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NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) platform measures the distribution of phytoplankton, a key indicator of ocean health. 

Type

Earth Observation Satellite

Data Center

OB.DAAC

Launch

February 8, 2024

Objective

Study the health of Earth's climate and ocean
ProductDescription/UseAvailability/LatencyStatus
Calibrated Radiometry and Polarimetry
Spectral top-of-atmosphere radiances from OCISpectral radiance observed at the top of the atmosphere.

Level-1B: daily

Level-1C: daily

Standard Product
Spectral top-of-atmosphere radiances and polarimetry from SPEXoneSpectral radiance and polarimetry observed at the top of the atmosphere, for all sensor viewing angles.

Level-1B: daily

Level-1C: daily

Standard Product
Spectral top-of-atmosphere radiances and polarimetry from HARP2Spectral radiance and polarimetry observed at the top of the atmosphere, for all sensor viewing angles.

Level-1B: daily

Level-1C: daily

Standard Product
Ocean Properties to be Produced by OCI
Spectral remote sensing reflectancesSpectral color of the ocean in the ultraviolet-to-near infrared spectral range. Used as input into algorithms to retrieve information about colored dissolved organic matter, phytoplankton, non-algal particles, and other aquatic constituents. Provided in continuous 2.5-nm steps from 350 to 717.5-nm with a resolution (bandwidth) of 5-nm.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Apparent visible wavelengthAn optical water classification index reported as the weighted harmonic mean of visible-range Rrs wavelengths (400-700 nm).

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Spectral diffuse attenuation coefficientsSpectral diffuse attenuation of downwelling irradiance at multiple wavelengths between 350 and 700 nm. Provides indices of water clarity and light penetration.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Spectral phytoplankton absorption coefficientsSpectral absorption coefficients for total phytoplankton absorption at multiple wavelengths between 350 and 700-nm. Provides information on phytoplankton physiology, abundance, and community composition.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Spectral non-algal particle plus dissolved organic matter absorption coefficientsSpectral absorption coefficients for non-algal particulates and dissolved organic matter at multiple wavelengths between 350 and 700-nm. Provides information on the concentrations of the dissolved component of organic carbon and the detrital (non-algal) component of the particulate assembly.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Spectral chromophoric dissolved organic matter absorption coefficientsSpectral absorption coefficients for dissolved organic matter at multiple wavelengths between 350 and 700-nm. Provides information on the concentration of the dissolved component of organic carbon.TBDTest
Spectral slope coefficients of chromophoric dissolved organic matter absorptionAbsorption spectral slope coefficients of chromophoric dissolved organic matter for multiple wavelength ranges: 275-295, 350-400, 380-600 nm. Provides information on the contribution of land-derived dissolved organic matter, relative contribution of land- versus marine-derived dissolved organic matter, and as a relative measure of solar photobleaching.TBDTest
Spectral non-algal particle matter absorption coefficientsSpectral absorption coefficients for non-algal particulate matter at multiple wavelengths between 350 and 700 nm. Provides information on the concentration of non-phytoplankton particulate components.TBDTest
Spectral particlulate matter absorption coefficientsSpectral absorption coefficients for particulate matter at multiple wavelengths between 350 and 700 nm. Provides information on the concentration of particulate matter in the water column.TBDTest
Spectral particle backscattering coefficientsSpectral backscattering of the light associated with particulate material, at multiple wavelengths between 350-700 nm. Provides an indicator of the concentration of particules in the ocean and a proxy indicator of particulate carbon concentrations.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Fluorescence line heightLight leaving the surface ocean due to the sun induced chlorophyll fluorescence. Provides an indicator of phytoplankton physiology (health?).

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Daily photosynthetically available radiation (PAR)The amount of sunlight that is useful for photosynthesis, defined here as the 400-700 nm spectral range, that reaches the surface of the ocean over a day. As phytoplankton require light to convert inorganic carbon to organic carbon, PAR provides a critical parameter for understanding the oceanic carbon cycle.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Instantaneous photosynthetically available radiation (iPAR)The amount of sunlight that is useful for photosynthesis, defined here as the 400-700 nm spectral range, that reaches the surface of the ocean at the moment of satellite data collection. As phytoplankton require light to convert inorganic carbon to organic carbon, iPAR provides a critical parameter for understanding the oceanic carbon cycle.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Concentration of chlorophyll-aNear surface concentration of the photosynthetic pigment chlorophyll-a. Provides proxies for algal biomass, ecosystem health and function, and eutrophication.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Phytoplankton pigment concentrationsConcentration of specific photosynthetic pigments in the surface ocean. As different phytoplankton taxa contain their own specific pigment suites, these concentrations provide indicators of presence and abundance of specific types of phytoplankton in the ocean (e.g. harmful algal blooms).TBDTest
Net primary production (NPP)Rate of conversion of dissolved carbon dioxide to organic carbon through photosysthesis minus the carbon used for respiration. NPP is an important part of the carbon cycle and these products are used in local models (estimating food avaliable to fish populations) all the way up to global climate and Earth System models (to predict information about the oceans of today and tomorrow).TBDTest
Phytoplankton community compositionDescriptors of the composition of phytoplankton populations. Different approaches describe these populations in different ways, such as by carbon content or biovolume per class (e.g., diatom contributions vs. cyanobacteria contributions), particle size distributions (or fraction of large cells vs. small cells), or targeted identification of a single class (e.g., detection of a harmful cyanobacteria algal bloom).TBDTest
Concentration of particulate organic carbonNear surface concentration of the particulate organic carbon. It is a proxy for all living material (phytoplankton, zooplankton, bacteria) and detritus. It is also a venue through which organic carbon, sequestered through the photosynthesis, is transferred towards higher trophic levels and into the deep ocean.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Concentration of particulate inorganic carbonConcentration of particulate inorganic carbon in the surface of the ocean. Used to track the presence and abundance of calcite containing phytoplankton in the open ocean (coccolithophores).

