A

AAOE - Airborne Antarctic Ozone Experiment

AASE - Airborne Arctic Stratospheric Expedition

AATSR - Advanced Along-Track Scanning Radiometer

ABLE - Atmospheric Boundary Layer Experiment

ACATS - Airborne Chromatograph For Atmospheric Trace Species

ACCENT - Atmospheric Chemistry of Combustion Emissions Near the Tropopause

ACE-FTS - Fourier Transform Spectrometer (ACE-FTS) flown on SCISAT

ACE-Asia - Aerosol Characterization Experiment - Asia

ACMAP - Atmospheric Chemistry Modeling and Analysis Program

ACR - Active Cavity Radiometer

ACRIM - Active Cavity Radiometer Irradiance Monitor

ACSYS - Arctic Climate SYstem Study

ADALT - Advanced Radar Altimeter

ADEOS - Advanced Earth Observing Satellite (Japan)

AE - Atmospheric Explorer

AEAP - NASA's Atmospheric Effects of Aviation Project

AER - Atmospheric and Environmental Research

AES - Atmospheric Environment Service (Canada)

AESA - Atmospheric Effects of Stratospheric Aircraft program

AFGL - Air Force Geophysics Laboratory

AFGWC - Air Force Global Weather Central

AFRL - Air Force Research Laboratory (USA)

AGAGE - Advanced Global Atmospheric Gases Experiment

AGU - American Geophysical Union

AIAA - American Institute of Aeronautics and Astronautics (USA)

AIDAA - Associazione Italiana Di Aeronautica e Astronautica

AIRS - Atmospheric InfraRed Sounder

AIS - Airborne Imaging Spectrometer

aldehyde - Organic chemical compound derived from the oxidation of primary alcohols, having the common group CHO. Used in manufacturing of dyes, resins, and organic acids.

ALE-GAGE - Atmospheric Lifetime Experiment-Global Atmospheric Gases Experiment

ALIAS - Aircraft Laser Infrared Absorption Spectrometer

AM - Ante meridiem (Latin: before midday), morning

AMRIR - Advanced Medium Resolution Imaging Radiometer

AMS - American Meteorological Society

AMSU-A - Advanced Microwave Sounding Unit-A

AMTS - Advanced Moisture and Temperature Sounder

anthropogenic - Involving the impact of man on the natural environment.

AO - Atomic Oxygen

API - Application-Program Interface

APS - Active Pixel Sensor

ARC - Ames Research Center

ARGOS - Argos Data Collection and Location System (France)

ARISTOTELES - Applications and Research Involving Space Technologies Observing The Earth's field from a Low Earth orbiting Satellite

ARL - Airborne Raman Lidar (flown on DC-8 aircraft), measures methane, water vapor, and temperature

ARM - Atmospheric Radiation Measurement program

AROTEL - Airborne Raman, Ozone, Temperature and Aerosol Lidar (flown on DC-8 aircraft)

ASCII - American Standard Code for Information Interchange

ASHOE/MAESA - Airborne Southern Hemisphere Ozone Experiment and Measurements for Assessing the Effects of Stratospheric Aircraft

ASI - Agenzia Spaziale Italiana

ATLAS - Airborne Tunable Laser Absorption Spectrometer

ATLID - ATmospheric LIDar

ATMOS - Atmospheric Trace Molecules Observed by Spectroscopy

ATOVS - Advanced TIROS Operational Vertical Sounder

ATS - Applications Technology Satellite

ATSR - Along Track Scanning Radiometer

AU - Astronomical Unit

AWIPS-90 - Advanced Weather Interactive Processing System for the 90's

B

BADC - British Atmospheric Data Centre

BAS - British Antarctic Survey

BIRA/IASB - Belgian Institue for Space Aeronomy

BLISS - Balloon-borne laser in-situ sensor

BMLS - Balloon microwave limb sounder

BNSC - British National Space Centre

Brewer Spectrophotometer - a Canadian ground-based instrument that measures the amount of ozone in the atmosphere. The Brewer Total Ozone Spectrophotometer operates at ground level, automatically tracking the sun and reading wavelengths at 5 different wavelengths between 306 and 320 nm that are absorbed by ozone, sulphur dioxide and nitrogen dioxide. Over 165 Brewers are in operation in 43 countries and Antarctica.

BOIC - Balloon Ozone Intercomaprison Campaign

bromine (Br) - Deep red, corrosive, nonmetallic, liquid halogen that gives off an irritating reddish brown vapor. Element of halons, used in pesticides and fire extinguishers.

BUV - Backscatter Ultraviolet Spectrometer

C

carbon dioxide (CO₂) - Odorless, colorless, incombustible, nontoxic gas that is produced during respiration, decomposition of organic material, and combustion. Important "greenhouse" gas that contributes to global warming by allowing solar radiation to pass through the atmosphere and trapping radiant heat reflected from Earth's surface.

carbon monoxide (CO) - Poisonous, odorless, colorless gas, produced by incomplete combustion of gasoline and diesel fuels.

carbon oxides - Compounds containing carbon and oxygen.

CAS -Chinese Academy of Sciences (China)

CAST -Chinese Academy of Space Technology (China)

CCD - Charged Coupled Device

CCRS -Canada Centre for Remote Sensing (Canada)

CCSDS -Consultative Committee for Space Data Systems

CEOS - Committee on Earth Observation Satellites

CFC-11 (CFCl3) - Halocarbon compound used in aerosols. One of two primary chlorofluorocarbons that photolyze at high altitudes to release chlorine atoms. An important factor in ozone depletion. Also known as trichlorofluorocarbon.

