Glossary

AATSR
:Advanced Along-Track Scanning Radiometer 

Infrared imaging instrument onboard Envisat, used to study sea-surface temperatures. Follow-on from ATSR-1 and ATSR-2 on board ERS-1 and ERS-2. Data are derived from measurements of reflected and emitted radiation taken at several wavelengths.


ACC
:Antarctic Circumpolar Current 

Cold current encircling the Antarctic, driven by westerly winds between 40° and 50° South. The flow of the ACC is not checked by the continents. It thus links the Atlantic, Indian and Pacific Oceans.

 


Acclaim
:Antarctic Circumpolar Current Levels by Altimetry and Island Measurements 

ACW
:Antarctic Circumpolar Wave 

ADCP
:Acoustic Doppler Current Profiler 

ADT
:Absolute Dynamic Topography 

Sea surface height with respect to the geoid. Absolute dynamic topography is the sum of the Mean Dynamic Topography and of the Sea Level Anomalies. ADT = MDT+SLA = SSH - geoid

 


AGC
:Automatic Gain Control 

AGU
:American Geophysical Union 

AGU is a scientific society that aims to advance the understanding of Earth and space. AGU conducts meetings and conferences, publishes journals, books and a weekly newspaper, and sponsors a variety of educational and public information programs.

 


along-track
:

Along-track data are data chronologically ordered, following the satellite "ground track", i.e. the virtual track left by the radar beam on the ground.

 


Amma
:African Monsoon Multidisciplinary Analyses 

Amma is an international multidisciplinary program which was initiated to gain better understanding of the reasons beahind disturbances to the African monsoon.

 


AMSR-E
:Advanced Microwave Scanning Radiometer - Earth Observing System 

The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is a twelve-channel, six-frequency, passive-microwave radiometer system. It measures horizontally and vertically polarized brightness temperatures at 6.9 GHz, 10.7 GHz, 18.7 GHz, 23.8 GHz, 36.5 GHz, and 89.0 GHz. Spatial resolution of the individual measurements varies from 5.4 km at 89 GHz to 56 km at 6.9 GHz.

AMSR-E is an instrument onboard Aqua Satellite (Nasa)

 


AO
:Announcement of Opportunity 

Argo
:global array of temperature/salinity profiling floats 

Argo is a global array of 3,000 free-drifting profiling floats that measures the temperature and salinity of the upper 2000 m of the ocean.  This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection.

 


Arpege
:Action de Recherche Petite Echelle Grande Echelle 

Forecasting model used by the French weather service Météo-France.

 


Ascii
:American Standard Code for Information Interchange 

Ascii data are data stored in a text format (wrt binary data, which need to be read by binary/hexadecimal editors, or specific programs).
 Ascii data are somehow easier to read without background software, but give much heavier files than binary.

 


AVHRR
:Advanced Very High Resolution Radiometer 

Instrument flown on Noaa satellites that measures sea-surface temperatures. The AVHRR instrument operates in the infrared waveband.

 


Aviso
:Archiving, Validation and Interpretation of Satellite Oceanographic data 

Aviso distributes satellite altimetry data from Topex/Poseidon, Jason-1, ERS-1 and ERS-2, and EnviSat, and Doris precise orbit determination and positioning products.

 


AWI
:Alfred Wegener Institute 

bathymetry
:Measurement of the ocean depths 

biosphere
:The virtual layer made up by all living organisms on Earth 

BPR
:Bottom Pressure Recorders 

Calval
:CALibration - VALidation 

CCAR
:Colorado Center for Astrodynamics Research 

CCDP
:Centre de Controle Doris/Poseidon 

Doris/Poseidon control center

 


CCI
:Centre de Controle des Instruments 

Instruments control center

 


Cedre
:Centre de Documentation de Recherche et d'Expérimentations sur les pollutions accidentelles des eaux 

French research center on black tides and water pollution.


Ceos
:Committee on Earth Observation Satellites 

Cerfacs
:Centre Europeen de Recherche et de Formation Avancee en Calcul Scientifique 

European Center for Research and Advanced Training in Scientific Computation

 


Cersat
:Center for Satellite Exploitation and Research 

The Center for Satellite Exploitation and Research (CERSAT) is one of the major world data centers for oceanography. It processes, archives and distributes a large amount of data products obtained from satellite remote-sensing, mostly intended to support research activity in various fields (oceanography, meteorology, climatology,...) and operational applications based on space data.


CF COARDS
:Climate and Forecast - Cooperative Ocean/Atmosphere Research Data Service 

The COARDS format is a convention for the standardization of NetCDF (data format) files.

It is sponsored by the "Cooperative Ocean/Atmosphere Research Data Service ", a NOAA/university cooperative for the sharing and distribution of global atmospheric and oceanographic research data sets.

The CF (Climate and Forecast) conventions generalize and extend the COARDS conventions. The extensions include metadata that provides a precise definition of each variable. This standard also relaxes the COARDS constraints on dimension order and specifies methods for reducing the size of datasets.


Champ
:CHAllenging Minisatellite Payload 

gravimetric satellite (GFZ/DLR)

 


Clivar
:Climate Variability and Predictability 

WCRP program

 


CLS
:Collecte Localisation Satellites 

Founded in 1986, CLS is a subsidiary of Cnes and Ifremer, specialized in satellite-based data collection, location and ocean observations by satellite.

 


CMA
:Centre Multimissions Altimétrique 

altimetric multi-mission center. Processing center for altimetry missions (Jason-1, Envisat...)

