## Contents

Name | Notation | Description | Types | Status |
---|---|---|---|---|

minute (angle) | ' | Unit of plane or phase angle, accepted for use with SI: 1 ' =... | Concept | stable |

second (angle) | '' | Unit of plane or phase angle, accepted for use with SI: 1 '' ... | Concept | stable |

parts per thousand | 0.001 | Concept | superseded | |

dimensionless | 1 | Dimensionless; SI base unit equivalent: 1 | Concept | stable |

ampere | A | SI base unit of electric current | Concept | stable |

astronomical unit | AU | Unit of length, accepted for use with SI: 1 AU = 149597870700... | Concept | stable |

becquerel | Bq | SI derived unit of radioactivity; SI base unit equivalent: s-... | Concept | stable |

becquerel per litre | Bq.l-1 | Unit of radioactivity concentration; SI base unit equivalent:... | Concept | stable |

becquerel per square metre | Bq.m-2 | SI derived unit of radioactivity area concentration; SI base ... | Concept | stable |

becquerel per cubic metre | Bq.m-3 | SI derived unit of radioactivity concentration; SI base unit ... | Concept | stable |

becquerel second per cubic metre | Bq.s.m-3 | SI derived unit of time integrated radioactivity concentratio... | Concept | stable |

becquerels per litre | Bq_l-1 | Concept | superseded | |

becquerels per square metre | Bq_m-2 | Concept | superseded | |

becquerels per cubic metre | Bq_m-3 | Concept | superseded | |

becquerel seconds per cubic metre | Bq_s_m-3 | Concept | superseded | |

coulomb | C | SI derived unit of electric charge; SI base unit equivalent: ... | Concept | stable |

colony-forming unit per millilitre | CFU.ml-1 | Unit of number concentration of viable bacteria or fungal cel... | Concept | stable |

degrees Celsius per 100 metres | C_(100m)-1 | Concept | superseded | |

degrees Celsius per metre | C_m-1 | Concept | superseded | |

degree Celsius | Cel | Concept | superseded | |

Dobson Unit | DU | Unit of column abundance of molecules in the atmosphere. 1 DU... | Concept | stable |

Eötvös | E | Unit of acceleration divided by distance,1 E = 1E-9 Gal/cm; S... | Concept | stable |

farad | F | SI derived unit of electrical capacitance; SI base unit equiv... | Concept | stable |

gigahertz | GHz | SI derived unit of frequency; SI base unit equivalent: 1E9 s-... | Concept | stable |

gray | Gy | SI derived unit of absorbed dose (of ionizing radiation); SI ... | Concept | stable |

henry | H | SI derived unit of electrical inductance; SI base unit equiva... | Concept | stable |

Hazen unit | HU | Unit of color according to the Platinum/Cobalt or Apha-Hazen ... | Concept | stable |

hertz | Hz | SI derived unit of frequency; SI base unit equivalent: s-1 | Concept | stable |

joule | J | SI derived unit of energy, work, heat; SI base unit equivalen... | Concept | stable |

joule per kilogram | J.kg-1 | SI derived unit of specific energy or specific potential enth... | Concept | stable |

joule per square metre | J.m-2 | SI derived unit of radiant exposure; SI base unit equivalent:... | Concept | stable |

joules per kilogram | J_kg-1 | Concept | superseded | |

joules per square metre | J_m-2 | Concept | superseded | |

kelvin | K | SI base unit of thermodynamic temperature | Concept | stable |

kelvin per metre | K.m-1 | SI derived unit of spatial gradient of temperature | Concept | stable |

kelvin metre per second | K.m.s-1 | SI derived unit of covariance of wind speed and temperature o... | Concept | stable |

kelvin square metre per kilogram per second | K.m2.kg-1.s-1 | SI derived unit of potential vorticity | Concept | stable |

kelvins per metre | K_m-1 | Concept | superseded | |

kelvin square metres per kilogram per second | K_m2_kg-1_s-1 | Concept | superseded | |

kelvin metres per second | K_m_s-1 | Concept | superseded | |

megahertz | MHz | SI derived unit of frequency; SI base unit equivalent: 1E6 s-... | Concept | stable |