CFC-12 (CF2Cl2) - Halocarbon compound used in air conditioning systems as a refrigerant. One of two primary chlorofluorocarbons that photolyze at high altitudes to release chlorine atoms. An important factor in ozone depletion. Also known as dichlorofluoromethane.Chapman Reactions - Stratospheric reactions in which ozone dissociates into molecular oxygen and atomic oxygen, and the resulting free oxygen atoms recombine with ozone to form molecular oxygen. The process was first described by a British physicist named Sydney Chapman in 1930.

Chappuis band - Ozone absorption band extending from 450 to 750 nm (very weak compared to other bands). See Hartley and Huggins bandsband

CGAM - Centre for Global Atmosphere Modelling

chlorine (Cl) - Heavy, greenish-yellow, irritating gas with a pungent odor. Capable of reacting with almost all other elements. Catalyst for ozone destruction.

chlorine monoxide (ClO) - Intermediate product of chlorine interaction with ozone.

chlorine nitrate (ClONO₂) - Compound formed by the reaction of ClO and NO₂. Slows the rate of ozone destruction, as it is much less reactive than ClO. May also react to produce HOCl, which is rapidly photolyzed into Cl and ClO, reactive chlorine and chlorine monoxide.

chlorofluorocarbons (CFC's) - Group of inert, nontoxic, nonflammable compounds made up of chlorine, fluorine, and carbon; used as a refrigerator coolant, foam insulation and cleaning agents as well as aerosol propellants. CFC's were thought of as a great replacement for ammonia because ammonia is very flammable. CFC's are safe, nonreactive (inert) molecules in the lower atmosphere (troposphere), but in the stratosphere, where the UV radiation is intense, CFC's are broken down. UV light breaks the bond between the carbon and chlorine on the CFC molecule. With the highly reactive chlorine atom, now free, it reacts with ozone and destroys it.

CITE - Chemical Instrumentation Test and Evaluation (CITE)

climatological ozone profiles - Twenty-three standard profiles derived from a combination of SBUV measurements taken at altitudes greater than 16-mbar and low altitude balloon radiosonde data. Yearly averages were developed for three latitude bands: low (15°), mid (45°), and high (75°).

climatological temperature profiles - Standard temperature profiles obtained from the Environmental Science Services Administration.

CLAES - Cryogenic Limb Array Etalon Spectrometer

CMDL - NOAA Climate Monitoring and Diagnostics Laboratory

CNES - Centre National d'Etudes Spatiales

CRISTA - CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere

CTM - Chemical Transport Model

D

DAAC - Distributed Active Archive Centre D

ARA - Deutsche Agentur fr RaumfahrtAngelegenheiten (Germany)

deoxyribonucleic acid (DNA) - Self replicating nucleic acid that contains genetic code within the cell. The primary structure consists of two long nucleotide chains that are joined by hydrogen bonds and twisted together to form a double helix.

descending node - The point at which an orbiting object or spacecraft, moving from north to south, crosses the plane of the equator.

DIAL - Differential Absorption Lidar. DIAL technique has been in use for ozone measurements since 1966.

dichlorofluoromethane (CF₂Cl₂) - Halocarbon compound used in air conditioning systems as a refrigerant. One of two primary chlorofluorocarbons that photolyze at high altitudes to release chlorine atoms. An important factor in ozone depletion.

DOAS - Differential Optical Absorption Spectrometers

Dobson Spectrophotometer - A ground-based instrument that measures the amount of ozone present in the atmosphere. The Dobson spectrophotometer was designed by British physicist Gordon Dobson in the 1927. The Dobson spectrophotometer measures UV light from the sun at two to three pairs of wavelengths in the Huggins band (310 to 350 nm). Each pair is given a letter deignation. There are the Apair(305.5 and 32.4 nm), the B pair (308.8 and 329.1nm), the C pair (311.45 and 332.4 nm), the D pair (317.6 and 339.8 nm) etc. each member of a pair is separated by approximatel 2025 cm-1.

Dobson Unit (DU) - The standard unit of measurement of total ozone equal to 2.69 x 10¹⁶ molecules per square centimeter. An equivalent amount of ozone, at 1 atmosphere and 273° K, would form a layer 0.001 cm thick. In otherwords if all of the ozone from the Earth's surface to outer space were compressed to standard temperature and pressure (STP), the ozone layer or its thickness would be about 3 mm thick. At STP, 3mm of ozone is 300 Dobson Units (DU). 1mm = 100DU.

E

EASOE - European Arctic Stratospheric Ozone Experiment

Ebert-Fastie monochromatic spectrometer - Instrument used to measure energy intensity within the ultraviolet region of the electromagnetic spectrum.

ECC - Electrochemical cell ozonesonde

ELDONET - European Light DOsimeter NETwork

ERBS - Earth radiation budget

ERBS - Earth radiation budget satellite

ENVISAT - Environmental Satellite

EOS - Earth Observing System

EP - Earth Probe

EPV - Ertel's Potential Vorticity

ER2 - European Remote Sensing-2 Satellite

ESE - NASA's Earth Science Enterprise

ESTEC - European Space Research and Technology Center

EUMETSAT - European Organisation for the Exploitation of Meteorological Satellites

EUV - Extreme ultraviolet

exosphere - Region of the atmosphere beyond 400 km. that fades into interplanetary space.

F

Fourier transform spectrometer (FTS) - Spectrometer that consists of a collimator and beamsplitter, which divides the source beam into two parallel beams with equal amplitudes.