 


Cnes
:Centre National d'Etudes Spatiales 

The Centre National d'Etudes Spatiales is a French industrial and commercial institution founded in 1961, in charge of the French space policy.

 


CNRS
:Centre National de la Recherche Scientifique 

The Centre National de la Recherche Scientifique (CNRS) is the leading research organization in France covering all the scientific, technological and societal fields.


Co-I
:Co-Investigator 

Member of a research group that is part of a science team (e.g. Ocean Surface Topography Science Team)


Coaps
:Center for Ocean Atmospheric Prediction Studies 

COARDS CF
:Cooperative Ocean/Atmosphere Research Data Service - Climate and Forecast 

This format is a convention for the standardization of NetCDF (data format) files. 

It is sponsored by the "Cooperative Ocean/Atmosphere Research Data Service ", a NOAA/university cooperative for the sharing and distribution of global atmospheric and oceanographic research data sets.

The CF conventions generalize and extend the COARDS conventions. The extensions include metadata that provides a precise definition of each variable. This standard also relaxes the COARDS constraints on dimension order and specifies methods for reducing the size of datasets.


Coriolis project
:French operational in situ data service 

CorSSH
:CORrected Sea Surface Height 

CSA
acronym of:Canadian Space Agency 

CSIRO
:Australia's Commonwealth Scientific and Industrial Research Organisation 

The Commonwealth Scientific and Industrial Research Organisation is Australia's national science agency with 16 scientific divisions included the Oceans and Coasts division.


CTD
:Conductivity-Temperature-Depth 

Type of oceanography probe for measuring temperature and salinity


CTOH
:Centre de Topographie des Océans et de l'Hydrosphère 

Cycle
:Satellite repetitivity 

Jason's (and T/P's) is almost 10 day long. Envisat's 35 days.


Data assimilation
:

Use of data as initial input to a model and during computation to yield results that fit/approximate reality as closely as possible. For example, assimilation of readings from meteorology stations into weather forecasting models generates more reliable results.


Data processing
:

Antennas on the ground receive raw telemetry from satellites. These raw data must be processed by applying corrections and combining them with complementary data before they are usable. Data are processed to different levels:
Level 0: raw telemetry
Level 1: time-tagged data located and corrected for perturbing effects (level 1, 1.5 and 1b data fall into this category)
Level 2: geophysical data (GDR-M) time-tagged, precisely located and corrected for environment effects. Data at this level are used by specialists with a close knowledge of their subject.
Level >2: data ready for immediate use in applications.
level 3: data after validation processes. Some data are removed, due a quality deemed insufficient or due to inadequacity to the surface (e.g. lake data for ocean products). Cross-calibration processes can also be applied, to merged different satellites' data
level 4: gridded data (regular or irregular grid)
Depending on the mission, retracking is performed at level 1 or 2.


Deos
:Delft Institute for Earth-Oriented Space research 

DHU
:Data Handling Unit 

Diode
:Détermination Immédiate d'Orbite par Doris Embarqué 

Real-time onboard Doris system to compute orbit


DLR
:Deutsches Zentrum für Luft- und Raumfahrt 

German Aerospace Center


Doppler effect
:shift between emitted and received frequencies for moving objects 

(or Doppler-Fizeau effect for electromagnetic waves)
The pitch of a sound emitted by a moving object appears to be higher the faster it approaches, and lower the faster it moves away. A good analogy is a stream into which leaves are thrown at regular intervals. As we move upstream towards the source, leaves will flow past us more often. The faster we go, the more leaves we will see. Conversely, as we move downstream away from the source leaves will flow past less often-to the point where we would only see a single leaf when moving at the same speed as the current.
High-pitched sounds have high frequencies, which means we "meet" the sound wave often-as if we were moving towards the source (or it was approaching us); low-pitched sounds have lower frequencies-as if we were moving away. The same principle applies to light rays, which shift towards the longer wavelengths as they move away, and towards the shorter wavelengths as they approach. (Adapted from Evry Schatzmann, Les Enfants d'Uranie)
We can thus determine the velocity of a moving object emitting sound or light waves by measuring the shift between the transmitted and received frequencies. The Doris system achieves precise orbit determination and location by measuring the Doppler shift in this way.


Dry tropospheric correction
:

Permanent gases in the atmosphere (oxygen, nitrogen) slow the radar pulse, generating an error on altimetry measurements of the order of 2.30 meters. The value of the correction is determined from atmospheric pressure data supplied by a meteorological model.


DT
:Delayed Time 

Data produced from the GDR, using the best quality orbit.


Duacs
:Data Unification and Altimeter Combination System 

This system processes data from all altimeter missions (Jason-1, T/P, Envisat, GFO, ERS-1 & 2 and even Geosat) to provide a consistent and homogeneous catalogue of products for varied applications, both for near real time applications and offline studies.


Dynamic topography
:Sea level driven by thermodynamic processes in the ocean 

Sea level driven by thermodynamic processes in the ocean


ECMWF
:European Centre for Medium-range Weather Forecasting 

Eddies
:

Hydrodynamic instabilities in the oceans that form in the wake of currents or are generated by winds. Eddies may persist for weeks or months, and may be tens to hundreds of kilometers across. They penetrate quite deep below the ocean surface and transport heat, salts and nutrients.


EEZ
:Exclusive Economic Zone 

EGU
:European Geophysical Union 

EM
:ElectroMagnetic 

EMB
:Electromagnetic Bias 

Perturbation of the altimeter radar pulse due to the fact that wave troughs reflect more energy than wave crests.


