This parameter describes several different types of absorption:
Absorbed radiation by phytoplankton (ARP)
This parameter is critical for calculation of
fluorescence efficiency, and determining photosynthetic rate of growth of phytoplankton
and primary ocean production. Downwelling irradiance is
needed as an input to the chlorophyll a algorithm and it is
used to convert the normalized water-leaving radiance
values into remote-sensing reflectance values.
Gelbstoff absorption coefficient
It is operationally defined as the absorption coefficient
of the material that can fit through a 0.2 micron filter. It is also
known as yellow substance or colored dissolved organic material (CDOM) absorption.
Chlorophyll a absorption
The chlorophyll a absorption coefficient is that part of the absorption coefficient
attributable to chlorophyll a.
Total absorption
This includes includes absorption due to water, phytoplankton, detritus and gelbstoff.
This level 2 data collection contains four products describing ambient
aerosol optical thickness and size distribution over the ocean and the moist
parts of the continents. All products have 10-km spatial resolution at
nadir. The products are:
daytime aerosol optical thickness over the ocean;
daytime aerosol ratio of large/small modes over the ocean;
daytime aerosol mean particle size over the ocean; and
daytime aerosol optical thickness over land.
The file size for the product is 10 MB and the file transfer rate
is 144/day.
Data other than instrument data required to perform an instrument's data processing.
They include orbit data, attitude data, time information, spacecraft engineering data, calibration
data, data quality information, and data from other instruments.
Aqua (formerly PM-1) is the second of the EOSDIS spacecraft. Launch will be no earlier than July 12, 2001. Aqua carries 6 instruments: AIRS (Atmospheric Infrared Sounder), AMSU (Advanced Microwave Sounding Unit), AMSR-E (Advanced Microwave Scanning Radiometer-EOS), CERES (Clouds and the Earth's Radiant Energy System, HSB (Humidity Sounder for Brazil) and MODIS (Moderate Resolution Imaging Spectroradiometer). For more info, please see the Aqua website.
The relative position of an object within the field of view of an antenna in the plane
intersecting the moving radar's line of flight. The term commonly is used to indicate linear
distance or image scale in the along-track direction.
The total dry organic matter or stored energy content of living organisms that is present
at a specific time in a defined unit (community, ecosystem, crop, etc.) of the Earth's surface.
This is the estimated calcite concentration due to coccoliths.
Coccolithophores are small marine phytoplankton which form
external calcium carbonate scales, called coccoliths, having diameters of a few
microns and a thickness of 250 to 750 nm.
This Level 1A data set contains counts for all 36 MODIS channels,
all spatial resolutions, all time tags (converted), all detector views (Earth,
solar diffuser, SRCA, black body, and space view), along with
raw instrument engineering and spacecraft ancillary data. See below for info
on specific resolutions.
This Level 1B data collection contains calibrated and geolocated
radiances at-aperture for bands 1 and 2 generated from MODIS Level 1A
sensor counts (MOD02QKM). For day mode the file size is 273 MB and for
night mode the file size is 21 MB. The file transfer rate is 288/day.
This Level 1B data collection contains calibrated and geolocated
radiances at-aperture for bands 3 through 7 generated from MODIS Level 1A
sensor counts. Includes the 250 m bands calibrated data aggregated to
500 m resolution (MOD02HKM). For day mode the file size is 262 MB and for
night mode the file size is 21 MB. The file transfer rate is 288/day.
This Level 1B data collection contains calibrated and geolocated
radiances at-aperture for 36 bands generated from MODIS Level 1A
sensor counts. Includes the 250 m and 500 m bands calibrated data
aggregated to 1 km resolution (MOD021KM). For day mode the file size is
319 MB and for night mode the file size is 128 MB. The file transfer rate
is 288/day.
This product contains ocean clorophyll-a pigment concentration
for Case 1 and Case 2 waters at 1km resolution. It is produced daily at Level
2 and 3 and weekly at Level 3.
This is a daily, global Level 2 product generated at the 1 km and 250 m
(at nadir) spatial resolution. The algorithm employs a series of visible and
infrared threshold and consistency tests to specify confidence levels that
an unobstructed view of the Earth's surface is observed. An indication of
shadows affecting the scene is also provided. The 250 m cloud mask flags are
based on the visible channel data only. Radiometrically accurate radiances
are required, so holes in the Cloud Mask will appear wherever the input
radiances are incomplete or of poor quality.
The footprint coverage of a remote sensing sensor projected on a surface (i.e. A graphical
representation of the coverage of data or a granule located on the Earth.
This Level 3 data collection contains daily gridded averages of
infrared-derived precipitable water vapor, aerosol optical depth, aerosol
size distribution, stability indices, and total ozone burden at 0.5-degree
resolution. The file size is 450 MB and the file transfer rate is 1/day.