most probable number index number in 1 millilitre | MPN.ml-1 | Unit of expected number concentration of bacteria in the orig... | Concept | stable |

per megametre | Mm-1 | Unit of quantity with dimension of reciprocal length, e.g., o... | Concept | stable |

per megametre per steradian | Mm-1.sr-1 | SI derived unit of the scattering coefficient at a given dire... | Concept | stable |

newton | N | SI derived unit of force, weight | Concept | stable |

newton per square metre | N.m-2 | SI derived unit of pressure or equivalent quantity | Concept | stable |

nephelometric turbidity unit | NTU | Units of turbidity from a calibrated nephelometer; SI base un... | Concept | stable |

newtons per square metre | N_m-2 | Concept | superseded | |

N units | N_units | Unit of atmospheric refractivity, the refractivity, N, is rel... | Concept | stable |

ohm | Ohm | SI derived unit of electrical resistance, impedance, reactanc... | Concept | stable |

pascal | Pa | SI derived unit of pressure/stress; SI base unit equivalent: ... | Concept | stable |

pascal per second | Pa.s-1 | SI derived unit of temporal derivative of pressure/stress; SI... | Concept | stable |

pascals per second | Pa_s-1 | Concept | superseded | |

siemens | S | SI derived unit of electrical conductance; SI base unit equiv... | Concept | stable |

siemens per metre | S.m-1 | SI derived unit of spatial gradient of electric conductance | Concept | stable |

siemens per metre | S_m-1 | Concept | superseded | |

sievert | Sv | SI derived unit of equivalent dose (of ionizing radiation); S... | Concept | stable |

tesla | T | SI derived unit of magnetic induction, magnetic flux density;... | Concept | stable |

terahertz | THz | SI derived unit of frequency; SI base unit equivalent: 1E12 s... | Concept | stable |

volt | V | SI derived unit of voltage, electrical potential difference, ... | Concept | stable |

watt | W | SI derived unit of power, radiant flux; SI base unit equivale... | Concept | stable |

watt per metre per steradian | W.m-1.sr-1 | SI derived unit of spectral intensity, a directional quantity... | Concept | stable |

watt per square metre | W.m-2 | SI derived unit of heat flux density or irradiance; SI base u... | Concept | stable |

watt per square metre per steradian | W.m-2.sr-1 | SI derived unit of radiance; SI base unit equivalent: kg.s-3 | Concept | stable |

watt per square metre per steradian per hertz | W.m-2.sr-1.Hz-1 | SI derived unit of spectral radiance per unit frequency; SI b... | Concept | stable |

watt per square metre per steradian per inverse centimetre | W.m-2.sr-1.cm | SI derived unit of spectral radiance per unit wavenumber, wav... | Concept | stable |

watt per square metre per steradian per inverse metre | W.m-2.sr-1.m | SI derived unit of spectral radiance per inverse metre; SI ba... | Concept | stable |

watt per square metre per steradian per metre | W.m-3.sr-1 | SI derived unit of spectral radiance per unit wavelength; SI ... | Concept | stable |

watts per metre per steradian | W_m-1_sr-1 | Concept | superseded | |

watts per square metre | W_m-2 | Concept | superseded | |

watts per square metre per steradian | W_m-2_sr-1 | Concept | superseded | |

watts per square metre per steradian centimetre | W_m-2_sr-1_cm | Concept | superseded | |

watts per square metre per steradian metre | W_m-2_sr-1_m | Concept | superseded | |

watts per cubic metre per steradian | W_m-3_sr-1 | Concept | superseded | |

Weber | Wb | SI derived unit of magnetic flux; SI base unit equivalent: kg... | Concept | stable |

year | a | Conventional unit of time duration, ranging from 365 days to ... | Concept | stable |

centibar per 12 hours | cb.(12h)-1 | Conventional unit of time derivative of pressure, pressure te... | Concept | stable |

centibar per second | cb.s-1 | Conventional unit of time derivative of pressure, pressure te... | Concept | stable |