ENSO
:El Niño Southern Oscillation 

 Climatic phenomenon occurring in the Tropics that involves transports of warm (El Niño) or cold (La Niña) water masses from west to east across the Pacific basin. This displacement of water is accompanied by a shift of atmospheric cells, and therefore of winds and monsoons across the Tropics. This oscillation, which has been occurring at irregular intervals for thousands of years, has a global effect on climate. The phenomenon is named "El Niño" (meaning the Christ Child or the Little Boy in Spanish) because warm waters often reach the coast of Peru around Christmas time, often severely disrupting local fisheries.

 


Environment corrections
:

The radar pulse used to measure altimetry is subjected to a number of disturbances as it passes through the atmosphere and when it is reflected by the sea surface.


EnviSat
:ENVIronmental SATellite 

Earth-observing satellite (Esa)


ERM
:Exact Repeat Mission (Geosat) 

Phase of the Geosat mission during which the satellite was put into a 17-day repeat orbit to study the oceans.


ERS
:European Remote Sensing satellite (ERS-1, ERS-2) 

Earth-observing satellites (Esa)


Esa
:European Space Agency 

The European Space Agency is a space agency founded in 1975. It is responsible of space projets for 17 european countries.


EU
:European Union 

Eumetsat
:European Organisation for the Exploitation of METeorological SATellites 

  


F-DAC
:French-Distribution and Archiving Center (F-DAC) 

Facilitate communication with the ground segment Envisat, archiving and distribution of the Envisat products under French responsibility.

 

 


F-PAC
:French-Processing and Archiving Center (F-PAC) 

FDGDR
:Fast-Delivery Geophysical Data Record 

RA-2 Geophysical Data Record product containing radar range and orbital altitude, wind speed, wave height, water vapour from the radiometer and geophysical corrections. Product delivers by Esa within 3 hours after the measurement.


FDM
:Fasham Ducklow McKelvie 

Fasham Ducklow McKelvie Ecosystem model.


FDP
:Fast Delivery Product 

FES
:Finite Element Solution 

FNMOC
:Fleet Numerical Meteorological & Oceanographic Center (US Navy)  

FNOC
:Fleet Numerical Oceanographic Center 

Foam
:Forecasting Ocean-Atmosphere Model 

Fram
:Fine Resolution Antarctic Model 

FTLRS
:French Transportable Laser Ranging Station 

GCM
:General Circulation Model 

GCOS
:Global Climate Observing System 

GDR
:Geophysical Data Record 

Level 2 data.

Available GDR data.


Geodesy
:

It's a is the scientific discipline  in the Earth sciences, that deals with the measurement and representation of the Earth, including its gravity field.

 


Geoid
:

The shape of the sea surface assuming a complete absence of perturbing forces (tides, wind, currents, etc.). The geoid reflects the Earth's gravitational field (it is an equipotential surface) and varies in height by as much as 100 meters over distances of several thousand kilometers due to uneven mass distribution within the planet's crust, mantle and core. Other, less pronounced, irregularities are also visible over smaller distances. These reflect the ocean's bottom topography.

 


Geophysical corrections
:

The radar pulse used to measure altimetry is subjected to a number of disturbances as it passes through the atmosphere and when it is reflected by the sea surface.


Geosat
:Geodetic & Oceanographic SATellite 

Altimetric satellite (US Navy).


Geostrophic circulation
:

Ocean circulation generated by the balance between the horizontal pressure gradient forces exerted by water masses and the effect of acceleration due to the Earth's rotation.


Gewex
:Global Energy and Water cycle Experiment 

Global Energy and Water cycle Experiment (WCRP)


GFDL
:Geophysical Fluid Dynamics Laboratory 

GFO
:GEOSAT Follow-On 

Altimetric Satellite (US Navy).


GFZ
:GeoForschungsZentrum 

Germany's National Research Centre for Geosciences


GIA
:Glacial Isostatic Adjustment 

The continents once covered by ice during last Ice Age are still reacting to the melting of this ice by going up (post glacial rebund).


Globec
:Global Ocean Ecosystem Dynamics  



GLOSS
:Global Sea Level Observing System  



GM
:Geodetic Mission 

Phase of the Geosat mission during which the satellite's orbit was designed to study the geoid.


Goce
:Gravity field and steady-state Ocean Circulation 

Godae
:Global Ocean Data Assimilation Experiment 

Goos
:Global Ocean Observation System 

GPS
:Global positionning System 

GPSDR
:Global Positioning System Demonstration Receiver 

One of three positioning systems on Topex/Poseidon that uses the GPS to determine the satellite's position.

See also: GPS, Doris, LRA, TRSR, Topex/Poseidon


Grace
:Gravity Recovery and Climate Experiment 

Greenhouse effect
:

A good proportion of the heat penetrating the Earth's atmosphere is not reflected back into space but is "trapped" by clouds and water vapor. This heat is thus returned to the surface, maintaining an average temperature of 15°C on Earth. Without it, the temperature would be nearer -18°C. Increasing quantities of certain gases in the atmosphere-called greenhouse gases-such as carbon dioxide are thought to amplify this phenomenon, leading to an increase in temperature on the surface of the globe.

 


GRGS
:Groupe de Recherche en Géodésie Spatiale  

Ground segment
:

The teams, hardware and software involved in controlling a satellite and in retrieving and processing its data.


