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Acronyms & Glossary


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This section contains information on terms, phrases and abbreviations used by the NOAA CoastWatch. It's purpose is to aid the general public in better understanding CoastWatch data products.





A

ACSM

ACSPO Clear Sky Mask

ACSPO

Advanced Clear Sky Processing for Oceans (Processing system for NOAA Sea Surface Temperature products)

aerosol

Tiny droplets or particles in the atmosphere

algorithm

Series of calculations following a set of rules

Altimeter

Instrument used to measure the altitude of an object above sea level.

AMSU

Advanced Microwave Sounding Unit

anomaly

Difference or variability from a defined reference point

AOD

Aerosol Optical Depth

AOT

Aerosol Optical Thickness

API

Application program interface

apogee

The point in a satellite's orbit furthest away from Earth.

ArcGIS

Proprietary global information system mapping software

ASCAT

Advanced SCATterometer - a real aperture radar instrument aboard EUMETSAT’s Metop series of three polar orbiting meteorological satellites

ASCII

American Standard Code for Information Interchange, a computer format

ATOVS

Advanced TIROS Operational Vertical Sounder (suite of sounding instruments including AMSU-A, AMSU-B and HIRS/3).

AVHRR

Advanced Very High Resolution Radiometer, on NOAA polar orbiting satellites for measuring sea surface temperature and other parameters

azimuth

An arc of the horizon measured between a fixed point (as true north) and the vertical circle passing through the center of an object.



B

backscatter

The portion of power scattered back in the incident direction.

band

Range of wavelengths

blackbody

A hypothetic body that completely absorbs all wavelengths of thermal radiation incident on it. Such bodies do not reflect light, and therefore appear black if their temperatures are low enough so as not to be self-luminous.

blended

Indicates a mix of satellite and in situ observations

BRDF

Bi-directional Reflection Distribution Function

BUFR

Binary Universal Form for the Representation of meteorological data.

buoy

Structure anchored at the bottom, floating (moves, but chained) at the surface, sometimes used as a platform from which to deploy oceanographic instruments.



C

C-band

The portion of the electromagnetic spectrum ranging from 4-8 GHz.

Cal/Val

Calibration and Validation

CDAT

CoastWatch Data Analysis Tool

CEOS

Committee on Earth Observation Satellites (an international body)

CERES

Clouds and Earth's Radiant Energy System

chlorophyll-a

The pigment in plants and phytoplankton that is responsible for photosynthesis

CLASS

Comprehensive Large Array-data Stewardship System, NOAA’s data archive

Climate Monitoring

Monitoring changes in climate trends in satellite data.

Coordinated Universal Time (UTC)

By international agreement, the local time at the prime meridian, which passes through Greenwich, England (previously know as GMT). The time used by EUMETSAT on data/products and satellite operational events.

Copernicus

Large, long term European Commission program for environmental Earth observations, including observations from remote sensing satellites and in situ observations

coral

A plant, animal and mineral assemblage living together which functions as a colonial "organism"



D

decadal

Data occurring over a 10-year period.

diurnal

A day night cycle

DMSP/SSMI

Special sensor microwave/imager (SSM/I) on board the United States Air Force Defense Meteorological Satellite Program (DMSP)

DOI

Digital object identifier



E

ecology

The study of the relationships among organisms and environment

ecosystem

Unit of interacting living resources and environment

ecotoxicology

The study of effects of harmful substances on organisms and ecosystems

eddy, eddies

Swirl of water counter to the predominant current

empirical

Based on observations rather than theory

ESA

European Space Agency

ESRI

Company that make ArcGIS software

EUMETCast

EUMETSAT's Data Distribution System, which broadcasts data to users.