centibars per 12 hours | cb_-1 | Concept | superseded | |

centibars per second | cb_s-1 | Concept | superseded | |

candela | cd | SI base unit of luminous intensity | Concept | stable |

centimetre | cm | SI prefixed unit of length; SI base unit equivalent: 0.01 m | Concept | stable |

per cubic centimetre | cm-3 | SI derived unit of specific volume; SI base unit equivalent: ... | Concept | stable |

centimetre per hour | cm.h-1 | SI derived unit of speed; SI base unit equivalent: 1/360000 m... | Concept | stable |

centimetre per second | cm.s-1 | SI derived unit of speed; SI base unit equivalent: 0.01 m.s-1 | Concept | stable |

square centimetre | cm2 | SI derived unit of area; SI base unit equivalent: 1E-4 m2 | Concept | stable |

cubic centimetre per cubic metre | cm3.m-3 | SI derived unit of volumetric mixing ratio, equivalent to ppm... | Concept | stable |

centimetres per hour | cm_h-1 | Concept | superseded | |

centimetres per second | cm_s-1 | Concept | superseded | |

day | d | Unit of time, accepted for use with SI: 1 d = 86400 s | Concept | stable |

decibel | dB | Unit of sound intensity, accepted for use with SI | Concept | stable |

decibel per degree (angle) | dB.deg-1 | Unit of angular gradient of sound intensity | Concept | stable |

decibel per metre | dB.m-1 | Unit of spatial gradient of sound intensity | Concept | stable |

decibels per degree | dB_deg-1 | Concept | superseded | |

decibels per metre | dB_m-1 | Concept | superseded | |

decipascal per second (microbar per second) | dPa.s-1 | SI derived unit of time derivative of pressure, pressure tend... | Concept | stable |

decipascals per second (microbar per second) | dPa_s-1 | Concept | superseded | |

dekapascal | daPa | SI derived unit of pressure/stress; SI base unit equivalent: ... | Concept | stable |

degree (angle) | deg | Unit of plane or phase angle, accepted for use with SI: 1 deg... | Concept | stable |

degree (angle) per second | deg.s-1 | Unit of angular speed, accepted for use with SI | Concept | stable |

square degree (angle) | deg2 | Unit of square of phase or plane angle, accepted for use with... | Concept | stable |

degree Celsius (°C) | degC | SI derived unit of temperature, as defined by ITS-90; SI base... | Concept | stable |

degree Celsius per 100 metres | degC.hm-1 | SI derived unit of spatial gradient of temperature per 100 me... | Concept | stable |

degree Celsius per metre | degC.m-1 | SI derived unit of spatial gradient of temperature per metre;... | Concept | stable |

degrees per second | deg_s-1 | Concept | superseded | |

degree (angle) | degree_(angle) | Concept | superseded | |

degrees true | degrees_true | Concept | superseded | |

decimetre | dm | SI prefixed unit of length; SI base unit equivalent: 0.1 m | Concept | stable |

electron volt | eV | Unit of energy, accepted for use with SI; SI base unit equiva... | Concept | stable |

femtomole per kilogram | fmol.kg-1 | SI derived unit of amount per unit mass; SI base unit equival... | Concept | stable |

foot | ft | Imperial/US unit of length, equal to 1200/3937 metre or 0.304... | Concept | stable |

acceleration due to gravity | g | Concept | superseded | |

gram per cubic centimetre | g.cm-3 | SI derived unit of density, equivalent to kilograms per litre... | Concept | stable |

gram per kilogram | g.kg-1 | SI derived unit of mass fraction, dimensionless; SI base unit... | Concept | stable |

gram per kilogram per second | g.kg-1.s-1 | SI derived unit of time derivative of mass fraction; SI base ... | Concept | stable |

standard acceleration due to gravity | g0 | Conventional unit of gravity acceleration; g0 = 9.80665 m.s-2 | Concept | stable |

grams per kilogram | g_kg-1 | Concept | superseded | |

grams per kilogram per second | g_kg-1_s-1 | Concept | superseded | |

geopotential metre | gpm | The height of a given point in the atmosphere in units propor... | Concept | stable |