GSFC
:Goddard Space Flight Center 

Goddard Space Flight Center (Nasa).


Gulf Stream
:

Western boundary current of the subtropical gyre. The Gulf Stream is a strong current that transports warm waters from the Gulf of Mexico up the south coast of the United States to the Mid-Atlantic Ocean.

 


H1/3
:Significant Wave Height  

See Significant Wave Height (SWH).


HCA
:Heat Content Anomaly 

HF
:High Frequency 

HRX
:High Resolution XBT/XCTD 

Hycom
:Hybrid coordinate model 

IAT
:International Atomic Time 

IB
:Inverted Barometer 

Correction applied to allow for atmospheric forcing of the ocean surface. The sea level is lower when atmospheric pressure is high, and higher when atmospheric pressure is low.


IDRIS
:Institut pour le Développement de la Recherche en Informatique Scientifique 

IDS
:International Doris Service 

IERS
:International Earth Rotation Service 

IES
:Inverted Echo Sounder 

Ifremer
:Institut Français de Recherche et d'Exploitation de la MER 

French Ocean Agency


IFRTP
:Institut Français de Recherche et Technologie Polaires 

called now IPEV, Institut Paul-Emile Victor, french Institute for Polar Research and Technology


IGBP
:International Geosphere Biosphere Programme 

IGDR
:Interim Geophysical Data Record(s) 

IGDR-M: IGDR Mixtes (Merged GDR);  IGDR-P: IGDR-PoseidonIGDR-T: IGDR-Topex


IGN
:Institut Géographique National 

French National Geographical Institute


IGS
:

International GPS Service for Geodynamics.


IM
:Instrument Module 

IMG
:Institut de Mécanique de Grenoble 

Insu
:Institut National des Sciences de l'Univers 

IOC
:Intergovernmental Oceanographic Commission (UNESCO) 

IOD
:Indian Ocean Dipole 

IOD is known as atmosphere-ocean interaction phenomenon, with large impacts on surrounding areas.


Ionosphere
:

Layer of the upper atmosphere where electron and ionization activity is particularly high.
Electromagnetic waves are subjected to a number of perturbing effects as they pass through the ionosphere.

 


Ionospheric correction
:

The altimeter radar signal is delayed as it travels through the ionosphere. Free electrons slow the radar pulse, causing an error on altimetry measurements of the order of 0 to 30 centimeters. The value of this correction is determined by combining range measurements acquired at two different frequencies (Topex and Poseidon-2 altimeters), as it is inversely proportional to the square of the frequency. For mono-frequency altimeters such as that used on the ERS satellites, this value is determined using a statistical model of the ionosphere.


IPCC
:Intergovernmental Panel on Climate Change 

Ipev
:Institut Paul-Emile Victor 

french Polar Institute


IRD
:Institut de Recherche pour le Développement 

French Research Institute for Development (ex-ORSTOM).


Isro
:Indian Space Research Organization 

ITCZ
:InterTropical Convergence Zone 

ITF
:Indian ocean ThroughFlow 

ITRF
:International Terrestrial Reference Frame 

JAMSTEC
:Japan Agency for Marine-Earth Science and Technology 

JAMSTEC contributes to the advancement of academic research in addition to the improvement of marine science and technology by proceeding the fundamental research and development on marine,


Jason
:Altimetric missions 

Altimetric missions (Cnes/Nasa), follow-on of Topex/Poseidon. Jason-1 was launched on December 7, 2001 and Jason-2 was launched on June 20, 2008.


JAXA
:Japan Aerospace Exploration Agency 

JGM
:Joint Gravity Model 

JGR
:Journal of Geophysical Research 

JMR
:

Jason-1 Microwave Radiometer.
See also : Satellite altimetry, Radiometer, Environment corrections, Jason-1, TMR


JPL
:Jet Propulsion Laboratory (Nasa) 

KE
:Kuroshio Extension 

Keops
:KErguelen Ocean and Plateau compared Study 

Scientific cruises around the Kerguelen Island (Indian Ocean) funded by the Agence Nationale de la Recherche (ANR), the Centre National de la Recherche Scientifique / Institut National des Sciences de l'Univers (CNRS / INSU) and the Institut Polaire Paul-Emile Victor (IPEV). 
Its purpose is to measure the biological activity depending on the chemical composition and the impact on the biogeochemical cycles.


KERFIX
:Kerguelen Fixed station 

KF
:Kalman Filter 

KNMI
:Koninklijk Nederlands Meteorologisch Instituut  

Royal Meteorological Institute of Netherlands.


Kuroshio current
:

Western boundary current of the subtropical gyre. The Kuroshio Current is a strong current that transports warm waters from the China Sea and the Philippines up past Japan to the Mid-Pacific Ocean. It is the counterpart of the Gulf Stream in the North Atlantic.

 


La Niña
:

See ENSO

 


LAS
:Live Access Server 

LDEO
:

Lamont-Doherty Earth Observatory.

 

 


Legi
:

Laboratoire des écoulements Géophysiques et Industriels.

 


Legos
:Laboratoire d'Etudes en Géophysique et Océanographie Spatiales 

The LEGOS (UMR 5566) is a joint research laboratory headed by : the Centre National d'Etudes Spatiales (CNES), the Centre National de la Recherche Scientifique (CNRS), the Institut of Recherchepour le Développement (IRD) and the Paul Sabatier University (UPS).