G

GARP - Global Atmospheric Research Programme

GCM - Global Circulation Model

GDAS - Global Data Assimilation System

GEO - Geostationary Earth Observatory

GEOS - DAS Goddard Earth Observing System Data Assimilation System

GHIS - GOES High Resolution Interferometer Sounder

GLAS - Geoscience Laser Altimeter System

GLAS - Goddard Laboratory for Atmospheric Sciences

global warming - Rise in global temperature caused by increased amounts of atmospheric gases that trap heat in Earth's atmosphere by absorbing longwave radiation.

global warming potential (GWP) - A relative measure of the warming effect that the emission of a gas might have on the surface troposphere. It is measured as a factor relative to CO2

GLOSS - UKMO data analysis system

GLRS - Geoscience Laser Ranging System

GMS - Geostationary Meteorologicl Satellite

GOES - Geostationary Operational Environmental Satellite

GOME - Global Ozone Monitoring Experiment

GOMOS - Global Ozone Monitoring by Occultation of Stars

GO₃OS - Global ozone observing system

GOSCOMP -Global Operational Sea Surface Temperature Computation

GPS - Global Positioning System

GRACE - Gravity Recovery and Climate Experiment GUV Ground-based Ultraviolet Radiometer

GRAS - GNSS Receiver for Atmospheric Sounding

GRIB - Grid data in binary form

greenhouse effect - Heating effect exerted by the atmosphere upon the earth because the atmosphere absorbs and reemits infrared radiation.

greenhouse gas - A gas that absorbs infrared radiation and in turn emits it in the atmosphere. The net effect is a local trapping of energy and a tendency to warm the earth's surface. Water vapour (H2O), carbon dioxide (CO2) methane (CH4), nitrous oxide (N2O) and ozone (O3) are the primary greenhouse gases in the Earth's atmosphere.

ground-level Ozone (bad ozone) - Ozone that is at the surface of the Earth, and is a major component of smog. Ground-level ozone is formed when nitrogen oxides from the burning of fossil fuels, react in sunlight and stagnant air, with volatile organic compounds (VOC) that come from the fumes of fuels, solvents and other human-produced sources. Ground- level ozone is harmful, whereas stratospheric ozone is beneficial.

ground-truth data - Field observations that are used to check the accuracy of satellite measurements.

GSFC - Goddard Space Flight Center

GSM - Global Spectral Model

GTE - NASA Global Tropospheric Experiment

GTS - Global Telecommunications System

GVAR - GOES Variable

GWP - Global Warming Potential

H

HALOE Halogen Occultation Experiment

halon - Compound formed when a halogen, such as fluorine (F) or bromine (Br) attaches to a carbon atom.

Hartley band - Ozone absorption band extending from 200 to 310 nm (peaks near 255 nm) in a bell shape. (see Huggins & Chappuis bands)

HCFC - Hydrochlorofluorocarbon

HFC - Hydrofluorocarbon

HIRDLS - High Resolution Dynamics Limb Sounder

HIRIS - High Resolution Imaging Spectrometer

HIRS High Resolution Infrared Radiation Sounder

HIS - High Spectral Resolution Interferometer Sounder

HMMR - High Resolution Multifrequency Microwave Radiometer

HRDI - High Resolution Doppler Interferometer

HRIR - High Resolution Infrared Radiometer

HRIS - High Resolution Imaging Spectrometer

HSCT - High-Resolution Civil Transport

Huggins band - Ozone absortion band extending from 310 to 350 nm, weaker than Hartley band (see Hartley and Chappuis bands)

hydrogen - A highly flammable, colorless gaseous element, the most abundant element in the universe and the lightest of all gases.

hydrogen chloride (HCl) - Important chlorine-containing compound formed from the breakdown of chlorofluorocarbons. Also produced by volcanic eruptions. Less reactive than chlorine.

hydrogen fluoride (HF) - Important fluorine-containing compound formed from the breakdown of chlorofluorocarbons. Also a product of volcanic eruption.

I

IASB - Institut d'Aeronomie Spatial de Belgique

IASI - Infrared Atmospheric Sounding Interferometer

IFOV - Instantaneous Field of View

IFS - Integrated Forecasting System (ECMWF's forecasting model)

instantaneous field of view (IFOV) - Ground or target area viewed by a sensor at a given point in time.

IGAC - International Global Atmospheric Chemistry

IGBP - International Geosphere-Biosphere Program

IGY - International Geophysical Year

ILAS - Improved Limb Atmospheric Spectrometer

IMG - Interferometric Monitor for Greenhouse Gases

IMK - Institut fuer Meteorologie und Klimaforschung

infrared radiation - Electromagnetic radiation having a wavelength slightly longer than visible red light, from 750 nanometers to 1 millimeter.

infrared radiometer - Sensor that measures the intensity of infrared radiation (720 nm-1500 nm) within a specific field of view.

INTERDOL - INTERcomparison of envisat chemistry instruments data to strengthen the global monitoring of the Depletion of the Ozone Layer

INTEX-A - Intercontinental Chemical Transport Experiment, North America

IOC - International Ozone Commission

IPCC - Intergovernmental Panel on Climate Change

IR - Infrared

IRIS - Infrared Interferometer Spectrometer Radiometer

irradiance - Radiant flux per unit area of a surface.

IRTS - Infrared Temperature Sounder

ISAMS - Improved Stratospheric and Mesospheric Sounder

ISS - International Space Station

ITCT - Intercontinental Transport and Chemical Transformation

ITCZ - Intertropical Convergence Zone

ITIR - Intermediate Thermal Infrared Radiometer

ITOP - Intercontinental Transport of Pollution

ITOS - Improved TIROS Operational System

ITPR - Infrared Temperature Profile Radiometer

IUP - Bremen Institute of Environmental Physics, University of Bremen

J

JEM/SMILES - Superconducting Sub-Millimeter Wave Limb Emission Sounder on the Japanese Experimental Module of the International Space Station

JGR - Journal Of Geophysical Research

JMA - Japan Meteorological Agency

JPL - Jet Propulsion Laboratory

K

ketones - Organic compounds in which the carbon atoms of two hydrocarbon radicals are linked to a carbonyl group. Generally represented by the formula R(CO)R1, where R1 and R may be the same.