hour | h | Unit of time, accepted for use with SI: 1 h = 3600 s | Concept | stable |

hectopascal | hPa | SI derived unit of pressure/stress; SI base unit equivalent: ... | Concept | stable |

hectopascal per 3 hours | hPa.(3h)-1 | SI derived unit of time derivative of pressure; SI base unit ... | Concept | stable |

hectopascal per hour | hPa.h-1 | SI derived unit of time derivative of pressure; SI base unit ... | Concept | stable |

hectopascal per second | hPa.s-1 | SI derived unit of time derivative of pressure; SI base unit ... | Concept | stable |

hectopascals per 3 hours | hPa_-1 | Concept | superseded | |

hectopascals per hour | hPa_h-1 | Concept | superseded | |

hectopascals per second | hPa_s-1 | Concept | superseded | |

hectare | ha | Unit of area, accepted for use with SI: 1 ha = 1E4 m2 | Concept | stable |

inch | in | Imperial/US unit of length, equal to 25.4 millimetres | Concept | stable |

inapplicable | inapplicable | There is no value (categorical data) | Concept | stable |

kilohertz | kHz | SI derived unit of frequency; SI base unit equivalent: 1000 s... | Concept | stable |

kilopascal | kPa | SI derived unit of pressure/stress, equal to 1000 Pa; SI base... | Concept | stable |

kilocalory per square centimetre | kcal.cm-2 | Unit of radiant exposure, equal to 4.184E7 J.m-2 | Concept | stable |

kilogram | kg | SI base unit of mass | Concept | stable |

per square kilogram per second | kg-2.s-1 | SI derived unit of quantity with dimension of M-2.T-1 | Concept | stable |

per square kilogram per second | kg-2_s-1 | Concept | superseded | |

kilogram per kilogram | kg.kg-1 | SI derived unit of mass fraction; SI base unit equivalent: 1 | Concept | stable |

kilogram per kilogram per second | kg.kg-1.s-1 | SI derived unit of time derivative of mass fraction; SI base ... | Concept | stable |

kilogram per metre | kg.m-1 | SI derived unit of linear mass density or quantity with dimen... | Concept | stable |

kilogram per square metre | kg.m-2 | SI derived unit of area density | Concept | stable |

kilogram per square metre per second | kg.m-2.s-1 | SI derived unit of time derivative of mass area density | Concept | stable |

kilogram per cubic metre | kg.m-3 | SI derived unit of density, mass density | Concept | stable |

kilograms per kilogram | kg_kg-1 | Concept | superseded | |

kilograms per kilogram per second | kg_kg-1_s-1 | Concept | superseded | |

kilograms per metre | kg_m-1 | Concept | superseded | |

kilograms per square metre | kg_m-2 | Concept | superseded | |

kilograms per square metre per second | kg_m-2_s-1 | Concept | superseded | |

kilograms per cubic metre | kg_m-3 | Concept | superseded | |

kilometre | km | SI prefixed unit of length; SI base unit equivalent: 1000 m | Concept | stable |

per kilometre | km-1 | SI derived unit of quantity with dimension of reciprocal leng... | Concept | stable |

per kilometre per steradian | km-1.sr-1 | SI derived unit of the scattering coefficient at a given dire... | Concept | stable |

kilometre per day | km.d-1 | SI derived unit of speed; SI base unit equivalent: 1000/86400... | Concept | stable |

kilometre per hour | km.h-1 | SI derived unit of speed; SI base unit equivalent: 1000/3600 ... | Concept | stable |

kilometres per day | km_d-1 | Concept | superseded | |

kilometres per hour | km_h-1 | Concept | superseded | |

knot | kt | Conventional unit of speed, equal to 1 nmi/h; SI base unit eq... | Concept | stable |

knot per 1000 metres | kt.km-1 | Conventional unit of spatial gradient of speed; SI base unit ... | Concept | stable |

knots per 1000 metres | kt_km-1 | Concept | superseded | |

litre | l | SI derived unit of volume; SI base unit equivalent: 0.001 m3 | Concept | stable |