Its study fields are related to the environment focused on the physical ocean, marine geochemistry and biogeochemistry, spatial hydrology and dynamics of the polar ice caps, using remote sensing and five or observing networks.

 


LEO
:

Low Earth Orbit  

 

 


LF
:

Line Feed

 


LOD
:

Length-Of-Day


LodyC
:

Laboratoire d'Océanographie DYnamique et de Climatologie, called now, LOCEAN (Laboratoire d'Océanographie et du Climat : Expérimentation et Approches Numériques).

 


LPO
:

Laboratoire de Physique des Océans.

 

 


LPT
:Light Particles Telescope 

Dosimeter used to improve knowledge of particularly aggressive radiation. Passenger instrument onboard Jason-2 and Jason-3. JAXA/Cnes contribution.


LRA
:Laser Retroreflector Array 

One of three positioning systems on Topex/Poseidon and Jason. The LRA uses a laser beam to determine the satellite's position by measuring the round-trip time between the satellite and Earth to calculate the range.

 


LSG
:

Large-Scale Geostrophic.

 

 

 


LWR
:Long Wavelength Error 

MADT
:Maps of Absolute Dynamic Topography. 

MCC
:

Maximum Cross Correlation.


MDT
:Mean Dynamic Topography 

the ocean topography due to the major currents.

 

 


Mercator Ocean
:

Joint project to develop a high-resolution model of the global oceans, involving Cerfacs, Cnes, CNRS, Ifremer, Météo France, IRD and Shom.

 

 


Météo France
:

French Meteorological Office

 


MFS
:

Mediterranean Forecasting System


MFSPP
:

Mediterranean Forecasting System Pilot Project


Micom
:

Miami Isopycnic-Coordinate Ocean Model.


MIT
:

Massachusetts Institute of Technology.

 


ML
:

Mixed-layer


MMS
:

Multimission Modular Spacecraft.

 


MNATL
:

Mercator North Atlantic prototype.

 


MNHN
:

Muséum National d'Histoire Naturelle.

 


Modeling
:

Modeling a phenomenon involves identifying its main characteristics and expressing them mathematically to better understand and, above all, predict how the phenomenon is likely to evolve.

 


MOE
:

Medium Orbit Ephemeris.

 


MOM
:

Modular Ocean Model.


MOTEVAS
:

Mouvements Océaniques et TEctoniques Verticaux par Altimétrie Spatiale.

 


MPIFM
:

Max-Planck Institute für Meteorologie.

 


MSL
:Mean Sea Level 

The sea surface height averaged across all the oceans of the globe. An increase in the mean sea level is an indicator of a possible global warming.Mean Sea Level

 


MSLA
:Maps of Sea Level Anomalies 

MSS
:

Mean Sea Surface
Permanent component of the sea surface height. The mean sea surface comprises a geoid contribution (~100 m) and a permanent circulation contribution (~1 m).

 


MSSA
:

Multi-Channel Singular Spectral Analysis.

 

 


MSWS
:

Meridional Surface Wind Stress.

 

 


MVEOF
:

Multi-variate empirical orthogonal function.

 


MVR
:Mesureur de Vitesse Radiale 

Radial Speed measurer


MWR
:

MicroWave Radiometer (onboard ERS and Envisat).

 


MyOcean
:

MyOcean is a European project dedicated to operational oceanography. MyOcean Service provides the best set of information available on the Ocean for the large and regional scales (European seas), based on the combination of space and in situ observations, and their use into models: temperature, salinity, currents, ice extent, sea level, primary ecosystems...
The Sea Level observation data available within MyOcean are Ssalto/Duacs along-track data.

 


NAO
:

North Atlantic Oscillation.

 


Nasa
:National Aeronautics and Space Administration 

The National Aeronautics and Space Administration (Nasa) is the space agency of the United States government, established in 1958.


NATL3
:

North Atlantic

 


NAVOCEANO
:

NAVal OCEANographic Office.

 


NBC
:North Brazil Current 

North Brazil Current

 

 


NCAR
:National Center for Atmospheric Research 

NCEP
:National Center for Environmental Prediction 

(Noaa)

 


NDBC
:National Data Buoy Center 

(Noaa)

 


NEC
:North Equatorial Current 

NECC
:North Equatorial Counter Current  

NERC
:Natural Environment Research Council  

NERC is the UK's main agency for funding and managing research, training and knowledge exchange in the environmental sciences.

 

 

 


Nesdis
:National Environmental Satellite Data & Information Service 

(Noaa)

 


NetCDF
:network Common Data Form 

Nima
:National Imagery and Mapping Agency 

(US)

 


Niña
:Niña (La) 

See ENSO.

 


Niño
:Niño (El) 

See ENSO.

 


NLOM
:Naval Research Laboratory Ocean Model  

NMC
:

National Meteorological Centre.


Noaa
:National Oceanic and Atmospheric Administration 

The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the studies of the oceans and the atmosphere.


Nogaps
:Navy Operational Global Atmospheric Prediction System 

Noise
:

Statistical quantity used to estimate the inherent error on measurements induced by the instrument itself.

 

 


Noss
:North Sea level System monitoring 

.

 


NPC
:North Pacific Current 

.

 


NRA
:Nasa Radar Altimeter 

See also: Topex, Poseidon, Topex/Poseidon

 


NRCS
:Normalized Radar Cross Section 

.

 


NRL
:Naval Research Laboratory  

.

 


NRT
:Near-Real Time 

Data produced from the IGDR (i.e. using data computed with a preliminary orbit).