KF - Kalman Filter

KNMI - Het Koninklijk Nederlands Meteorologisch Instituut

L

Langrangian point - In a system dominated by two attracting bodies (such as Sun and Earth), a point at which a third, much smaller body (such as a satellite) keeps the same position relative to the other two. Theoretically, the Sun-Earth system has 5 Lagrangian points, but only two are important: L1, on the sunward side of Earth, about 4 times the distance of the Moon, and L2 at approximately the same distance on the midnight side.

LASA - Lidar Atmospheric Sounder and Altimeter

Laser - Light Amplification by the Stimulated Emission of Radiation. A device for producing a coherent monochromatic high-intensity beam of light.

LAWS - Laser Atmospheric and Wind Sounder

LEO - Low Earth Orbit

LIDAR (light detection and ranging) - A technique for active remote sensing in which a light source is used to probe the atmosphere. Laser light fired at the atmosphere is reflected back by the atmospheric molecules to a detector and the attenuation (reduction) of this light provides information on atmospheric particles and molecules. Changes in the returned wavelengths can provide information about atmospheric motion. The primary advantage of this technique is its ability to obtain high vertical resolution data at different altitudes. This is important for studying how various trace gases (see Chapter 2) are transported by the wind. Lidar is also used to measure the cloud altitude. This information is important for pilots and for meteorological observations.

limb emission technique - Also called limb sounding technique. Instruments based upon the limb emission technique infer trace gas amounts (such as ozone) from measurements of longwave radiation (infrared or microwave) thermally emitted in the atmosphere along the line of sight of the instrument. The altitude to which the instrument can see is called the tangent altitude. In theory, the instrument could look all the way to the surface, but below a certain altitude (under 10 km), clouds interfere with the emitted longwave radiation. This radiation emission occurs along the geometric path between the tangent altitude and the satellite instrument. This horizontal path is quite long compared to the tangent altitude.

LIMS - Limb Infrared Monitor of the Stratosphere

lithosphere - Solid mass of Earth composed of rock, soil, and sediment.

LIS - Lightning Imaging Sensor

LLR - Laser Retro Reflector

LMD - Laboratoire de Meteorologie Dynamique, Paris

LOS - Line Of Sight

LRIR - Limb Radiance Inversion Radiometer

LUT - Look Up Table

LW - Long wave

Lyman-alpha emission band - The radiation emitted by hydrogen at 1216 Angstrom, first observed in the solar spectrum by rocketborne spectrographs. Lyman-alpha radiation is very important in the heating of the upper atmosphere, thus it affects other atmospheric phenomena. Also called Lyman-alpha radiation.

M

MAERI - Marine Atmosphere Emitted Radiance Interferometer

MAESA - Measurements for Assessing the Effects of Stratospheric Aircraft

MAESTRO - Measurements of Aerosol Extinction in the Stratospheric and Troposphere Retrieved by Occultation (flown on SCISAT)

MAHRSI - Middle Atmosphere High Resolution Spectrograph Investigation

MAPS - Measurement of Air Pollution from Satellites

MAPSCORE - Mapping of Polar Stratospheric Clouds and Ozone Levels Relevant to the Region of Europe

MARS - Meteorolical Archive and Retrieval System (ECMWF)

MAS - Microwave Atmospheric Sounder

MASGRAS - data from combination of a passive microwave MAS, and a radio occultation instrument GRAS mounted on the International Space Station NSS Receiver for Atmospheric Sounding

MASP - NCAR Multiangle Aerosol Spectrometer Probe

MASTER - Millimeter Wave Acquisitions for Stratosphere/Troposphere Exchange Research

Maunder minimum - The period from 1654 to 1714 when it was believed that there were no sunspots. It is now thought that there were some sunspots during that time but fewer than those counted after 1800. Sunspots occur in 11-year periods. They also occur in a 90-year cycle called the Gleissberg cycle. The Maunder minimum may form part of an as-yet-unknown larger cycle of sunspot activity whose periodicity is longer than the historical record.

MCSST - Multichannel Sea Surface Temperatures

Mercury-Argon calibration lamp - Lamp that produces radiation centered at 253.7 nm, which is then diffused from a diffuser plate. Radiation measurements are made at multiple wavelengths and possible shifts are noted.

MERIS - Medium Resolution Imaging Spectrometer

mesopause - Transitional atmospheric region between the mesosphere and thermosphere.

mesosphere - Region of the atmosphere, between approximately 50 to 100 km, in which temperature decreases with altitude.

METAR - Meteorological Airfield Report

METDB - METeorological Data Base (Met Office)

Meteor-3 - Third in a series of weather satellites launched by the former Soviet Union. Launched in August 1991 with a payload that included a Total Ozone Mapping Spectrometer (TOMS).

METEOSAT - Meteorological Satellite

methane - Simple combustible hydrocarbon. The major component of natural gas.

METOP - Meteorological Operation Program (planned polar orbiter satellites)

METSAT - Meteorological Satellite

MHS - Microwave Humidity Sensor

microwave radiometer - Sensor that measures the intensity of microwave radiation (0.3 cm-30 cm) within a specific field of view.

Mie scattering - Atmospheric scattering caused by large particles such as dust, pollen, smoke, and water droplets. More prevalent in the lower atmosphere, from 0 to 5 km.