lumen | lm | SI derived unit of luminous flux; SI base unit equivalent: 1 ... | Concept | stable |

lux | lx | SI derived unit of illuminance; SI base unit equivalent: cd.m... | Concept | stable |

metre | m | SI base unit of length | Concept | stable |

metre to the two thirds power per second | m(2.3-1).s-1 | SI derived unit of the quantity with dimension of L^(2/3) T-1 | Concept | stable |

metres to the two thirds power per second | m(2_3)_s-1 | Concept | superseded | |

per metre | m-1 | SI derived unit of quantity with dimension of reciprocal leng... | Concept | stable |

per metre per steradian | m-1.sr-1 | SI derived unit of the scattering coefficient at a given dire... | Concept | stable |

per cubic metre | m-3 | SI derived unit of specific volume | Concept | stable |

metre per year | m.a-1 | Conventional unit of velocity | Concept | stable |

metre per second | m.s-1 | SI derived unit of speed | Concept | stable |

metre per second per 1000 metres | m.s-1.km-1 | SI derived unit of spatial gradient of speed; SI base unit eq... | Concept | stable |

metre per second per metre | m.s-1.m-1 | SI derived unit of spatial gradient of speed | Concept | stable |

metre per second squared | m.s-2 | SI derived unit of acceleration | Concept | stable |

square metre | m2 | SI derived unit of area | Concept | stable |

square metre second | m2.s | SI derived unit of sea surface wave variance spectral density | Concept | stable |

square metre per second | m2.s-1 | SI derived unit of kinematic viscosity, thermal diffusivity, ... | Concept | stable |

square metre per square second | m2.s-2 | SI derived quantity with dimension of squared speed | Concept | stable |

square metre second per radian | m2.s.rad-1 | SI derived unit of sea surface wave directional variance spec... | Concept | stable |

square metres per hertz | m2_Hz-1 | Concept | superseded | |

square metres per radian second | m2_rad-1_s | Concept | superseded | |

square metres second | m2_s | Concept | superseded | |

square metres per second | m2_s-1 | Concept | superseded | |

square metres per second squared | m2_s-2 | Concept | superseded | |

cubic metres | m3 | SI derived unit of volume | Concept | stable |

cubic metre per cubic metre | m3.m-3 | SI derived unit of volume fraction; SI base unit equivalent: ... | Concept | stable |

cubic metre per second | m3.s-1 | SI derived unit of volume flow rate or time derivative of vol... | Concept | stable |

cubic metres per cubic metre | m3_m-3 | Concept | superseded | |

cubic metres per second | m3_s-1 | Concept | superseded | |

metre to the fourth power | m4 | SI derived unit of the second moment of area, area moment of ... | Concept | stable |

millibecquerel per cubic metre | mBq.m-3 | SI derived unit of volumetric radioactivity concentration; SI... | Concept | stable |

millibecquerels per cubic metre | mBq_m-3 | Concept | superseded | |

milligal | mGal | CGS unit of acceleration, equal to one thousandth of a Gal (1... | Concept | stable |

millisiemens per centimetre | mS.cm-1 | SI derived unit of spatial gradient of electrical conductance... | Concept | stable |

millisievert | mSv | SI derived unit of equivalent dose (of ionizing radiation); S... | Concept | stable |

millivolt | mV | SI derived unit of voltage, electrical potential difference, ... | Concept | stable |

metres per second | m_s-1 | Concept | superseded | |

metres per second per 1000 metres | m_s-1_km-1 | Concept | superseded | |

metres per second per metre | m_s-1_m-1 | Concept | superseded | |

metres per second squared | m_s-2 | Concept | superseded | |

millibar | mbar | Conventional unit of pressure, equal to 1 hPa; SI base unit e... | Concept | stable |

milligram per cubic centimetre | mg.cm-3 | SI derived unit of mass concentration; SI base unit equivalen... | Concept | stable |

milligram per kilogram | mg.kg-1 | SI derived unit of mass fraction, equivalent to ppmm (parts p... | Concept | stable |