NScat
:Nasa SCATterometer 

.

 


NTF
:National Tidal Facility 

(Australia) .

 


NWP
:

Met Office's numerical weather prediction.

 


OCA
:Observatoire de la Côte d’Azur  

.

 


Ocean-atmosphere coupling
:

The ocean and atmosphere are mutually interdependent. In particular, water that evaporates from the ocean causes the atmosphere to become hotter and more humid. This phenomenon affects atmospheric movements (winds), which in turn affect ocean circulation and so on: the temperature of air masses in contact with the ocean is modified and, conversely, ocean currents are driven by dominant winds. These ocean-atmosphere interactions are a major factor in weather forecasting and a key element in our understanding of climate.
Climate

 


ODES
acronym of:Online Data Extraction Service 

The Online Data Extraction Service is  a data access service dedicated to along-track data, with the ability to extract instrumental and geophysical subset of parameters on-the-fly from  geographical and temporal selections.

odes.altimetry.cnes.fr

 


OER
:Orbit Error Reduction 

OGCM
:Ocean General Circulation Model 

.

 


OI
:Optimal Interpolation 

Technique used to grid data from along-track datasets

 


OIS
:Ocean Information System 

.

 


OPA
:Océan Parallélisé 

.

 


OPAVAR
:

 Variational data assimilation system based on the OPA Ocean General Circulation Model.

 


Orbitography
:

 The study of satellite orbits. Very precise determination of a satellite's exact position is a key factor in altimetry. On Topex/Poseidon and Jason, three orbit determination systems are used.

 


ORCA
:

 Global configuration of the OPA model.

 


OSDR
:Operational Sensor Data Record(s) 

.

 


OSTM
:Ocean Surface Topography Mission 

 name of the Jason-2 satellite mission


Outreach
:

 program to inform the general public about the projects. 

 


Ovide
:Observatoire de la variabilité interannuelle et décennale en Atlantique Nord 

The Ovide project aims at documenting and understanding the variability of the circulation and water mass properties in the northern North Atlantic within the context of global change.


PACJET
:

 Pacific Landfalling Jets Experiment.


PALM
:Projet d'Assimilation par Logiciel Multiméthode 

.

 


PD
:Path Delay 

.

 


PELOPS
:Projet d'ÉLaboration d'une Océanographie opérationnelle des Pêches  

.

 


Permanent circulation
:

 Steady state of ocean currents in an idealized unchanging atmospheric system.

 


PGGS
:Proteus Generic Ground System 

.

 


PI
:Principal Investigator 

 Person in charge of a research team working on a science project.


PIRATA
:Pilot Research Moored Array in the Tropical Atlantic 

.

 


PISTACH
:Prototype Innovant de Système de Traitement pour les Applications Côtières et Hydrologiques 

The PISTACH project is funded by Cnes as part of OSTM/Jason-2 project to improve satellite radar altimetry product over coastal areas and continental waters.


PNEDC
:Programme National d'étude du Climat 

 (Woce-France).

 


PNTS
:Programme National de Télédétection Spatiale 

.

 


Po-Daac
:Physical Oceanography – Distributed Active Archive Center 

.

 


POAC
:Pôle Océan, Altimétrie et Climat 

 Ocean, Altimetry and Climate Group.

 


POCC
:Project Operation Control Center 

.

 


POCM
:Parallel Ocean Circulation Model 

.

 


POD
:Precise Orbit Determination 

.

 


POE
:Precise Orbit Ephemeris 

.

 


POL
:Proudman Oceanographic Laboratory 

.

 


POMME
:Programme Océan Multidisciplinaire MésoEchelle  

.

 


POP
:Parallel Ocean Program  

Poseidon
:

One of the two altimeters onboardTopex/Poseidon (Cnes); Poseidon-2 is the Jason-1 altimeter.
Poseidon-2


PRARE
:Precise Range and Range-rate Equipement  

.

 


Proteus
:Plate-forme Réutilisable pour l'Observation, les Télécommunications et les Usages Scientifiques 

 Minisatellite bus developed in France for Jason-1 and other missions.

 


PSMSL
:Permanent Service for Mean Sea Level 

.

 


psu
:Practical Salinity Unit  

 Unit used to measure salinity in the ocean. One psu is one gram of salts per thousand grams of ocean, or about one gram per liter of water. Typical salinity in the ocean is 35 psu.

 


QG
:Quasi-Geostrophic 

.

 


QuikScat
:Nasa's Quick Scatterometer 

.

 


R&D
:Research and Development 

.

 


Radiometer
:

 Passive instrument that detects and measures radiant energy, usually in the microwave, infrared and near-infrared wavebands.
Radiometers flown on altimetry satellites help us to measure water vapor and liquid water content in the atmosphere. These measurements are used to apply corrections to altimetry data. The radiometer's antenna collects radiation reflected by the ocean.
The amount measured depends on surface winds, ocean temperature, salinity, foam, absorption by water vapor and clouds, and other factors. To determine atmospheric water vapor content accurately, the surface and cloud contributions must be filtered out from the signal received by the radiometer. For this reason, different signal frequencies are used to increase sensitivity to each of these parameters. By combining measurements acquired at both frequencies, we can extract the water vapor signal.

 


Reference ellipsoid
:

 Arbitrary reference surface that is a raw approximation of the Earth's shape, which is basically a sphere "flattened" at its poles. The length of one of the axes at the Equator is chosen so that the ellipsoid coincides at this latitude with the mean sea level. For example, the ellipsoid used by the Topex/Poseidon mission has a radius of 6378.1363 km and a flattening of 1/298.257.