MIMR - Multifrequency Imaging Microwave Radiometer

MIPAS - Michelson Interferometer for Passive Atmospheric Sounding

MiroTops - A hand held spectrophotometer that measures the amount of ozone in the stratosphere. By lining up the Sun in its window, the UV intensity is measured at 3 wavelengths between 305.5 and 320 nm.

MISR - Multiangle Imaging Spectro Radiometer

mixing ratio - Relative number of molecules of a specific type in a given volume of air.

monochromator - Spectrometer that operates within a narrow range of the electromagnetic spectrum.

Montreal protocol - The Montreal protocol is an international agreement, under the United Nations Environmental Programme (UNEP), which implements controls on the consumption of ozone-depleting substances. The Protocol was signed on September 16, 1987 and originally negotiated between 24 countries. The Protocol is amended from time to time. To date, over 175 countries have signed the Protocol.

MLS - Microwave Limb Sounder

MMCC - Mission Management Control Centre

MO - The Met Office (UK)

MODIS - Moderate Resolution Imaging Spectrometer

MOPITT - Measurements of Pollution in the Troposphere

MOPS - Moisture Observation Pre-processing System

MORECS - Met Office Rainfall and Evaporation Calculation System

MOSES - Met Office Surface Exchange Scheme

MOZART - a Model for OZone and chemical tracers

MRF -Medium Range Forecast

MRIR - Medium Resolution Infrared Radiometer

MSC - Meteorological Satellite Centre

MSDOL - Monitoring of Stratospheric Depletion of Ozone Layer

MSG - Meteosat Second Generation

MSSCC - Multicolour Spin Scan Cloud Camera

MSU - Microwave Sounding Unit

MTPE - Mission To Planet Earth

MTS - Microwave Temperature Sounder

MUSE - Monitor of Ultraviolet Solar Energy

MWR - Microwave Radiometer

N

NACP - North American Carbon Program

nadir - The direction from a spacecraft directly down toward the center of a planet. Opposite is the satellite zenith.

NAP - National Action Plan for the Environmental Control of Ozone-Depleting Substances and their Halocarbon Alternatives

NASA - National Aeronautics and Space Administration

NASDA - National Space Development Agency

NCAR - National Centre for Atmospheric Research (USA)

NCDC - National Climatic Data Centre

NCEP - National Centers for Environmental Prediction (USA)

NDSC - Network for the Detection of Stratospheric Change

NERC - Natural Environment Research Council (UK)

NESDIS - National Environmental Satellite, Data and Information Service

NESR - Noise Equivalent Spectral Radiance

NGDC - National Geophysical Data Center

NILU - Norwegian Institute for Air Research

NIR - Near Infrared

nitrogen - A colorless, odorless, nonmetallic element that occurs as a diatomic gas and constitutes nearly 80% of the atmosphere by volume.

nitrous oxide (N₂O) - Colorless gas, naturally produced through bacteriological decomposition of organic matter. Also produced anthropogenically and used as a mild anesthetic.

NMC - National Meteorological Centre (USA)

NOAA - National Oceanic and Atmosphere Admisistration

noctilucent clouds - 1. Relatively unusual wavy, thin, bluish-white clouds that form at altitudes of about 80 to 90 km. 2. Clouds of unknown composition that occur at great heights, 75 to 90 km. They resemble thin cirrus, but usually with a bluish or silverish color, although sometimes orange to red, standing out against a dark night sky. Sometimes called luminous clouds. These clouds have been seen rarely, and then only during twilight, especially with the Sun between 5 and 13 below the horizon. They have been observed only during summer months in both hemispheres (between latitudes 50 to 75 N and 40 to 60 S), and only in some parts of these latitude belts.

NOZE - National Ozone Expedition

NPOESS - The National Polar-orbiting Operational Environmental Satellite System

NRL - Naval Research Laboratory

NRT - Near Real Time

NSBF - National Scientific Balloon Facility

NSSDC - National Space Science Data Centre

NTP - Normal temperature and Pressure

NWP - Numerical Weather Prediction

O

occultation technique - One of several remote sensing techniques for measuring atmospheric trace gases by satellite. Occultation instruments measure solar, lunar, and even stellar radiation directly though the limb of the atmosphere during satellite Sun, Moon, and star rise and set events (depending on which celestial radiator is being used by the satellite instrument). By measuring the amount of absorption of radiation through the atmosphere at different wavelengths (e.g., UV, visible, infrared), occultation instruments can infer the vertical profiles of various trace constituents, including ozone. This technique offers improved vertical resolution with solar occultation instruments offering vertical resolutions of 1-2 km. Disadvantage is the limited spatial coverage: measurements can only be made at sunrise and sunset events for the solar occultation instruments, so many orbits are required in order to get global coverage. The solar occultation technique refers to instruments that use only solar radiation for the occultation technique. Improved designs of occultation instruments allow for use of the Moon and even the stars as the occulting light sources, which will expand the spatial coverage. SAGE is an example of an instrument employing an occultation technique.

ODP - Ozone Depleting Potential. A measure of the capability of a particular chemical to destroy ozone, measured against CFC-11 which has an ozone- depleting potential of 1. For ODP values of ozone-depleting substances

ODS - Ozone Depleting Substance. A chemical compound that contributes to stratospheric ozone depletion. ODS are stable in the troposphere and only degrade under intense ultraviolet light in the stratosphere.

ODS -react with stratospheric ozone, either directly or through the release of chlorine or bromine atoms after decomposition.

ODSR - Ozone-Depleting Substances Regulations, 1998

OGO - Orbiting Geophysical Observatory. OGO 1V carried UV airglow spectrometer to make measurements of UV airglow in the 100-340 nm region. Global ozone was measured (1967 to 1968) by observing back scattered solar radiation in the 255-301 nm region while looking in the nadie direction.

