Update for CF Version:81

sea_water_electrical_conductivity_at_reference_temperature

Unit: S m-1
Unit ref: UECA
The electrical conductivity of sea water in a sample measured at a defined reference temperature. The reference temperature should be recorded in a scalar coordinate variable, or a coordinate variable with a single dimension of size one, and the standard name of temperature_of_analysis_of_sea_water. This quantity is sometimes called 'specific conductivity' when the reference temperature 25 degrees Celsius.

number_size_distribution_of_aerosol_particles_in_air

Unit: m-3
Unit ref: PCUM
The aerosol particle number size distribution is the number concentration of aerosol particles as a function of particle diameter. A coordinate variable with the standard name of electrical_mobility_particle_diameter, aerodynamic_particle_diameter, or optical_particle_diameter should be specified to indicate that the property applies at specific particle sizes selected by the indicated method. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection.

number_size_distribution_of_cloud_condensation_nuclei_in_air

Unit: m-3
Unit ref: PCUM
The cloud condensation nuclei number size distribution is the number concentration of aerosol particles as a function of particle diameter, where the particle acts as condensation nucleus for liquid-phase clouds. A coordinate variable with the standard name of relative_humidity should be specified to indicate that the property refers to a specific supersaturation with respect to liquid water. A coordinate variable with the standard name of electrical_mobility_particle_diameter should be specified to indicate that the property applies at specific mobility particle sizes. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. The ability of a particle to act as a condensation nucleus is determined by its size, chemical composition, and morphology.

log10_size_interval_based_number_size_distribution_of_aerosol_particles_at_stp_in_air

Unit: m-3
Unit ref: PCUM
The aerosol particle number size distribution is the number concentration of aerosol particles, normalised to the decadal logarithmic size interval the concentration applies to, as a function of particle diameter. A coordinate variable with the standard name of electrical_mobility_particle_diameter, aerodynamic_particle_diameter, or optical_particle_diameter should be specified to indicate that the property applies at specific particle sizes selected by the indicated method. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. "log10_X" means common logarithm (i.e. base 10) of X. "stp" means standard temperature (0 degC) and pressure (101325 Pa).

number_size_distribution_of_aerosol_particles_at_stp_in_air

Unit: m-3
Unit ref: PCUM
The aerosol particle number size distribution is the number concentration of aerosol particles as a function of particle diameter. A coordinate variable with the standard name of electrical_mobility_particle_diameter, aerodynamic_particle_diameter, or optical_particle_diameter should be specified to indicate that the property applies at specific particle sizes selected by the indicated method. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. "log10_X" means common logarithm (i.e. base 10) of X. "stp" means standard temperature (0 degC) and pressure (101325 Pa).

log10_size_interval_based_number_size_distribution_of_aerosol_particles_in_air

Unit: m-3
Unit ref: PCUM
The aerosol particle number size distribution is the number concentration of aerosol particles, normalised to the decadal logarithmic size interval the concentration applies to, as a function of particle diameter. A coordinate variable with the standard name of electrical_mobility_particle_diameter, aerodynamic_particle_diameter, or optical_particle_diameter should be specified to indicate that the property applies at specific particle sizes selected by the indicated method. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. "log10_X" means common logarithm (i.e. base 10) of X.

log10_size_interval_based_number_size_distribution_of_cloud_condensation_nuclei_in_air

Unit: m-3
Unit ref: PCUM
The cloud condensation nuclei number size distribution is the number concentration of aerosol particles, normalised to the decadal logarithmic size interval the concentration applies to, as a function of particle diameter, where the particle acts as condensation nucleus for liquid-phase clouds. A coordinate variable with the standard name of relative_humidity should be specified to indicate that the property refers to a specific supersaturation with respect to liquid water. A coordinate variable with the standard name of electrical_mobility_particle_diameter should be specified to indicate that the property applies at specific mobility particle sizes. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. The ability of a particle to act as a condensation nucleus is determined by its size, chemical composition, and morphology. "log10_X" means common logarithm (i.e. base 10) of X.

thickness_of_soil_surface_organic_layer

Unit: m
Unit ref: ULAA
Depth or height of the organic soil horizon (O or H horizons per the World Reference Base soil classification system), measured from the soil surface down to the mineral horizon. Organic layers are commonly composed of a succession of litter of recognizable origin, of partly decomposed litter, and of highly decomposed (humic) organic material.

soil_density

Unit: kg m-3
Unit ref: UKMC
The density of the soil in its natural condition. Also known as bulk density. The density of a substance is its mass per unit volume.