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Standard Product
Concentration of phytoplankton carbonConcentration of carbon contained in phytoplankton cells. Provides a proxy for phytoplankton biomass that is often used in primary productivity algorithms and biogeochemical and Earth System models.

Level-2: daily

Level-3: daily, 8-day, monthly, annual

Provisional
Concentration of dissolved organic carbonNear surface concentration of dissolved organic carbon. It is exported into coastal waters from land through rivers and groundwater. In the aquatic environment, it is produced or released by all living material (phytoplankton, zooplankton, bacteria) and detritus. It is a source of energy for bacteria and other microbial organisms and is transferred to higher trophic levels. It typically comprises well over 95% of the organic carbon in the ocean.TBDTest
Suspended particulate matterNear surface concentration of particles both living (phytoplankton, zooplankton, bacteria) and non-living (detritus, sediments).TBDTest
Atmospheric Properties to be Produced by OCI
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles, such as dust and haze, at 380, 440, 500, 550, and 675 nm (and potentially additional wavelengths) over land and oceans. Provides information on the concentration of aerosols in a vertical column of atmosphere.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Aerosol fine mode fraction (over ocean)Fraction of visible aerosol optical depth from fine mode aerosols over oceans at 550 nm.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Cloud maskProvides information on whether or not a given pixel is covered by cloud. This is an input to many downstream algorithms, as most process either only cloudy or only cloud-free scenes, and is also useful for climate research.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Cloud phaseProvides information on whether a given cloudy pixel is composed of liquid-phase or ice-phase clouds. Used as an input to downstream processing to inform optical model choices, as well as for climate research.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Cloud top pressure of opaque cloudsAtmospheric pressure at the height of the cloud top. Useful for climate research and in L1c reaggregation.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Optical thickness of liquid and ice cloudsMeasurement of extinction of the solar beam due to clouds in the mid-visible wavelength. Used for climate studies.

Level-2: daily

Level-3: daily, 8-day, monthly

Standard Product
Effective radius of liquid and ice cloudsRatio of the third to second moments of the cloud droplet size distribution, as an indicator of cloud particle size. Used for climate studies.

Level-2: daily

Level-3: daily, 8-day, month

Standard Product
Water path of liquid and ice cloudsMass of (liquid or ice) water in clouds in the vertical column. Used for climate studies.

Level-2: daily

Level-3:  daily, 8-day, monthly

Standard Product
Shortwave radiation effectReflected solar flux (spectral and directional integral of reflected sunlight).