 


RIAM
:Research Institute for Applied Mechanics 

.

 


RMS
:Root Mean Square 

Root Mean Square


SAFDE
:SubAntarctic Front Dynamics Experiment  

.

 


Salinity
:

 The quantity of salts/salt content (sodium, potassium, silver salts, etc.) in sea water. Salinity plays an important role in the distribution and dynamics of water masses. In particular, it is a factor that affects downwelling of water to the ocean depths: highly saline water is more dense and therefore has a greater tendency to descend towards the ocean floor.

 


Salp
:Service d'Altimétrie et de Localisation Précise 

SAR
:Synthetic Aperture Radar  

.

 


Saral
:Satellite with ARgos and ALtika 

satellite altimetry
:

Technique for measuring height. Satellite altimetry measures the time taken by a radar pulse to travel from the satellite antenna to the surface and back to the satellite receiver. Combined with precise satellite location data, altimetry measurements yield sea-surface heights.


SEAS
:Surveillance de l'Environnement Assistée par Satellite  

.

 


Seasat
:

 Satellite for oceans observation(1978).

 


SeaWIFS
:Sea-viewing Wide Field-of-view sensor 

.

 


SEEK
:Singular Evolutive Extended Kalman 

.

 


SELF II
:Sea Level Fluctuations II  

.

 


SESAM
:

 System of sequential assimilation modulus.

 


SFDU
:Standard Formatted data Unit 

.

 


SGDR
:Sensor Geophysical Data Record(s) 

.

 


Shom
:Service Hydrographique et Océanographique de la Marine 

.

 


SIE
:Sea Ice Extend 

.

 


Sigma 0
:

 or sigma-naught
reflexivity coedfficient of the radar wave on the surface.

 


SIMB
:Service d'Installation et de Maintenance des Balises 

.

 


SLA
:Sea Level Anomaly 

Variations of the sea surface height with respect to a several-year mean or a mean sea surface. SLAs include seasonal variability.

The SLAs allow us to monitor ocean variability due to seasonal variations and climatic phenomena such as El Niño. Sea level variability (the standard deviation over time) is somewhere between 2-3 cm and 60 cm, depending on energy levels in different parts of the ocean.


SLH
:Sea Level Height 

.

 


SLP
:Sea Level Pressure  

.

 


SLR
:Satellite Laser Ranging 

.

 


SMMR
:Scanning Multichannel Microwave Radiometer  

.

 


SMO
:Surface Moyenne Océanique  

 Mean Sea Surface.

 


Smos
:Soil Moisture and Ocean Salinity 

.

 


Soap
:Système Opérationnel d'Analyse et de Prédiction 

 Model developed by Shom, the French Navy's hydrography and oceanography department, to forecast ocean circulation in the Northeast Atlantic.
See also:
-  Soprane

 


SOC
:Southampton Oceanography Center 

 also called NOCS, National Oceanography Center, Southampton.

 


SOD
:Service d'Orbitographie Doris 

 (Cnes).

 


SOPAC
:Scripps Orbit and Permanent Array Center  

.

 


Soprane
:Système Océanique de Prévision en Atlantique Nord-Est 

 Ocean Forecasting System on the Eastern-North Atlantic
Model used to forecast ocean currents and eddies. The successor to Soap.

 


Spot
:Système Pour l'Observation de la Terre 

.

 


SSA
:Singular Spectrum Analysis  

.

 


SSALT
:Solid State radar ALTimeter  

.

 


Ssalto
Segment Sol multimissions d'ALTimétrie, d'Orbitographie et de localisation précise 

The Ssalto multimission ground segment (Segment Sol multimissions d'ALTimétrie, d'Orbitographie et de localisation précise) encompasses ground support facilities for controlling the Doris and Poseidon instruments, for processing data from Doris and the Topex/Poseidon, Jason-1 and Envisat-1 altimeters, and for providing user services and expert altimetry support.

 


SSB
:Sea State Bias 

 Bias due to the sea-surface state, which consists of two components: electromagnetic bias and tracker bias.

 


SSDP
:Segment Sol Doris/Poseidon 

 Doris/Poseidon ground segment.

 


SSDT
:Sea Surface Dynamic Topography  

.

 


SSH
:Sea Surface Height 

Height of the sea surface with respect to a reference. In altimetry, usually, sea surface height with respect to the reference ellipsoid.


SSHA
:Sea Surface Height Anomalies 

 see Sea Level Anomalies (SLA).

 


SSM/I
:Special Sensor Microwave/Imager 

.

 


SSS
:Sea Surface Salinity 

.

 


SST
:Sea Surface Temperature 

 Water temperature at the ocean surface. The SST can be measured by satellite-based infrared radiometers.
See also:
-  Radiometer
-  AVHRR
-  ATSR

 


STF
:Subtropical Front 

.

 


SVD
:Singular Value Decomposition 

.

 


SWH
Significant wave height 

Symbol Hs or H1/3.
The significant wave height is obtained by analyzing the shape and intensity of the altimeter radar beam reflected from the sea surface (radar echo). A long time delay in the return signal indicates that waves are high and, conversely, a short delay indicates that the sea surface is calm.


SWS
:Surface Wind Stress 

.

 


SWT
:Science Working Team 

 Team working on the Topex/Poseidon and Jason-1 missions that meets at least once a year.

 


T-S
:Temperature - Salinity 

.