compressive_strength_of_unconfined_frozen_soil

Unit: Pa
Unit ref: PASX
The maximum force applied as axial strain to an unconfined frozen soil sample before failure.

minimum_mass_ratio_of_water_to_dry_soil_for_soil_plastic_behavior

Unit: 1
Unit ref: UUUU
The phrase "ratio_of_X_to_Y" means X/Y. It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction. It is the lower limit of the water content at which a 3 mm diameter cylindrical soil sample will break in 3 to 10 mm pieces. It is the lower limit of the plastic state, which has the liquid limit as the upper bound. Known as the plastic limit.

frozen_soil_density

Unit: kg m-3
Unit ref: UKMC
The density of the soil in its naturally frozen condition. Also known as frozen bulk density. The density of a substance is its mass per unit volume.

compressive_strength_of_unconfined_soil

Unit: Pa
Unit ref: PASX
The maximum force applied as axial strain to an unconfined soil sample before failure.

density_ratio_of_dry_soil_to_water

Unit: 1
Unit ref: UUUU
The phrase "ratio_of_X_to_Y" means X/Y. It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction. Also known as specific gravity, where soil represents a dry soil sample. The density of a substance is its mass per unit volume.

acoustic_area_backscattering_strength_in_sea_water

Unit: 1
Unit ref: UUUU
Acoustic area backscattering strength is 10 times the log10 of the ratio of the area backscattering coefficient to the reference value, 1 (m2 m-2). Area backscattering coefficient is the integral of the volume backscattering coefficient over a defined distance. Volume backscattering coefficient is the linear form of acoustic_volume_backscattering_strength_in_sea_water. For further details see MacLennan et. al (2002) doi:10.1006/jmsc.2001.1158.

acoustic_volume_backscattering_strength_in_sea_water

Unit: 1
Unit ref: UUUU
Acoustic volume backscattering strength is 10 times the log10 of the ratio of the volume backscattering coefficient to the reference value, 1 m-1. Volume backscattering coefficient is the integral of the backscattering cross-section divided by the volume sampled. Backscattering cross-section is a parameter computed from the intensity of the backscattered sound wave relative to the intensity of the incident sound wave. The parameter is computed to provide a measurement that is proportional to biomass density per unit volume in the field of fisheries acoustics. For further details see MacLennan et. al (2002) doi:10.1006/jmsc.2001.1158.

acoustic_target_strength_in_sea_water

Unit: 1
Unit ref: UUUU
Target strength is 10 times the log10 of the ratio of backscattering cross-section to the reference value, 1 m2. Backscattering cross-section is a parameter computed from the intensity of the backscattered sound wave relative to the intensity of the incident sound wave. For further details see MacLennan et. al (2002) doi:10.1006/jmsc.2001.1158.

minimum_mass_ratio_of_water_to_dry_soil_for_soil_viscous_flow

Unit: 1
Unit ref: UUUU
The phrase "ratio_of_X_to_Y" means X/Y. It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction. It is the lower limit of the water content at which a soil sample will flow in a viscous manner. Known as the liquid limit.

ground_slope_direction

Unit: degree
Unit ref: UAAA
Commonly known as aspect, it is the azimuth (in degrees) of a terrain slope, taken as the direction with the greatest downslope change in elevation on the ground (earth) surface. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.

nfdrs_100_hour_fuel_moisture

Unit: %
Unit ref: UPCT
100 hour fuel moisture (FM100) represents the modeled moisture content of dead fuels in the 1 to 3 inch diameter class. It can also be used as a very rough estimate of the average moisture content of the forest floor from three-fourths inch to 4 inches below the surface. The 100-hour timelag fuel moisture is a function of length of day (as influenced by latitude and calendar date), maximum and minimum temperature and relative humidity, and precipitation duration in the previous 24 hours. It is a component in the US National Fire Danger Rating System. The US National Fire Danger Rating System comprises several numeric indexes that rate the potential over a large area for wildland fires to ignite, spread, and require action to suppress or manage. It was designed for use in the continental United States, and all its components are relative, not absolute.

volume_extinction_angstrom_exponent_in_air_due_to_ambient_aerosol_particles

Unit: 1
Unit ref: UUUU
The volume extinction Angstrom exponent is the Angstrom exponent obtained for the aerosol extinction instead that for the aerosol optical thickness. It is alpha in the following equation relating aerosol extinction (ext) at the wavelength lambda to aerosol extinction at a different wavelength lambda0: ext(lambda) = ext(lambda0) * [lambda/lambda0] ** (-1 * alpha). "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. 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.