Level-2: daily

Level-3: daily, monthly

Standard Product
Land Data Products to be Produced by OCI
Surface reflectanceEffective reflectance of the Earth's surface as observed by OCI. Used as an input to downstream land data products.TBDTest
BRDF/albedo and model parametersDescribes the spectral and directional dependence of surface reflectance.TBDTest
Normalized difference vegetation index (NDVI)Empirical metric related to vegetation abundance and health, corrected for atmospheric scattering and absorption.TBDTest
Enhanced vegetation index (EVI)Empirical metric related to vegetation abundance and health, similar to NDVI, with additional resistance to atmospheric effects and sensitivity in densely vegetated regions.TBDTest
Photochemical reflectance index (PRI)Hyperspectral vegetation index designed to capture subtle shifts in carotenoids and provides information on stress in plantsTBDTest
Aerosol and Ocean Properties from HARP2
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles. Provides information on the concentration of aerosols in a vertical column of atmosphere. May be represented separately for different aerosol size/type modes.TBDTest
Aerosol size distributionMultiple parameters describing the distribution of aerosol sizes. May include multiple size modes or bins.TBDTest
Aerosol complex refractive indexReal and imaginary component of refractive index for each aerosol mode. This defines aerosol extinction, scattering and absorption.TBDTest
Aerosol layer heightParameterization of aerosol vertical distribution.TBDTest
Aerosol shape, fraction sphericalFraction of aerosols that are treated as spheres versus other shapes, such as spheroids.TBDTest
Spectral remote sensing reflectancesSpectral color of the ocean in the visible spectral range. Used to evaluate performance of atmospheric correction based on aerosol properties retrieved from polarimeters, faciliate synergy with other instruments.TBDTest
Aerosol single scattering albedoRatio of aerosol scattering to extinction.TBDTest
Ocean surface roughnessSurface roughness defines the directionality of the solar specular reflectance (sunglint), often parameterized by wind speed and direction.TBDTest
Ocean body propertiesIn water optical properties that define the water leaving radiance. Parameterization schemes may be simple or complex, the validity of which depend on ocean conditions.TBDTest
Aerosol and Land Surface Properties from HARP2
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles. Provides information on the concentration of aerosols in a vertical column of atmosphere. May be represented separately for different aerosol size/type modes.TBDTest
Aerosol number concentrationNumber of aerosols present within a defined volume or area.TBDTest
Aerosol size distributionMultiple parameters describing the distribution of aerosol sizes. May include multiple size modes or bins.TBDTest
Aerosol complex refractive indexReal and imaginary component of refractive index for each aerosol mode. This defines aerosol extinction, scattering and absorption.TBDTest
Aerosol layer heightParameterization of aerosol vertical distribution.TBDTest
Aerosol shape, fraction sphericalFraction of aerosols that are treated as spheres versus other shapes, such as spheroids.TBDTest
Aerosol single scattering albedoRatio of aerosol scattering to extinction.TBDTest
Spectrally resolved land surface Bidirectional Reflectance Distribution Function (BRDF)Defines the reflectance as a function of illumination and observation characteristics. Often represented as a modal sum of angular distribution kernels.TBDTest
Spectrally resolved land surface Bidirectional Polarized Distribution Function (BPDF)Defines the surface polarization as a function of illumination and observation characteristics.TBDTest
Cloud Properties from HARP2
Cloud detectionCloud identification, either as binary flag, percentage or other metric.TBDTest
Cloud physical thicknessDistance between cloud base and cloud top.TBDTest
Cloud top heightAltitude of cloud top.TBDTest
Cloud top phaseDetermination of liquid or ice phase cloud.TBDTest
Cloud optical depthSynonymous with cloud optical thickness.TBDTest
Liquid cloud droplet effective radius and effective varianceA microphysical property describing droplet size distribution and distribution width.TBDTest
Ice particle shape and asymmetry parameterParameterization of shape is relevant for radiative transfer modeling.TBDTest
Liquid water pathCan be derived from measures of optical depth and droplet size distribution.TBDTest
3D cloud field3D reconstruction of cloud vertical and horizontal distribution using multi-angle polarimetry.TBDTest
Ocean Surface Properties from HARP2
Aerosol optical depth in the near infraredByproduct of the primary algorithm.TBDTest
Ocean surface refractive indexIndication of non-seawater substances on the ocean surface, such as oil.TBDTest
Aerosol and Ocean Properties from SPEXone
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles. Provides information on the concentration of aerosols in a vertical column of atmosphere. May be represented separately for different aerosol size/type modes.TBDTest
Aerosol size distributionMultiple parameters describing the distribution of aerosol sizes. May include multiple size modes or bins.TBDTest
Aerosol complex refractive indexReal and imaginary component of refractive index for each aerosol mode. This defines aerosol extinction, scattering and absorption.TBDTest
Aerosol layer heightParameterization of aerosol vertical distribution.TBDTest
Aerosol shape, fraction sphericalFraction of aerosols that are treated as spheres versus other shapes, such as spheroids.TBDTest
Aerosol single scattering albedoRatio of aerosol scattering to extinction.TBDTest
Ocean surface roughnessSurface roughness defines the directionality of the solar specular reflectance (sunglint), often parameterized by wind speed and direction.TBDTest
Ocean body propertiesIn water optical properties that define the water leaving radiance. Parameterization schemes may be simple or complex, the validity of which depend on ocean conditions.TBDTest
Aerosol and Land Surface Properties from SPEXone
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles. Provides information on the concentration of aerosols in a vertical column of atmosphere. May be represented separately for different aerosol size/type modes.TBDTest
Aerosol number concentrationNumber of aerosols present within a defined volume or area.TBDTest
Aerosol size distributionMultiple parameters describing the distribution of aerosol sizes. May include multiple size modes or bins.TBDTest
Aerosol complex refractive indexReal and imaginary component of refractive index for each aerosol mode. This defines aerosol extinction, scattering and absorption.TBDTest
Aerosol layer heightParameterization of aerosol vertical distribution.TBDTest
Aerosol shape, fraction sphericalFraction of aerosols that are treated as spheres versus other shapes, such as spheroids.TBDTest
Aerosol single scattering albedoRatio of aerosol scattering to extinction.TBDTest
Spectrally resolved land surface Bidirectional Reflectance Distribution Function (BRDF)Defines the reflectance as a function of illumination and observation characteristics. Often represented as a modal sum of angular distribution kernels.TBDTest
Spectrally resolved land surface Bidirectional Polarized Distribution Function (BPDF)Defines the surface polarization as a function of illumination and observation characteristics.TBDTest
Aerosol and Ocean Properties from OCI + HARP2 + SPEXone
Spectral aerosol optical depthSpectral measurement of the extinction of the solar beam caused by atmospheric aerosol particles. Provides information on the concentration of aerosols in a vertical column of atmosphere. May be represented separately for different aerosol size/type modes.TBDTest
Aerosol size distributionMultiple parameters describing the distribution of aerosol sizes. May include multiple size modes or bins.TBDTest
Aerosol complex refractive indexReal and imaginary component of refractive index for each aerosol mode. This defines aerosol extinction, scattering and absorption.TBDTest
Aerosol layer heightParameterization of aerosol vertical distribution.TBDTest
Aerosol shape, fraction sphericalFraction of aerosols that are treated as spheres versus other shapes, such as spheroids.TBDTest
Aerosol scattering phase matrixDefined by above parameters, this describes the angular distribution of scattering and polarization.TBDTest
Aerosol single scattering albedoRatio of aerosol scattering to extinction.TBDTest
Spectral remote sensing reflectancesSpectral color of the ocean in the visible spectral range. Used to evaluate performance of atmospheric correction based on aerosol properties retrieved from polarimeters, faciliate synergy with other instrumentsTBDTest
Ocean surface roughnessSurface roughness defines the directionality of the solar specular reflectance (sunglint), often parameterized by wind speed and direction.TBDTest
Ocean body propertiesIn water optical properties that define the water leaving radiance. Parameterization schemes may be simple or complex, the validity of which depend on ocean conditions.TBDTest
Thin cloud contaminationSome algorithms may detect the presence of optically thin clouds (usually cirrus) that would otherwise adversely affect the retrieval of other parameters.TBDTest