EUMETSAT

European Organisation for the Exploitation of Meteorological Satellites



F

FAO

Food and Agriculture Organization of the United Nations; Publishes an annual report on the state of world fisheries and aquaculture

FAQ

Frequently Asked Questions

flux

Continuous exchange

forecast

Prediction or estimation; at NOAA, a forecast indicates that human judgment is involved in the analytical process whereas a prediction could be simply the output of a computer model, for example

FTP

A computer transfer protocol



G

GAC

Global Area Coverage

GCM

General Circulation Model, a numerical model that represents physical processes in the ocean and atmosphere (or other fluid environments)

GDS2

Graphic Database System; a computer file format

GEO-POLAR

Indicates a blend of data from geostationary orbiting and polar orbiting satellites

geostationary orbit

A geo-synchronous orbit such that the satellite appears to be stationary above the primary (e.g., Earth)

GFS

Global Forecast System; a weather forecast model at NOAA

GHRSST

Group for High Resolution Sea Surface Temperature; international professional group which sets standards for SST

granule

A packet of data of a standardized size/coverage area (for example, a set number of scans rows (which also relates to time) along a set swath width) from a satellite sensor. For example, A VIIRS SNPP granule is 48 scans (approximately 85 seconds, which is approximately 570 km) x approximately 3,040 km



H

HAB

Harmful Algal Bloom; a fast growing accumulation of toxic algae

HDF

Hierarchical Data Format

HIRS/3

High Resolution Infra Red Radiation Sounder

hydrology

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water on or below the land surface.



I

IFOV

Instantaneous Field Of View

In plane maneuver

Operation implementing, by activation of thrusters, a change of the orbital velocity of a satellite in the in-flight direction (and consequently a change of the semi-major-axis of the orbit). These maneuvers are used to compensate for the orbital perturbations caused by the drag (for Low Earth Orbit satellites, leading to orbital decay) or the gravity field asymmetry (for geostationary satellites, leading to longitude drift); as the eccentricity of the orbit is also modified at the same time, these maneuver can be used to compensate for the orbital perturbations caused by the solar radiation pressure (leading to a change of the orbital eccentricity).

inclination

Angle between orbital plane of satellite and equatorial plane of reference (e.g., Earth)

Infrared radiation (IR) and Infrasatellite imagery

IR is the region of the electromagnetic spectrum adjacent to that of visible light, but with longer wavelengths (0.65-10 micrometers, typically). IR satellite imagery senses surface and cloud top temperatures by measuring the wavelength of electromagnetic radiation emitted from these objects.

iQuam

Quality monitoring system for in situ sea surface temperature observations

IR

Infra Red

ISRO

National Remote Sensing Centre Indian Space Research Organisation



J

Jason-2, Jason-3

International, multi-agency satellite missions for ocean altimetry. Named for Greek mythological Jason and the Argonauts

JPL

Jet Propulsion Laboratory (NASA)

JPSS

Joint Polar Satellite System

JRC

Joint Research Centre (European Commission)



K

Kd490

Diffuse attenuation coefficient at the 490 nm wavelength

Ku-Band

The portion of the electromagnetic spectrum ranging from 12-18 GHz.



L

L0, L1, L2, L2P, L3, L4

Levels of data processing involved in making satellite "products". These are not fixed definitions but here is an idea of what they might indicate: beginning from raw computer bits and bytes (L0), to calibrated instrument measurement (L1), to environmentally relevant geophysical parameters of interest (L2), to parameters from a single sensor that have been spatially or temporally binned or mapped or gridded for example (L3) and products derived from a combination of multiple sensors or a combination of satellite and in situ observations. GHRSST uses additional qualifiers to indicate other processing level details. L2p, L2u, L3p and others have specific meanings for GHRSST sea surface temperature. See the GHRSST product site (https://www.ghrsst.org/ghrsst-data-services/products/) for details.

latency

The amount of time delay between satellite observation and when a satellite product is available to be used for an application

LEO

Lower Earth Orbit

LUT

Look up tables



M

MCSST

Multi-channel sea surface temperature

mercator

cylindrical map projection

meridian

line of longitude

MERIS

MEdium Resolution Imaging Spectrometer (ESA's Envisat platform)

metadata

explanatory information about a given data set

METOP

Series of polar orbiting meteorological operational satellites (Metop-A, Metop-B, Metop-C; developed by ESA; operated by EUMETSAT)

microwave

electromagnetic energy at wavelengths ranging from one meter to one millimeter

MIRAS

Microwave Imaging Radiometer using Aperture Synthesis aboard SMOS satellite (soil moisture and ocean salinity)