surface_upward_mass_flux_of_methane_due_to_emission_from_fires

Unit: kg m-2 s-1
Unit ref: KSP2
Methane emitted from the surface, generated by biomass burning (fires). Positive direction upwards. The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. 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. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names. The term "fires" means all biomass fires, whether naturally occurring or ignited by humans. The precise conditions under which fires produce and consume methane can vary between models.

ratio_of_volume_extinction_coefficient_to_volume_backwards_scattering_coefficient_by_ranging_instrument_in_air_due_to_ambient_aerosol_particles

Unit: sr
The ratio of volume extinction coefficient to volume backwards scattering coefficient by ranging instrument in air due to ambient aerosol particles (often called "lidar ratio") is the ratio of the "volume extinction coefficient" and the "volume backwards scattering coefficient of radiative flux by ranging instrument in air due to ambient aerosol particles". The ratio is assumed to be related to the same wavelength of incident radiation. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. 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.

surface_upward_mass_flux_of_methane_due_to_emission_from_termites

Unit: kg m-2 s-1
Unit ref: KSP2
The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. 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. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names. Termites belong to any of a group of cellulose-eating insects, the social system of which shows remarkable parallels with those of ants and bees, although it has evolved independently. The precise conditions under which termites produce and consume methane can vary between models.

volume_backwards_scattering_coefficient_of_radiative_flux_by_ranging_instrument_in_air_due_to_ambient_aerosol_particles

Unit: m-1 sr-1
Unit ref: PMSR
Volume backwards scattering coefficient by ranging instrument is the fraction of radiative flux, per unit path length and per unit solid angle, scattered at 180 degrees angle respect to the incident radiation and obtained through ranging techniques like lidar and radar. Backwards scattering coefficient is assumed to be related to the same wavelength of incident radiation. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. 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.

shear_strength_of_soil

Unit: Pa
Unit ref: PASX
Shear strength is the amount of force applied to a normal plane required to bring the soil to failure along a tangential plane. Shear strength depends on the angle of friction and cohesion of the soil.

altitude_at_top_of_atmosphere_boundary_layer_defined_by_ambient_aerosol_particles_backwards_scattering_by_ranging_instrument

Unit: m
Unit ref: ULAA
The altitude at top of atmosphere boundary layer is the elevation above sea level of the top of the (atmosphere) planetary boundary layer. The phrase "defined_by" provides the information of the tracer used for identifying the atmospheric boundary layer top. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. "By ranging instrument" means that the backscattering is obtained through ranging techniques like lidar and radar.

mole_concentration_of_dissolved_organic_13C_in_sea_water

Unit: mol m-3
Unit ref: MLM3
The sum of dissolved organic carbon-13 component concentrations. "Mole concentration" means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "Organic carbon" describes a family of chemical species and is the term used in standard names for all species belonging to the family 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. "C" means the element carbon and "13C" is the stable isotope "carbon-13", having six protons and seven neutrons.

surface_downward_mass_flux_of_methane_due_to_non_wetland_soil_biological_consumption

Unit: kg m-2 s-1
Unit ref: KSP2
The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. 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. Non-wetland soils are all soils except for wetlands. Wetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season. The precise conditions under which non-wetland soils produce and consume methane can vary between models.

keetch_byram_drought_index

Unit: 1
Unit ref: UUUU
The Keetch Byram Drought Index (KBDI) is a numerical drought index ranging from 0 to 800 that estimates the cumulative moisture deficiency in soil. It is a cumulative index. It is a function of maximum temperature and precipitation over the previous 24 hours.

dry_soil_density

Unit: kg m-3
Unit ref: UKMC
The density of the soil after oven drying until constant mass is reached. Volume is determined from the field sample volume. The density of a substance is its mass per unit volume.

nfdrs_energy_release_component

Unit: J m-2
Unit ref: JMSQ
The Energy Release Component (ERC) is a number related to the available energy per unit area within the flaming front at the head of a fire. It is usually given in BTU ft-2. Daily variations in ERC are due to changes in moisture content of the various fuels present, both live and dead. It may also be considered a composite fuel moisture value as it reflects the contribution that all live and dead fuels have to potential fire intensity. Energy Release Component is a cumulative index. The scale is open-ended and relative. Energy Release Component values depend on the fuel model input into the calculations and interpretation of precise values varies with ecology and region. It is an index in the US National Fire Danger Rating System. The US National Fire Danger Rating System comprises several numeric indexes that rate the potential over a large area for wildland fires to ignite, spread, and require action to suppress or manage. It was designed for use in the continental United States, and all its components are relative, not absolute.