milligram per litre | mg.l-1 | SI derived unit of density or mass concentration; SI base uni... | Concept | stable |

milligram per cubic metre | mg.m-3 | SI derived unit of density or mass concentration; SI base uni... | Concept | stable |

milligram N per litre | mg_N_l-1 | Concept | superseded | |

milligram S per litre | mg_S_l-1 | Concept | superseded | |

milligrams per cubic metre at 25 degrees | mg_m-3_25C | Concept | superseded | |

minute (time) | min | Unit of time, accepted for use with SI: 1 min = 60 s | Concept | stable |

missing | missing | The correct value is not readily available to the sender of t... | Concept | stable |

millimetre | mm | SI prefixed unit of length; SI base unit equivalent: 0.001 m | Concept | stable |

millimetre per hour | mm.h-1 | SI derived unit of speed; SI base unit equivalent: 1/3.6E6 m.... | Concept | stable |

millimetre per second | mm.s-1 | SI derived unit of speed; SI base unit equivalent: 0.001 m.s-... | Concept | stable |

cubic millimetre per cubic metre | mm3.m-3 | SI derived unit of volumetric mixing ratio, equivalent to ppb... | Concept | stable |

millimetre to the sixth power per cubic metre | mm6.m-3 | SI derived unit of quantity with dimension of L3; SI base uni... | Concept | stable |

millimetres to the sixth power per cubic metre | mm6_m-3 | Concept | superseded | |

millimetre of mercury | mmHg | Conventional unit of pressure, equal to 133.322387415 Pa | Concept | stable |

millimetres per hour | mm_h-1 | Concept | superseded | |

millimetres per second | mm_s-1 | Concept | superseded | |

millimole per mole | mmol.mol-1 | SI derived unit equivalent to expressing mole fraction in par... | Concept | stable |

millimoles per mole | mmol_mol-1 | Concept | superseded | |

mole | mol | SI base unit of amount of substance | Concept | stable |

mole per mole | mol.mol-1 | SI derived unit of mole fraction; SI base unit equivalent: 1 | Concept | stable |

moles per mole | mol_mol-1 | Concept | superseded | |

month | mon | Conventional unit of time duration of between 28-31 days wher... | Concept | stable |

nautical mile | nautical_mile | Concept | superseded | |

nanobar | nbar | Conventional unit of pressure; SI base unit equivalent: 1E-4 ... | Concept | stable |

nanogram per kilogram | ng.kg-1 | SI derived unit of mass fraction, equivalent to pptm (parts p... | Concept | stable |

nanogram per cubic metre | ng.m-3 | SI derived unit of mass concentration; SI base unit equivalen... | Concept | stable |

nanograms per cubic metre | ng_m-3 | Concept | superseded | |

nanometre | nm | SI prefixed unit of length; SI base unit equivalent: 1E-9 m | Concept | stable |

nautical mile | nmi | Conventional unit of length; SI base unit equivalent: 1852 m | Concept | stable |

nanomole per kilogram | nmol.kg-1 | SI derived unit of amount per unit mass; SI base unit equival... | Concept | stable |

nanomole per mole | nmol.mol-1 | SI derived unit of mole fraction; SI base unit equivalent: 1E... | Concept | stable |

nanomoles per mole | nmol_mol-1 | Concept | superseded | |

eights of sky covered by cloud | okta | Unit of cloud amount, expressed as number of eighths of the s... | Concept | stable |

pH unit | pH_unit | Negative decimal logarithm of the hydrogen ion activity ('eff... | Concept | stable |

parsec | pc | Astronomical unit of length, 1 pc = 64800/Π AU | Concept | stable |

per cent | percent | Dimensionless number, expressed as a fraction of 100; SI base... | Concept | stable |

per meg | permeg | Dimensionless number, expressed as a fraction of 1000000; SI ... | Concept | stable |

per mille | permil | Dimensionless number, expressed as a fraction of 1000; SI bas... | Concept | stable |

picomole per kilogram | pmol.kg-1 | SI derived unit of amount per unit mass; SI base unit equival... | Concept | stable |