MOBY

Marine Optical BuoY

MODIS

Moderate Resolution Imaging Spectroradiometer

MODIS/Aqua

MODerate resolution Imaging Spectroradiometer aboard the Aqua satellite (NASA)



N

nadir

When target scene is directly below the satellite (lowest viewing angle)

NASA

National Aeronautics and Space Administration

NCEI

National Centers for Environmental Information (NOAA/NESDIS)

NCEP

National Center for Environmental Predictions (NOAA/NWS)

near real-time

In the satellite remote sensing context, refers to very low data latencies (e.g., data product is available as soon as possible after the remote observation)

NESDIS

National Environmental Satellite, Data, and Information Service (NOAA)

NetCDF

Network Common Data Form

NIR

Near Infrared

NLSST

Non-Linear Sea Surface Temperature

nLw

normalized water-leaving radiance

NMFS

National Marine Fisheries Service (NOAA)

NOAA

National Oceanic and Atmospheric Administration (US Department of Commerce)

node

Point of connection; information about the NOAA CoastWatch Nodes can be found at here

NOS

National Ocean Service (NOAA)

NPOESS

National Polar-orbiting Operational Environmental Satellite System (NOAA)

NPP

National Polar-orbiting Operational Environmental Satellite System Preparatory Project (satellite renamed to Suomi-NPP)

NRC

National Research Council

NRT

Near Real Time



o

OAR

Office of Oceanic and Atmospheric Research (NOAA)

OC

Ocean Color

OLCI

Ocean and Land Color Instrument (aboard Sentinel-3; Copernicus Program)

orbit

The path of a body in space, generally under the influence of gravity.

OSPO

Office of Satellite and Product Operations

out-of-plane maneuver

Operation implementing, by activation of thrusters, a change of the orbital velocity of a satellite in the direction normal to the orbital plane (and consequently a change of the inclination of the orbit). These maneuvers are used to compensate for the orbital perturbations caused by the sun and moon gravity (leading to a change of the orbital inclination). For LEO satellites, as the rate of drift of the mean local solar time of the orbit is linked with the orbital inclination, these maneuver can also be used to implement a change of that rate.



P

payload

The carrying capacity of a spacecraft, including cargo, scientific instruments or fuel.

perigee

The point in the orbit of the moon or a satellite at which it is nearest to the earth

pixel

Datum unit in a grid

platform

Identification of an individual satellite which may carry several instruments or sensors

POES

NOAA’s Polar Operational Environmental Satellites

PolarWatch

A NOAA data portal specializing in ocean and ice remote sensing satellite data and images in mapped projections useful to high latitude regions (Arctic and Antarctic): see: polarwatch.noaa.gov

Poseidon-3B

Radar altimeter onboard Jason-3



Q

QA

Quality Assurance

QC

Quality Control



R

radar

Using radio waves to detect (and characterize) a target object

RADARSAT-2

Radar satellite mission operated in a partnership between a commercial company and the Canadian Space Agency

radiance

Measure of electromagnetic energy (e.g., light or heat energy)

radiation

Electromagnetic energy in the form of waves

radiometer

Instrument that measures radiance

RAN

Abbreviation for systematic reanalysis or reprocessing of satellite data products, in this context

raster

Data in rows and columns

RGB

Red Green Blue

RMS

Root Mean Square



S

S-NPP

Suomi-NPP

SAR

Synthetic Aperture Radar, a remote sensing technique measures surface variability ("roughness")

Scatterometer

Radar systems that infer wind speed by measuring the backscattering cross section. Scatterometers can measure the received power of surface backscattering reflected from the surface of objects.