 


T/P
:Topex/Poseidon 

.

 


TAO
:Tropical Atmosphere Ocean 

.

 


TB
:Brightness Temperature  

.

 


TBC
:To Be Confirmed 

.

 


TDRSS
:Tracking and Data Relay Satellite System 

.

 


Tercile
:

 Terciles are range of values of a physical variables (e.g. precipitation, temperature...) defined so as to sort into 2 sections 1/3 of the lower, of the average and higher values of a distribution that could represent a climatology.

 


TGS
:Topex Ground Segment 

.

 


Thermocline
:

 Zone between the colder water of the ocean depths and warmer surface water. Large temperature variations occur with depth in the thermocline zone. Near the surface, however, where water is always in motion, and in the ocean depths where there is no source of heat, the water temperature is fairly uniform.

 


Thermohaline circulation
:

 Large-scale global ocean circulation driven by variations in the temperature and salinity of water masses. Cooled and saline waters downwell at high latitudes (off the coast of Norway and Greenland). Waters warmed in the Tropics upwell to the surface, where they are cooled, and so on. It is estimated that a single water molecule takes about 1,000 years to complete the circuit.

 


Tide
:

Ocean tides can now be gauged to within 2 cm, thanks largely to altimetry. This has helped to improve our understanding of Earth-Moon interactions, such as the Moon's impact on the length of the day on Earth.

 

 


Timed
:Thermosphere Ionosphere Mesosphere Energetics & Dynamics 

 Satellite (Nasa), that was launched with Jason-1.

 


TIPE
:

  French educational program.

 


TIW
: Tropical instability wave 

.

 


TMI
:TRMM Microwave Imager 

.

 


TMR
:Topex Microwave Radiometer 

 Radiometer onboard Topex/Poseidon.

 


Toga
:Tropical Ocean - Global Atmosphere 

.

 


TOP
:Target Operational Period 

.

 


TOPAZ
:

 Towards an operational prediction system for the North Atlantic and European coastal zones.

 


Topex
:Ocean TOPography Experiment 

 One of the 2 altimeters (Nasa) onboardTopex/Poseidon.

 


Topex/Poseidon
:

 Altimetric satellite (Nasa/Cnes).

 


TOVS
:TIROS Operational Vertical Sounder 

.

 


TPEM
:Topex/Poseidon Extended Mission 

.

 


TRMM
:Tropical Rainfall Measuring Mission 

.

 


TRSR
:Turbo Rogue Space Receiver 

UKMO
:United Kingdom Meteorological Office 

.

 


UMR5566
:Unité Mixte de Recherche n°5566 du CNRS 

 (ex UMR n°39).

 


USO
:Ultra-Stable Oscillator 

UTC
:Universal Time Coordinated 

 Timekeeping system that relies on atomic clocks to provide accurate measurements of the second, while remaining coordinated with the Earth's rotation, which is much more irregular. To stay synchronized, UTC has to be adjusted every so often by adding one second to the day, called a leap second, usually between June 30 and July 1, or between December 31 and January 1. This is achieved by counting 23h59'59", 23h59'60" then 00h00'00". This correction means that the Sun is always at its zenith at noon exactly (accurate to the second).

 


VLBI
:Very Long Baseline Interferometry 

.

 


VLF
:Very Low Frequency 

.

 


VMS
: Vax virtual Memory operating System 

.

 


VOS
:Voluntary Observing Ship 

.

 


WAM
:Wave Model 

WBC
:Western Boundary Current 

.

 


WCRP
:World Climate Research Program  

The World Climate Research Programme, sponsored by the International Council for Science (ICSU), the World Meteorological Organization (WMO) and the Intergovernmental Oceanographic Commission (IOC) of Unesco, is uniquely positioned to draw on the totality of climate-related systems, facilities and intellectual capabilities of more than 185 countries. Integrating new observations, research facilities and scientific breakthroughs is essential to progress in the inherently global task of advancing understanding of the processes that determine our climate.

The two overarching objectives of the WCRP are:

  1. to determine the predictability of climate; and
  2. to determine the effect of human activities on climate.

western boundary current
:

Wet troposheric correction
:

 Water vapor in the atmosphere slows the radar pulse. This effect can generate mean errors of the order of 15 centimeters on altimetry measurements. The value of the correction applied is determined using measurements by radiometer on the satellite.

 


WFF
:Wallops Flight Facility 

.

 


Wittex
:Water Inclination Topography and Technology Experiment 

.

 


WMO
:World Meteorological Organization 

.

 


WOA
:World Ocean Atlas 

.

 


Woce
:World Ocean Circulation Experiment 

The World Ocean Circulation Experiment (Woce) was a component of the World Climate Research Program and remains the most ambitious oceanographic experiment undertaken to-date.The aims of the programme were to establish the role of the oceans in the earth's climate and to obtain a baseline dataset against which future change could be assessed. Sophisticated numerical ocean models were also developed to provide a framework for the interpretation of the observations and for the prediction of the future ocean state.


WOD
:World Ocean Database 

.

 


WSG
:Western Subarctic Gyre 

.

 


WSOA
:Wide-Swath Ocean Altimeter 

Project of altimeter-interferometer instrument; planned at first to be onboard Jason-2


XBT
:eXpendable Bathy Thermograph 

or eXpendableBathyConductivity-Temperature-Depth.

 


ZSWS
:Zonal Surface Wind Sress 

.

 


ZWD
:Zenith Wet Delay 

.

 


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