A 'data group' is a grouping of ECS data collections by instrument and mission, except in the case of MODIS data, where the grouping is by instrument, mission, and major discipline. For example, MOAA is MODIS Atmosphere data from the Aqua mission and ASTT is ASTER data from the Terra mission.
Data in their original packets, as received from the observer.
Level 0
Raw instrument data at original resolution, time ordered, with duplicate packets
removed.
Level 1A
Reconstructed unprocessed instrument/payload data at
full resolution; any and all communications artifacts
(e.g. synchronization frames, communications headers) removed.
Level 1B
Level 1A data that have been processed to sensor units and radiometrically
corrected and geolocated.
Level 2
Derived geophysical variables at the same resolution
and location as the Level 1 source data.
Level 3
Variables mapped on uniform space-time grid scales,
usually with some completeness and consistency.
Level 4
Model output or results from analyses of lower level
data (i.e., variables derived from multiple measurements).
Date Set is the primary means by which EOSDIS identifies the major emphasis of the content of a data collection. For example: 'cloud top products generated from instrument X or 'all products containing sea surface temperature as skin temp' The term 'data set' in EOSDIS is informal usage for the formal term ESDT or Earth Science Data Type.
This coefficient is also known as K 490. It is defined as the rate at
which the natural log of spectral downwelling irradiance decays with depth.
The units are in inverse meters. It can be a function of wavelength and depth.
It is an apparent optical property, that is a function of the illumination
geometry. The diffuse attenuation coefficient can be approximated to first
order by the sum of the absorption and back-scattering coefficients.
EOSDIS is the Earth Observing System Display and Information System.
At present, EOSDIS manages data from NASA's past and current Earth science
research satellites and field measurement programs, providing data archiving,
distribution, and information management services. During the EOS era that started with the launch of the TRMM satellite in 1997, EOSDIS will command and control satellites and instruments, and will generate useful products from orbital
observations. EOSDIS will also generate data sets made by assimilation of satellite and in situ
observations into global climate models. Several steps are being taken to increase flexibility in
EOSDIS by distributing the responsibility for provision of its various services. In the near-term, the
data assimilation products, the data products from the EOS instruments on TRMM, some of the EOS
Terra (formerly AM-1) instruments, and SAGE III will be generated either at the Principal
Investigators' computing facilities or under their direct control. An adaptive approach will be used
during the EOS Aqua (formerly PM-1) era to determine the best assignment of responsibility for product generation
considering technical advantages, cost and schedule. An experiment is now underway with a set of
competitively selected "Working Prototype Earth Science Information Partners (WP-ESIPs)" to
examine the feasibility of providing data services through a federation of ESIPs. Such a federation
could provide an additional measure of flexibility in distributing the responsibilities during the EOS
CHEM era. For more information, please see the EOSDIS Overview page.
This is the ratio of clear water-leaving radiance at 531 nm to that at 667 nm.
The primary purpose of this parameter is to estimate aerosol iron content over ocean waters.
ESDT stands for Earth Science Data Type and is the primary means by which EOSDIS identifies the major emphasis of the content of a data collection. For example: 'cloud top products generated from instrument X or 'all products containing sea surface temperature as skin temp'.
The gelbstoffe absorption coefficient is that part of the absorption
coefficient attibutable to galbstoffe. It is operationally defined as
the absorption coefficient of the material that can fit through a 0.2 micron filter. It is also known as yellow substance or colored
dissoluted organic material absorption (CDOM).
This geolocation data collection contains geodetic coordinates, ground
elevation, solar and satellite zenith, and azimuth angle estimated from the
spacecraft attitude and orbit, instrument telemetry, and a digital elevation
model for each MODIS 1-km sample. The file size is 58 MB and the file
transfer rate is 288/day.
The smallest aggregation of data which is independently managed (i,e., described, inventoried, retrieved) within DataPool. Note that granules are uniquely identified with ECS by a universal reference (UR) but that what is shown as the identifier in the DataPool WebAccess results screen is only a portion of the granule UR (the granule id) and is unique only to the site where the search was performed. The granule UR can be found in the full metadata of the granule that is returned as part of the results set.
A unique identifier for a granule. 'UR' stands for 'universal reference'. GranuleURs are unique across the EOSDIS Core System distributed archives (DAACs).
All EOSDIS data times are stored in GMT. GMT stands for Greenwich Mean Time which is a reference to the time zone of Greenwich, England. GMT is a 'universal' time zone in that it is the reference on which our modern day time zones are based (other zones reference GMT to establish their local time). In our current time zone system, the day begins at 12:00 Midnight in Greenwich. GMT is also known as Greenwich Meridian Time due to the fact that Greenwich is situated on the Prime Meridian (Zero Degrees Longitude).
