -
PIXEL.DISTANCE -
PIXEL.NUMBER -
POTENTIAL.VORTICITY EVDC
PRESSURE -
PRESSURE.BOUNDARIES -
PRESSURE.DRY -
PRESSURE.LEVEL.INDEX -
PUMP.CORRECTION sonde
RADIANCE.DOWNWELLED.SKY EVDC
RADIANCE.DOWNWELLING -
RADIANCE.UPWELLED -
RADIANCE.UPWELLING -
RANGE -
REFLECTANCE -
REFLECTANCE.RHOW Water-leaving reflectance
REFLECTIVITY -
REFRACTIVITY Radio Occultation
SALINITY -
SEA.STATE -
SEA.SURFACE.HEIGHT -
SEA.SURFACE.PRESSURE -
SEA.SURFACE.TEMPERATURE -
SEA.SURFACE.TEMPERATURE.SKIN -
SEA.SURFACE.TEMPERATURE.SUBSKIN GECA
SEA.SURFACE.WAVE.HEIGHT.SIGNIFICANT GECA
SEA.SURFACE.WAVE.HEIGHT.SWELL GECA
SEA.SURFACE.WAVE.SPECTRAL.DENSITY.VARIANCE GECA
SF6.COLUMN -
SF6.COLUMN.PARTIAL -
SF6.MIXING.RATIO -
SITE.CROP -
SITE.FIELD -
SITE.POINT -
SKY.CODE -
SKY.CONDITION -
SO2.COLUMN -
SO2.COLUMN.PARTIAL -
SO2.COLUMN.STRATOSPHERIC -
SO2.COLUMN.TROPOSPHERIC -
SO2.MIXING.RATIO -
SOURCE.PRODUCT -
SPEED -
SURFACE.CODE -
SURFACE.PRESSURE Pressure at surface (NDACC FTIR)
SURFACE.TEMPERATURE Temperature at surface (NDACC FTIR)
TEMPERATURE -
TEMPERATURE.BRIGHTNESS -
TEMPERATURE.DRY -
TEMPERATURE.RADIOMETRIC -
THETA -
TROPOSPHERIC.DELAY GPS measurement delay
TSM.CONCENTRATION -
UV.INDEX EVDC
VISIBILITY -
WAVE.DIRECTION -
WAVELENGTH -
WAVELENGTH.CENTRAL -
WAVELENGTH.FWHM -
WAVENUMBER EVDC
WAVE.TYPE -
WIND.DIRECTION -
WIND.SPEED -
YSBPA Yellow Substance + Bleached Particle Absorption
YS Yellow Substance
AVERAGE.WAVE.PERIOD -
DOMINANT.WAVE.DIRECTION -
DOMINANT.WAVE.PERIOD -
O2.DISSOLVED.MIXING.RATIO -
O2.DISSOLVED.NUMBER.DENSITY -
PROFILE.DATA.MODE -
PROFILE.DIRECTION -
SEA.DEPTH -
SIGNIFICANT.WAVE.HEIGHT -
SONDE.BATTERY.VOLTAGE -
SONDE.PUMP.CURRENT -
SONDE.RAW.CURRENT -
WATER.PRESSURE -
WATER.TEMPERATURE -
WAVE.DIRECTIONAL.SPECTRUM -
WAVE.FREQUENCY.SPECTRUM -
WIND.SPEED.GUST -
ICE.TEMPERATURE -
POTENTIAL.TEMPERATURE -


4.2.6.2.  Variable mode

The variable mode provides the information on the measurement/calculation method that can lead to differences when comparing to results obtained with other methods to observe/calculate the same quantity. It is optionalin the construction of every field in the DATA_VARIABLES entry. 

Examples related to ozone observations compliant with Table 7.2 are:

O3.COLUMN.SLANT_ABSORPTION.SOLAR

O3.COLUMN_ABSORPTION.SOLAR


Mode Comment
A442 EVDC
ABSORPTION.DIFFERENTIAL for DIAL
ABSORPTION.DIFFERENTIAL.STD -
ABSORPTION EVDC
ABSORPTION.LUNAR -
ABSORPTION.SOLAR -
APRIORI EVDC
AZIMUTH -
B442 EVDC
BACKSCATTER -
BACKSCATTER.RAMAN -
BACKSCATTER.SOLAR -
BACKSCATTER.STD -
DIFF.SAT.BUOY EVDC
DIFFSLANT EVDC
DIFFSLANT.ZENITH EVDC
DIRECTIONAL GECA
DRYW EVDC
EASTWARD GECA
ELEVATION EVDC
EMISSION -
FOV EVDC
HPLC EVDC
INDEPENDENT Generic Term
INSITU -
INTERFEROGRAMME EVDC
LIMB EVDC
NADIR EVDC
NORTHWARD GECA
OCCULTATION.SOLAR With reference to the solar occultation
PARALLEL EVDC
PERPENDICULAR EVDC
REFRACTION -
SAMPLE -
SCATTER.SOLAR -
SCATTER.SOLAR.OFFAXIS -
SCATTER.SOLAR.ZENITH -
SKY EVDC
SPECTRAL GECA
SP EVDC
TRANSECT EVDC
U EVDC
V EVDC
W EVDC
ZENITH -
ZENITH.ASTRONOMICAL -
CENTRAL.FREQUENCY -
FREQUENCY.RANGE -
GPS -
SPECTRAL.DENSITY -
R1 BUOY
R2 BUOY
ALPHA1 BUOY
ALPHA2 BUOY
DERIVED -