OMI - EOS-Aura Ozone Monitoring Instrument (to be launched 2004)

OMS - Observation of the Middle Stratosphere

OMPS - Ozone Mapping and Profiler Suite

OPD - Observation Processing Database

OPS - Observation Processing System (data selection and quality control system) of the Met Office

optical spectrum - Portion of the electromagnetic spectrum, from 0.30 to 15 micrometers, that can be reflected and refracted with mirrors and lenses.

OSIRIS - Optical Spectrograph and InfraRed Imager System (Canadian instrument)flown on Odin satellite, measures ozone absorption limb spectra in the ranges 300-340 and 400-700 nm.

OVID - Optical Visible and near Infrared Detector

oxygen - A nonmetallic element that occurs as a diatomic gas and constitutes 21% of air by volume, essential for plant and animal respiration, and required for almost all combustion.

ozone (O₃) - A gaseous form of oxygen with three atoms per molecule. Ozone is a bluish gas that is harmful to breathe. Nearly 90% of the Earth's ozone is in the stratosphere and is referred to as the ozone layer. Ozone absorbs a band of ultraviolet radiation called UVB that is particularly harmful to living organisms. The ozone layer prevents most UVB from reaching the ground.

ozone depletion - The thinning of the earth's protective stratospheric ozone layer. Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is tipped in favour of destruction. Human activity is the major factor in tipping that natural balance, mostly from artificial chemicals, known as ozone- depleting substances (ODS).

ozone hole - Region of rapid, dramatic ozone depletion over Anarctica during the polar spring. It is confined to south of 55° latitude and disperses soon after temperatures rise above -80° C. Though the ozone hole started in the Antarctic since mid 1970s, it was discovered by Dr. Joe Farman of the British Antarctic Survey team in 1985.

ozone layer - Most of the ozone in the atmosphere is in the stratosphere (about 10 - 50 km above earth's surface). This is what is called the ozone layer or the stratospheric ozone layer. The layer refers to the thickness of the ozone.

OZVAL - Geophysical cross-VALidation of Envisat OZone products through assimilation in a global photochemical transport model (an ENVISAT AO proposal)

P

PBL - Planetary Boundary Layer

PDF - Probability Density Function

PEM - GTE Pacific Exploratory Missions

perihelion - That point in a solar orbit nearest the Sun. That orbital point farthest from the Sun is called aphelion. The term perihelion should not be confused with parhelion, a form of halo

PF - Perturbation Forecast

PHOBEA - Photochemical Ozone Budget of the Eastern North Pacific Atmosphere

peroxyacyl nitrates (PAN) - Damaging photochemical oxidants that are very irritating to the eyes and throat. Represented as R(CO)OO(NO₂) where R denotes a hydrocarbon ring or chain.

photochemical - Of or relating to the effect of radiant energy on a chemical system.

photolysis - Dissociation process driven by the Sun's radiation.

photosynthesis - Chemical process driven by solar energy in which CO₂ and H₂O, in the presence of chlorophyll, are converted to oxygen and carbohydrates. Oxygen and water vapor are released in the process.

PMD - Polarisation Measurement Device

PMR - Pressure Modulator Radiometer

PMSL - Pressure Mean Sea Level

POAM - Polar Ozone Aerosol Measurement

POD - Precise Orbit Determination

POEM - Polar Orbit Earth Observation Missions

POES - Polar Orbiting Operational Environmental Satellite

POLARIS - Photochemistry of Ozone Loss in the Arctic Region in Summer

polarization - Uniform and nonrandom elliptical, circular, or linear variation of a wave, characteristic in light or other radiation.

polar stratospheric clouds (PSC) - High, thin clouds composed of nitric acid and water that form in the coldest regions of the stratosphere when temperatures drop below -80°C. Ice crystal surfaces within these clouds are efficient in converting inert chlorine reservoirs, such as ClONO₂ and HCl, into reactive chlorine compounds.When exposed to Sun in late August, UV radiation triggers reactions with chlorine and bromine that destroy ozone. The result is an ozone hole. A similar, but not as extensive destruction of ozone takes place in the Arctic under the same conditions, but the temperatures do not get as cold, therefore fewer PSCs form

polar vortex - Wind region around the North or South pole. The southern vortex is a well formed circular to oblong mass of extremely cold, stagnant air, held in place by the ocean surrounding the Antarctic land mass and a strong westerly circulation pattern produced by the coriolis effect. The northern vortex is not as distinct because the Arctic is a frozen ocean surrounded by rugged land masses, which cause the circulating winds to encounter a variety of temperatures.

PPMV - Parts Per Million by Volume

PRT - Photochemical Replacement Time

PSAS - Physical space Statistical Assimilation System

PSC - Polar Stratospheric Cloud

PV - Potential Vorticity

Q

quasi-biennial oscillation (QBO) - Periodic variation in the direction, either easterly or westerly, of tropical lower stratospheric winds. The direction changes every 26 months.

QUILT - Quantification and Interpretation of Long-Term UV-Vis Observations of the Stratosphere

R

RA-2 Radar Altimeter 2

radiosonde - Balloon borne instrument used to measure and transmit meteorological data.