A detailed description of a number of data sets and related entities, containing information
suitable for making a determination of the nature of each data set and its potential usefulness
for a specific application.
The elliptical path of a satellite orbit lies in a plane known as the orbital plane. The
orbital plane always goes through the center of the Earth but may be tilted at any angle
relative to the equator. Inclination is the angle between the equatorial plane and the orbital
plane measured counter-clockwise at the ascending node.
The rate at which a collimated beam of light is absorbed by a volume of
sea water. The units are inverse meters. It can be a function of wavelength
and depth. It is an inherent optical property that is independent of the
illumination geometry.
The instantaneous photosynthetically available radiation (PAR)
is the total downwelling flux of photons just below the sea surface. This parameter is critical for
determining photosynthetic rate of growth of phytoplankton and primary ocean production.
Temperature measurement scale used in the scientific community. Zero K represents
absolute zero and corresponds to -459 degrees Fahrenhite or -273 Celsius.
MODIS has 36 channels with spectral range from 0.62 to 14,385 µm.
The spatial resolution of the channels are as follows: 250 m (bands
1-2), 500 m (bands 3-7) and 1 km (bands 8-36). For more details, see
the
MODIS Technical Specifications page.
This Level 3 data collection contains monthly gridded averages of
infrared-derived precipitable water vapor, aerosol optical depth, aerosol
size distribution, stability indices, and total ozone burden at 0.5 degree
resolution. The file size is 500 MB and the file transfer rate is 1/month.
This is calibration sector data from Black Body, Solar Diffuser, Solar Diffuser Stability Monitor, Space View in Raw Counts along with Engineering data in scientific units.
These are parameters that describe the optical
properties of the water or the layer directly above the water.
They include normalized water-leaving radiances, tau aerosol, epsilon, epsilon for clear
water, instantaneous photosynthetically available radiation (PAR), and diffuse attenuation.
A molecule made up of three atoms of oxygen. In the stratosphere, it occurs naturally and
provides a protective layer shielding the Earth from ultraviolet radiation and subsequent
harmful health effects on humans and the environment.
Term derived from "picture element" in a digital representation to indicate the spatial position
of a sample of an image file, which consists of a spatial array of digital numbers.
A two-dimensional ensemble of pixels forms the geometric grid on which an image is built.
This Level 1A data collection contains digitized counts for all 36 MODIS
channels, along with raw instrument engineering and spacecraft ancillary data.
Visible, SWIR and NIR measurements are made during daytime only, whereas TIR
measurements are made continuously.Therefore, files sizes change depending
on the time of day. For day mode the file size is 537 MB while for night
mode the file size is 178 MB. The file transfer rate is 288/day.
This Level 2 and 3 product provides sea surface temperature at 1 km
resolution over the global ocean. In addition, a quality assessment parameter
is included for each pixel. The Level 2 product is produced daily and consists
of global day and night coverage every 24 hours. It is used to generate
the gridded Level 3 products daily and weekly for day and night
conditions. a quality parameter is provided for each dataset.
This is a measure of ocean suspended sediments which is used in the
analysis of complex bio-optical properties of coastal and estuarine
regions/environments and helps to map the extent of terrestrial changes.
Tau aerosol or aerosol optical depth is
dimensionless parameter provided for cloud-free
pixels (with Sun glitter below a threshold) when all valid pixels
are outside a distance threshold from land.
Terra is the flagship in NASA's Earth Observing System. It launched in December 1999 and began collecting science data on February 24,2000. Terra carries five sensors: ASTER, CERES, MISR, MODIS and MOPITT. For more information, see the Terra web site.
The total pigment parameter in Case 1 waters is the sum of
chlorophyll a and phaeopigment concentration. Case 1 waters have optical properties, which are
dominated by chlorophyll and associated covarying detrital
pigments. In contrast, Case 2 waters contain substances
which affect optical properties that may not covary with
chlorophyll such as gelbstoff, suspended sediments,
coccolithophores, detritus and bacteria.
This is the radiance that would exit the ocean in the absence of the
atmosphere if the Sun were at the zenith. This Level 2 and 3 product contains
ocean water-leaving radiances for 7 of the 36 wavelengths/spectral bands
(Band 8 through 14, 412 through 681nm) of MODIS. The Level 2 product is
provided daily at 1km resolution for cloud-free pixels.
This Level 3 data collection contains 8-day gridded averages of
infrared-derived precipitable water vapor, aerosol optical depth, aerosol
size distribution, stability indices, and total ozone burden at 0.5-degree
resolution. The file size is 750 MB and the file transfer rate is 1/week.