picomole per mole | pmol.mol-1 | SI derived unit equivalent of mole fraction; SI base unit equ... | Concept | stable |

picomoles per mole | pmol_mol-1 | Concept | superseded | |

parts per billion by volume | ppbv | Unit of volume fraction, equivalent to SI derived unit: 1E-9 | Concept | stable |

parts per million by volume | ppmv | Unit of volume fraction, equivalent to SI derived unit: 1E-6 | Concept | stable |

parts per trillion by volume | pptv | Unit of volume fraction, equivalent to SI derived unit: 1E-12 | Concept | stable |

practical salinity unit | psu | Conventional unit, equivalent to per mille; SI based unit equ... | Concept | stable |

radian | rad | SI derived unit of plane angle; SI base unit equivalent: 1 | Concept | stable |

radian per metre | rad.m-1 | SI derived unit of spatial gradient of plane angle | Concept | stable |

radian per second | rad.s-1 | SI derived unit of angular velocity; SI base unit equivalent:... | Concept | stable |

radians per metre | rad_m-1 | Concept | superseded | |

radian per second | rad_s-1 | Concept | superseded | |

second | s | SI base unit of time | Concept | stable |

per second (same as hertz) | s-1 | Concept | superseded | |

per second squared | s-2 | SI derived unit of second order time derivative | Concept | stable |

second per metre | s.m-1 | SI derived unit of quantity with dimension of T.L-1 | Concept | stable |

seconds per metre | s_m-1 | Concept | superseded | |

steradian | sr | SI derived unit of solid angle; SI base unit equivalent: 1 | Concept | stable |

tonne | t | Unit of mass, accepted for use with SI; SI base unit equivale... | Concept | stable |

(metric) ton per hectare | t.ha-1 | Unit of area density, equal to 0.1 kg.m-2 | Concept | stable |

(metric) ton per hectare | t_ha-1 | Concept | superseded | |

unified atomic mass unit | u | Conventional unit of mass; 1 u = 1 Da (Dalton) = 1.6605390666... | Concept | stable |

microsiemens per centimetre | uS.cm-1 | SI derived unit of spatial gradient of electrical conductance... | Concept | stable |

microgram per kilogram | ug.kg-1 | SI derived unit of mass fraction, equivalent to ppbm (parts p... | Concept | stable |

microgram per litre | ug.l-1 | SI derived unit of mass concentration; SI base unit equivalen... | Concept | stable |

microgram per cubic metre | ug.m-3 | SI derived unit of mass concentration; SI base unit equivalen... | Concept | stable |

microgram C per cubic metre | ug_C_m-3 | Concept | superseded | |

microgram CI per cubic metre | ug_Cl_m-3 | Concept | superseded | |

microgram N per cubic metre | ug_N_m-3 | Concept | superseded | |

microgram S per cubic metre | ug_S_m-3 | Concept | superseded | |

micrograms per cubic metre at 20 degrees | ug_m-3_20C | Concept | superseded | |

micrograms per cubic metre at 25 degrees | ug_m-3_25C | Concept | superseded | |

micrometre | um | SI prefixed unit of length; SI base unit equivalent: 1E-6 m | Concept | stable |

cubic micrometre per cubic centimetre | um3.cm-3 | SI derived unit of volume fraction, equivalent to pptv (parts... | Concept | stable |

micromole per kilogram | umol.kg-1 | SI derived unit of amount per unit mass; SI base unit equival... | Concept | stable |

micromole per litre | umol.l-1 | SI derived unit of amount concentration; SI base unit equival... | Concept | stable |

micromole per mole | umol.mol-1 | SI derived unit of mole fraction; SI base unit equivalent: 1E... | Concept | stable |

micromoles per kilogram | umol_kg-1 | Concept | superseded | |

micromoles per litre | umol_l-1 | Concept | superseded | |

micromoles per mole | umol_mol-1 | Concept | superseded | |

unknown | unknown | The correct value is not known to, and not computable by, the... | Concept | stable |

week | week | Conventional unit of time, equivalent to 604800 s | Concept | stable |