aerosol_type_in_atmosphere_layer_in_air

Unit: 1
Unit ref: UUUU
A variable with the standard_name of aerosol_type_in_atmosphere_layer_in_air contains either strings which indicate the type of the aerosol determined following a certain aerosol typing schema, or flags which can be translated to strings using flag_values and flag_meanings attributes. "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).

angstrom_exponent_of_volume_backwards_scattering_in_air_due_to_ambient_aerosol_particles

Unit: 1
Unit ref: UUUU
The Angstrom exponent of volume backwards scattering is the Angstrom exponent related only to the aerosol backwards scattering component. It is alpha in the following equation relating volume backwards scattering (back) at the wavelength lambda to volume backwards scattering at a different wavelength lambda0: back(lambda) = back(lambda0) * [lambda/lambda0] ** (-1 * alpha). "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. 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.

perceived_temperature

Unit: degree_C
Unit ref: UPAA
Perceived temperature (PT) is an equivalent air temperature of the actual thermal condition. It is the air temperature of a reference condition causing the same thermal perception in a human body considering air temperature, wind speed, humidity, solar and thermal radiation as well as clothing and activity level. It is not the perceived air temperature, that derives either from wind chill and heat index and has the standard_name apparent_air_temperature.

mass_ratio_of_moisture_to_dry_soil

Unit: 1
Unit ref: UUUU
The quantity with standard name mass_ratio_of_moisture_to_dry_soil is also known as the water content of a soil or the wet-basis gravimetric moisture content. It is the ratio of the mass of water (liquid and solid) to the mass of the dried sample. The phrase "ratio_of_X_to_Y" means X/Y. It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction.

altitude_at_top_of_atmosphere_mixed_layer_defined_by_ambient_aerosol_particles_backwards_scattering_by_ranging_instrument

Unit: m
Unit ref: ULAA
The altitude at top of atmosphere mixed layer is the elevation above sea level of the top of the (atmosphere) mixed layer or convective boundary layer. The phrase "defined_by" provides the information of the tracer used for identifying the atmospheric boundary layer top. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. "By ranging instrument" means that the volume backscattering coefficient is obtained through ranging techniques like lidar and radar.

ground_slope_angle

Unit: degree
Unit ref: UAAA
The slope angle is the angle (in degrees) measured between the ground (earth) surface plane and a flat, horizontal surface.

moles_of_particulate_inorganic_carbon_per_unit_mass_in_sea_water

Unit: mol kg-1
Unit ref: MLKG
The construction "moles_of_X_per_unit_mass_in_Y" is also called "molality" of X in Y, where X is a material constituent of Y. A chemical species or biological group denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". Particulate means suspended solids of all sizes. Particulate inorganic carbon is carbon bound in molecules ionically that may be liberated from the particles as carbon dioxide by acidification.

canadian_fire_weather_index

Unit: 1
Unit ref: UUUU
The Canadian Fire Weather Index (CFWI) is a numerical rating of potential frontal fire intensity from the Canadian Forest Fire Index System. It indicates fire intensity by combining the rate of spread with the amount of fuel being consumed and is also used for general public information about fire danger conditions. It is a function of wind speed, temperature, relative humidity, and precipitation. The calculation accounts for multiple layers of flammable material on the ground as well as fine fuels above the surface, combined with the expected rate of spread of fire. The index is open ended.

surface_upward_mass_flux_of_methane_due_to_emission_from_herbivorous_mammals

Unit: kg m-2 s-1
Unit ref: KSP2
The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. 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. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names. Herbivores are animals that feed on vegetation. Mammals are any vertebrates within the class Mammalia. Examples of large herbivorous mammals include cows, elks, and buffalos. These animals eat grass, tree bark, aquatic vegetation, and shrubby growth. Herbivores can also be medium-sized animals such as sheep and goats, which eat shrubby vegetation and grasses. Small herbivores include rabbits, chipmunks, squirrels, and mice. The precise conditions under which herbivorous mammals produce and consume methane can vary between models.

universal_thermal_climate_index

Unit: degree_C
Unit ref: UPAA
Universal Thermal Comfort Index (UTCI) is an equivalent temperature of the actual thermal condition. Reference: utci.org. It is the air temperature of a reference condition causing the same dynamic physiological response in a human body considering its energy budget, physiology and clothing adaptation.

vertical_drainage_amount_in_soil

Unit: kg m-2
Unit ref: KMP2
"Drainage" is the process of removal of excess water from soil by gravitational flow. "Amount" means mass per unit area. The vertical drainage amount in soil is the amount of water that drains through the bottom of a soil column extending from the surface to a specified depth.

