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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...)

 

CMEMS
Copernicus Marine and Environment Monitoring Service
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
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 inadequacy 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-Poseidon;  IGDR-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)
KaRIn

KaRIn is the main  instrument on the Swot satellite, it is a Ka band wide-swath interferometric altimeter.

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
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.

SWOT
Surface Water and Ocean Topography

 .

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.

 

Test
test
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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