Embedded Files
Provider Defined Variables
Provider Defined Variables
All variables defined by the provider have the following attributes.
type
Definition: data type of variable
Example: int32, float32, byte
dimension
Definition: Dimensions of variable. Time is always the first followed by altitude or range when dealing with profiles. Additional dimensions are added at the end.
Example: time
time, index
time, index_range, index_angle
units
Definition: Units of a variable’s content.
Example: m s-1
standard_name
Definition: A standard name that references a description of a variable’s content in the standard name table.
Example: air_temperature. If no standard name exists then the attribute is not saved
long_name
Definition: Long descriptive name which is often used for labelling plots
Example: Temperature
_FillValue
Definition: This value is considered to be a special value that indicates undefined or missing data, and is returned when reading values that were not written
Example: -1e+20
valid_min
Definition: Smallest valid value of a variable.
Example: -19
valid_max
Definition: Largest valid value of a variable.
Example: 19
cell_methods
Definition: Records the method used to derive data that represents cell values.
Example: time: mean
coordinates
Definition: Identifies auxiliary coordinate variables, label variables, and alternate coordinate variables.
Example: latitude longitude
In some cases additional information is required: for example gas phase chemical species. In these cases two additional variable attributes are used
practical_units
Definition: The common community nomenclature for the canonical unit.
Example: ppb
chemical_species
Definition: The common community nomenclature for the canonical unit.
Example: CH4
Example: A profile of wind direction
wind_from_direction
type: float32
dimension: time, index
units: degree
standard_name: wind_from_direction
long_name: Wind Direction
_FillValue: -1.00E+20
valid_min: 88.4
valid_max: 275.6
cell_methods: time: mean
coordinates: latitude longitude
Example: An Ozone Measurement
mole_fraction_of_ozone_in_air
type: float32
dimension: time
units: 1e-9
proctical_units: ppb
standard_name: mole_fraction_of_ozone_in_air
long_name: Mole Fraction of Ozone in air
_FillValue: -1.00E+20
valid_min: 0.6
valid_max: 27
cell_methods: time: mean
coordinates: latitude longitude
chemical_species: O3
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