4.2.6.3.  Variable descriptor

The variable descriptoris added only to construct variables that provide additional information about a primary variable or that describe some particular property of that variable. For instance for the ozone examples above, we may add additional variables as follow:

O3.COLUMN.SLANT_ABSORPTION.SOLAR_UNCERTAINTY.STDEV

O3.COLUMN_ABSORPTION.SOLAR_UNCERTAINTY.STDEV

The descriptor is not intended to distinguish subsets of a dataset. Such dataset distinctions should be made by

providing additional dependent or independent parameters, as outlined in the following examples:

Example 1:

The ozone columns obtained by SAOZ measurements are traditionally distinguished in two

subsets: measurements at dawn and measurements at dusk. The solar azimuth angle is the

relevant parameter distinguishing these measurements and should be provided together with

every measurement of the ozone column. 

Example 2:

Irradiance/radiance measurements are often performed at specific wavelengths. Wavelength

should therefore be an independent parameter if values at more than one wavelength are

reported.

Example 3:

For an instrument capable of measuring in alternating modes, for example zenith sky  vs.direct

sun, the data taken in these modes should be reported as distinct variables constructed with

different variable modes.

O3.COLUMN.SLANT_ZENITH

O3.COLUMN.SLANT_ABSORPTION.SOLAR

Descriptor Comment
AMF Air Mass Factor
APPARENT EVDC
APRIORI -
APRIORI.CONTRIBUTION -
ASTRONOMICAL EVDC
AVK Averaging Kernel
CONTRIBUTION EVDC
FINAL -
FLAG EVDC
INITIALIZATION NDACC LIDAR T
MEAN -
MEASUREMENT.SPACING EVDC
MEDIAN -
NORMALIZATION NDACC LIDAR T
RESOLUTION.ALTITUDE -
RESOLUTION.ALTITUDE.DFCUTOFF NDACC LIDAR
RESOLUTION.ALTITUDE.STD NDSC LIDAR WG standard altitude resolution
RESOLUTION EVDC
UNCERTAINTY.RANDOM -
UNCERTAINTY.RELATIVE -
UNCERTAINTY.RMS -
UNCERTAINTY.STDEV -
UNCERTAINTY.SYSTEMATIC -
UNCERTAINTY.TOTAL -
AVW Averaging weights
CALIBRATION.FACTOR -
CALIBRATION.SOURCE -
CALIBRATION.UNCERTAINTY -
RESOLUTION.ALTITUDE.ORIGINATOR -
TRANSFER.FUNCTION -
UNCERTAINTY -
UNCERTAINTY.CORRELATED -
UNCERTAINTY.ORIGINATOR -
UNCERTAINTY.UNCORRELATED -


4.2.6.4.  Special variables

PRESSURE, TEMPERATURE, SURFACE.TEMPERATURE, DENSITY, and HUMIDITY:

Special rules apply for variable names referring to air. The variable name to be used does not explicitly carry the AIR keyword, but implicitly refers to air, e.g. TEMPERATUREinstead of AIR.TEMPERATURE. Note, SURFACE.TEMPERATURErefers the the air temperature above the surface. In case another medium than  AIRis measured, the medium or identifier will be on the first position, e.g. INTERNAL.BOX.TEMPERATURE, ICE.TEMPERATURE, or LAND.SURFACE.TEMPERATURE. 

The same approach is valid for gases mixed in air, e.g. CH4.MIXING.RATIO. The only variable still carrying the AIRkeyword is AIR.MASS. DATETIME, LATITUDE, LONGITUDE, ALTITUDE[.GPH], PRESSURE, DEPTH: 

These variable names refer to effective geolocation (mid-time/point) of a reported parameter.

 

4.2.6.5.  Geolocation

Every data file mustcontain a specification of geolocation in three or four dimensions(cf. Section 2.3), specifying when and where the reported data is sampled. In other words, the  DATETIME variable, as well as latitude and longitude are mandatorywith a vertical geolocation variable only mandatory if the measurement has been taken in the corresponding dimension.The vertical geolocation should be expressed as ALTITUDE or DEPTH. If ALTITUDE is not available, acceptable substitutes are PRESSUREand ALTITUDE.GPH 

(geopotential height), etc. If no altitude parameter is measured, the altitude of the instrument position should be given, if it makes sense for the observation, e.g. ALTITUDE.INSTRUMENT.

 

The geolocation variables must comply with stringent naming criteria. Acceptable combinations of geolocation

variables are:

 

• DATETIME;LATITUDE;LONGITUDE;[ALTITUDE|ALTITUDE.GPH|PRESSURE]

• DATETIME;LATITUDE;LONGITUDE;DEPTH

• DATETIME;LATITUDE.INSTRUMENT;LONGITUDE.INSTRUMENT;

ALTITUDE.INSTRUMENT;[LATITUDE;LONGITUDE;

[ALTITUDE|ALTITUDE.GPH|PRESSURE]]