RAL - Rutherford Appleton Laboratory (UK)

Rayleigh scattering - Dominant form of light scattering in the upper atmosphere, which produces the blue color of the sky. It is caused by atmospheric particulates that have very small diameters relative to the wavelength of the light, such as atmospheric gases like nitrogen and oxygen. Rayleigh Scattering attenuates the radiation with a spectral dependence varying as the inverse fourth power of the wavelength, making it important at UV bands.

reflective spectrum - Portion of the optical spectrum, from approximately 0.38 to 15 micrometers, that defines the direct solar radiation used in remote sensing.

reflectivity - Ratio of intensity of the total radiation reflected from a surface to the total radiation incident on the surface.

residual - The vector difference y-H[x], where y is the observation vector, H is the forward model, and x is the analysis.

RFTOZ - Regional dIFferences in Transformation of Ozone

RFTOZAL - Regional dIFferences in Transformation of Ozone and AerosoL

RIS - Retrofreflector in Space

RMS - Royal Meteorological Society (UK)

RMS - Root Mean Square

ROCOZ-A - - Rocket ozonesonde-A

ROSE - Research on Ozone in the Stratosphere and its Evolution

RTM - Radiative Transfer Model

RTTOV - Radiative Transfer Model for TOVS

S

SABER - Sounding of the Atmosphere using Broadband Emission Radiometry

SAGE - Stratospheric Aerosol and Gas Experiment

SAMS - Stratospheric and Mesospheric Sounder

SA/CNRS - Service d'Aeronomie/ Centre National de la Recherche Scientifique (France)

SAFARI - Southern African Regional Science Initiative

SAFIRE - Spectroscopy of the Atmosphere Far Infrared Emission SAR Synthetic Aperture Radar

SAGE - Stratosphere Aerosol and Gas Experiment

SAM - Satratospheric Aerosol Measurement

SAMMOA - Spring-to-Autumn Measurements and Modelling of Ozone and Active Species

SAMS - Satratospheric and Mesopheric Sounder

SAO - Semi-Annual Oscillation.

satellite zenith angle - Angle between the position of a satellite and the zenith, which is the point directly over the observed target.

SATOBS - Geostationary Satellite Data (Met Office data analysis system)

SBUV - Solar Backscatter Ultraviolet Instrument

SBUV/2 - Solar Backscatter Ultraviolet-2 Instrument

SCAMS - Scanning Microwave Spectrometer

SCANSAR - Scanning SAR Imaging Technique (for wide swath coverage)

SCATS - Scatterometer Winds (Met Office data analysis system)

SCIAMACHY - Scanning, Imaging Absorption Spectrometer for Atmospheric Cartography

SCISAT-1 - canadian satellite (Atmospheric chemistry experiment)

SCMR - Surface Composition Mapping Radiometer

SCR - Selective Chopper Radiometer

SCS - Suite Control System (Met Office)

SEAWIFS - Sea Wide Field-of-view Spectrometer

SEM - Space Environment Minister

semi-annual oscillation (SAO) - The oscillation in upper level stratospheric winds over the tropics between easterly and westerly directions roughly every 6 months. It is due to the passage of the Sun over the equator twice a year.

SEVIRI - Spinning Enhanced Visible and Infrared Imager (on MSG-1 satellite)

SHADOZ - Southern Hemisphere Additional Ozonesondes

ShAGME - Shared Assimilation for Geophysics Meteorology and the Environment (provisional)

SIRIS - Stratospheric Infrared Interferometer Spectrometer

SIRS - Satellite Infrared Spectrometer

SLIMCAT - Single layer Isentropic Model of Chemistry And Transport

SLR - Satellite Laser Ranging

SME - Solar Mesospheric Explorer carried limb scanning ultraviolet spectrometer (200 to 340 nm spectral region) and near-IR spectrometer (1.27 micron) to measure ozone densities in the lower mesosphere.

SMM - Solar Maximum Mission

SMMR - Scanning Multichannel Microwave Radiometer

SMR - Sub-Millimeter Radiometer (flown on satellite Odin), measures an ozone spectral line at 501.4 GHz.

SMS - Synchronous Meteorological Satellite

SOCC - Satellite Operations Control Centre

SODA - Studies of Ozone Distribution based on Assimilated satellite measurements

SOI - Spin scan ozone imager

solar cycle - Periodic change in sunspot activity. One cycle is approximately 11.1 years.

solar zenith angle - Angle between the position of the Sun and the zenith, which is the point directly over an observed target.

SOLSE - Shuttle Ozone Limb Sounding Experiment

SOLSTICE - Solar Stellar Irradiance Comparison Experiment

SOLVE - SAGE III Ozone Loss and Validation Experiment (SOLVE)

SONDES - radiosondes and wind profilers (Met Office data analysis system)

SONEX - SASS Ozone and NOx Experiment

SONTOS - Southern Ontario Oxidant Study

SOPRANO - Sub-Millimeter Observation of Processes in the Atmosphere noteworthy for Ozone

SOS - Southern Oxidants Study

SPADE - Stratospheric Photochemistry, Aerosols and Dynamics Expedition

SPARC - Stratospheric Processes And their Role in Climate

spectrometer - Instrument used to determine the distribution of energy within a spectrum of wavelengths.

SPOT - Systeme Probatoire d'Observation de la Terre

SR - Scanning Radiometer

SSBUV - Shuttle Solar Backscatter Ultraviolet Instrument

SSI - Spectral Statistical Interpolation

SSM/I - Special Sensor Microwave Imager

SSM/T - Special Sensor Microwave Temperature

SSST - Skin Sea Surface Temperature

SST - Sea Surface Temperature

SSU - Stratospheric Sounding Unit

STE - Stratospheric-Tropospheric Exchange

STEP - Stratospheric-Troposphere Exchange Project

STP - Standard Temperature and Pressure

STRAT - Stratospheric Tracers of Atmospheric Transport

stratopause - Transition layer between the stratosphere and mesosphere. Marks the maximum altitudinal temperature increase within the stratosphere.

stratosphere - Portion of the atmosphere between the tropopause, at approximately 8 to 15 km, and 50 km in altitude, depending upon latitude, season, and weather.