cloud_type

Unit: 1
Unit ref: UUUU
A variable with the standard_name of cloud_type contains either strings which indicate the cloud type, or flags which can be translated to strings using flag_values and flag_meanings attributes.

nfdrs_1000_hour_fuel_moisture

Unit: %
Unit ref: UPCT
1000 hour fuel moisture (FM1000) represents the modelled moisture content in the dead fuels in the 3 to 8 inch diameter class and the layer of the forest floor about 4 inches below the surface. The value is based on a running 7-day average. The 1000-hour time lag fuel moisture is a function of length of day (as influenced by latitude and calendar date), daily temperature and relative humidity extremes (maximum and minimum values) and the 24-hour precipitation duration values for a 7-day period. It is a component in the US National Fire Danger Rating System. The US National Fire Danger Rating System comprises several numeric indexes that rate the potential over a large area for wildland fires to ignite, spread, and require action to suppress or manage. It was designed for use in the continental United States, and all its components are relative, not absolute.

nfdrs_severe_fire_danger_index

Unit: 1
Unit ref: UUUU
Severe Fire Danger Index (SFDI) is the normalized product of normalized Energy Release Component (ERC) and normalized Burning Index (BI) from the United States National Fire Danger Rating System (NFDRS). While SFDI is not officially part of the National Fire Danger Rating System, it is related to and intended to supplement NFDRS. It is commonly categorized into five classes based on percentile: low (0-60), moderate (60-80), high (80-90), very high (90-97), and extreme (97-100). It can be extended to future conditions by introducing an unprecedented category for values above the historical 100th percentile. As it is locally normalized, its interpretation remains the same across space.

modified_fosberg_fire_weather_index

Unit: 1
Unit ref: UUUU
The modified Fosberg Fire Weather Index (mFFWI) is a measure of the potential effect of weather conditions on wildland fire. The Fosberg Fire Weather Index is a function of temperature, wind, and humidity. It is modified with a fuel availability factor based on the Keetch Byram Drought Index.

soil_water_salinity

Unit: 1e-3
Unit ref: UUUU
The quantity with standard name soil_water_salinity is the salt content of soil 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.

physiological_equivalent_temperature

Unit: degree_C
Unit ref: UPAA
Physiological equivalent temperature (PET) is an equivalent air temperature of the actual thermal condition. It is the air temperature of a reference condition without wind and solar radiation at which the heat budget of the human body is balanced with the same core and skin temperature. Note that PET here is not potential evapotranspiration.

shear_strength_of_frozen_soil

Unit: Pa
Unit ref: PASX
Shear strength is the amount of force applied to a normal plane required to bring a frozen soil to failure along a tangential plane. Shear strength depends on the angle of friction and cohesion of the soil.

nfdrs_burning_index

Unit: 1
Unit ref: UUUU
The Burning Index (BI) is a numeric value closely related to the flame length in feet multiplied by 10, which is related to the contribution of fire behaviour to the effort of containing a fire. The BI is a function of fire spread and fire intensity and is derived from a combination of Spread and Energy Release Components. The Spread Component is a rating of the forward rate of spread of a head fire and wind is a key input. The scale is open ended which allows the range of numbers to adequately define fire problems, even in time of low to moderate fire danger. Computed BI values represent the near upper limit to be expected on the rating area. In other words, if a fire occurs in the worst fuel, weather and topography conditions of the rating area, these numbers indicate its expected fire line intensities and flame length. It is an index in the US National Fire Danger Rating System. The US National Fire Danger Rating System comprises several numeric indexes that rate the potential over a large area for wildland fires to ignite, spread, and require action to suppress or manage. It was designed for use in the continental United States, and all its components are relative, not absolute.

number_size_distribution_of_cloud_condensation_nuclei_at_stp_in_air

Unit: m-3
Unit ref: PCUM
The cloud condensation nuclei number size distribution is the number concentration of aerosol particles as a function of particle diameter, where the particle acts as condensation nucleus for liquid-phase clouds. A coordinate variable with the standard name of relative_humidity should be specified to indicate that the property refers to a specific supersaturation with respect to liquid water. A coordinate variable with the standard name of electrical_mobility_particle_diameter should be specified to indicate that the property applies at specific mobility particle sizes. To specify the relative humidity at which the particle sizes were selected, provide a scalar coordinate variable with the standard name of relative_humidity_for_aerosol_particle_size_selection. The ability of a particle to act as a condensation nucleus is determined by its size, chemical composition, and morphology. "stp" means standard temperature (0 degC) and pressure (101325 Pa).