semi-major-axis

The radius of an orbit at its widest point

Sensor

The "business" part of an instrument that makes the observation

Sentinel

The long term multi-satellite mission for remotely sensed Earth observations in the European Copernicus program. Satellites are named by number and letter (e.g., Sentinel-1B, which primarily makes SAR observations and Sentinel-3A, which has instruments for ocean color, sea surface temperature and ocean altimetry)

SEVIRI

Spinning Enhanced Visible and Infrared Imager onboard ESA’s Meteosat Second Generation (MSG) satellite mission

SLSTR

Sea and Land Surface Temperature Radiometer onboard Sentinel-3 of the EU Copernicus mission

SMOS

Soil Moisture and Ocean Salinity, an ESA satellite mission

Soil Moisture

Water contained in the upper part of the soil mantle.

sounder

Instrument that makes profile or "vertical" observations (e.g., of the atmosphere)

sounders

Instruments that acquire multispectral measurements from which vertical profiles of atmospheric temperature and humidity can be derived to produce particular measurements of depth of water below an instrument (at the surface or at some moored depth), which is computed from the travel time of the acoustic pulse emitted by this sounder.

sounding

Observation in profile (e.g., of a column of atmosphere)

spectrometer

Instrument that make observations across a range of wavelengths

spectrum, spectra, spectral

Spectrum is a set of observations across a range of wavelengths, spectra is plural of spectrum, spectral is adjective form

Spin-stabilized

The method of stabilizing a satellite by means of spin.

SQUAM

NOAA/STAR Sea Surface Temperature Quality Monitor

SRAL

Synthetic Aperture Radar Altimeter onboard Sentinel-3 of the EU Copernicus mission

SSES

Single Senor Error Statistic used by GHRSST

SSM/I

Special Sensor Microwave/Imager onboard the DMSP

SSS

Sea Surface Salinity

SST

Sea Surface Temperature

STAR

Center for Satellite Applications and Research

stratosphere

Layer of atmosphere above the troposphere. The troposphere is closest to Earth

straylight

Extra rays of light hitting SEVIRI's optical path and degrading images.

sun-synchronous

In a sun-synchronous orbit, though, the satellite passes over the same part of the Earth at roughly the same local time each day.

swath

The path width of remote sensing instrument observation



T

telemetry

Remote observation

THREDDS

Thematic Real-time Environmental Distributed Data Services

three-axis stabilized

Satellite platform type. Involves the use of three gyroscopes - one for each axis - to keep satellites correctly oriented in space.

TIFF

Tagged Image File Format

TIROS

Television Infrared Observation Satellite (NASA), first experimental satellite for Earth/weather observations

TOA

Top of atmosphere

top-of-atmosphere

Observation from satellite instrument at the point of the instrument, no adjustments have been made to remove signals contributed by constituents not of primary interest

topography

The shape of the ocean and land. It is used in the context of Jason-2 service.

troposphere

Layer of atmosphere closest to Earth



U

ultraviolet

Electromagnetic energy at ~10 nm to 400 nm wavelengths (shorter than the visible spectrum which is about 400 nm to 700 nm)

upwelling

Dynamic property of ocean physics whereby relatively warm surface waters are forced away allowing deeper ocean water (usually relatively colder and more nutrient-rich) to fill in or replace the disturbed surface water

USEPA

US Environmental Protection Agency

USGS

US Geological Survey

UTC

Universal Time Constant (equivalent to Greenwich Mean Time)

UV

Ultraviolet



V

validation

In this context, refers to comparing satellite observations against another earth observation (e.g., in situ or another satellite) to evaluate the performance of a sensor/instrument

VIIRS

Visible Infrared Imaging Radiometer Suite

VIS

Electromagnetic energy at visible (to human eyes) wavelengths (about 400 nm to 700 nm)

VIS/IR

Visible/Infrared



W

WGS84

World Geodetic System 1984, the reference coordinate system for the Global Positioning System (GPS)

WOCE

World Ocean Circulation Experiment, long term program/dataset of physical oceanographic measurements





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