STROZ-LITE - Stratospheric Ozone Lidar Trailer Experiment, a mobile lidar system for measuring vertical profiles of atmospheric ozone, aerosol particles, and temperature.

sulfur dioxide (SO₂) - Chemical compound that absorbs radiation of the same wavelength absorbed by ozone. Product of large volcanic eruptions.

sulfuric acid (H₂SO₄) - Heavy, corrosive, oily acid. Vigorous oxidizing agent. Ozone concentrations may be affected by reactions on the surface of sulfuric acid clouds, resulting from major volcanic eruptions.

sunspot - Relatively dark, sharply defined region on the Sun associated with an intense magnetic field.

SUSIM - Solar Ultraviolet Spectral Irradiance Monitor

SUVDAMA -Scientific UV DAta MAnagement (European project)

SW - Shortwave

SYNOPS - surface synoptic reports (Met Office data analysis system)

T

TES - Tropospheric Emission Spectrometer (onboard EOS-Aura, to be launched in 2004)

thermopause - Transition layer between the thermosphere and exosphere, located at approximately 600km in altitude.

thermosphere - Region of the atmosphere in which temperature increases with altitude. Located at approximately 100 to 400 km.

THIR - Temperature Humidity Infrared Radiometer

TIP - TIROS Information Processor

TIROS - Television and Infrared Observational Satellite

TMI - TRMM Microwave Imager

TMR - TOPEX Microwave Radiometer

TOA - Top Of Atmosphere

TOMS - Total Ozone Mapping Spectrometer(measures between 312- 360 nm)

TOMS3F - Total Ozone Measurements by 3 platforms(Satellites, Sondes, and Spectrometers) at Fairbanks

TOPSE - Tropospheric Ozone Production about the Spring Equinox

TOTE/VOTE - Tropical Ozone Transport Experiment/Vortex Ozone Transport Experiment

TOTTIE - Total Ozone Tropospheric Trends In the Environment (provisional)

TOVS - TIROS Operational Vertical Sounder

TRACE-P - TRAnsport and Chemical Evolution over the Pacific

trichlorofluorocarbon (CFCl₃) - Halocarbon compound used in aerosols. One of two primary chlorofluorocarbons that photolyze at high altitudes to release chlorine atoms. An important factor in ozone depletion.tropopause - Boundary between the troposphere and stratosphere, from 8 km in the polar regions to 15 km in the tropics. Marks the vertical limit of most weather phenomena.

troposphere - Lowest region of the atmosphere, defined by a steady decrease in temperature with altitude. Extends to approximately 15 km above Earth's surface.

tropospheric - Having to do with the lowest region of the atmosphere, which extends to approximately 15 km above Earth's surface.

TWERLE - Tropical Wind Energy Conversion and Reference Level Experiment

U

UARP - Upper Atmosphere Research Program

UARS - Upper Atmosphere Research Satellite

UGAMP - Universities Global Atmospheric Modelling Programme (UK)

UHF - Ultra High Frequency

UKMO - United Kingdon Meteorological Office (acronym now obsolete)

UM - Unified Model (Met Office)

Umkehr Technique - The Umkehr method is ground based optical remote sensing. Observations are made on the clear zenith sky as the Sun is rising or setting. Umkehr retrieved ozone profile covers a range up to 40 km which is not reached by operational balloon sonde. The Umkehr profile is normally given in 10 layers.

UNEP - United Nations Environmental Program

UPMC - University of Pierre and Marie Curie, Paris, France

USGCRP - US GLobal Change Research Programme z

UTC - Coordinated Universal Time

UTLS - Upper Troposphere Lower Stratosphere

UV - Ultra Violet light, wavelength region of the solar spectrum from approximately 200 to 380 nm

UV-A - Unharmful ultraviolet light from the Sun with a wavelength between 320-400 nm. UV-A light is not absorbed by ozone, thus all of the UV-A light is allowed to reach the surface of the Earth.

UV-B - ultraviolet light from the Sun with a wavelength between 290-320 nm. Ozone absorbs most UV-B light before it reaches the surface of the Earth, harmful to living organism.

UV-C - high energy ultraviolet light from the Sun with a wavelength between 200-290 nm. Ozone and oxygen molecules absorb all UV-C light before it can reach the Earth's surface.

UV Index - a measure of the level of solar UV radiation at the Earth's surface

UARS - Upper Atmosphere Research Satellite. NASA satellite launched in September 1991. Platform for instruments to measure temperature, wind, and composition of the upper atmosphere, including the stratosphere.

V

Var - Variational Data Assimilation

VAROBS - OBServations file used in the Variational Data Assimilation Scheme (Met Office)

VAS - VISSR Atmospheric Sounder

VDUC - VAS Data Utilization Centre

VHRR - Very High Resolution Radiometer

VIRR - Visible and Infrared Radiometer

VIRS - Visible Infrared Scanner

VIRSR - Visible Infrared Scanning Radiometer

VIS - Visible region of solar spectrum

VISSR - Visible and Infrared Spin Scan Radiometer

VMR - Volume Mixing Ratio

VTPR - Vertical Temperature Profile Radiometer

W

WAS - Whole Air Sampler (flown on ER-2)

WEFAX - Weather Facsilile

WMO - World Meteorological Organization

WOUDC - World Ozone and Ultraviolet Radiation Data Centre, managed by the Meteorological Service of Canada

WO - Harvard Water Ozone EXperiment (flown on ER-2)

WSR - Weather Service Radar

X

Y

Z