PACE carries three instruments:

  • Ocean Color Instrument (OCI): Primary instrument; hyperspectral radiometer
  • Hyper Angular Research Polarimeter (HARP2): multi-angle polarimeter
  • Spectro-polarimeter for Planetary Exploration (SPEXone): multi-angle polarimeter
ParameterOCIHARP2SPEXone
Spectral Range/Bandwidth342.5 - 887.5 at 5 nm steps440, 550, 670 (10 nm), 870 (40 nm)385 - 770 nm at 2 - 4 nm steps
Shortwave Infrared (OCI)/Polarized Bands (HARP2, SPEXone)Seven bands centered on 940, 1038, 1250, 1378, 1615, 2130, 2260 nmAllSame range in 15 to 45 nm steps
Number of Viewing AnglesFore-aft tilt ± 20° to avoid sunglint10 for 440, 550, 870 nm; 60 to 670 nm (spaced over 114°Five (-57°, -20°, 0°, 20°, 57°)
Coverage (Swath Width)± 56.5° (2663 km at 20° tilt)± 47° (1556 km at nadir)± 4.5° (106 km at nadir)
Global Coverage1-2 days2 days30+ days
Ground Pixel1 km at nadir3 km2.5 km
Institution(s)NASA's Goddard Space Flight Center in Greenbelt, MarylandUniversity of Maryland - Earth and Space InstituteSRON Netherlands Institute for Space Research, Airbus Defense and Space Netherlands, TINO 

The OCI will have a maximum 2500 km swath width, a resolution of 1 km and a 5 nm spectral resolution. It will be capable of wavelength measurements from ultraviolet (340 nm) to near-infrared (890 nm)

SPEXone is a spectro-polarimeter that provides continuous wavelengths coverage in the range 385-770 nm. Spectral resolution is 2-5 nm for radiance and 10-40 nm for DoLP. It observes a ground pixel under 5 viewing angles (0°, ±22° and ±58° on ground), where the ±22° viewports will be used for cross calibration with OCI.

HARP2 will combine data from multiple along track viewing angles (up to 60), four spectral bands in the visible and near infrared ranges, and three angles of linear polarization to measure the microphysical properties of the atmospheric particles including their size distribution, amount, refractive indices, and particle shape.

All science data files produced from PACE will follow the standard naming convention of NASA's Ocean Biology Processing Group (OBPG). The filename leader will be PACE_OCI, PACE_HARP, or PACE_SPEX for OCI, HARP2, and SPEXone, respectively.

OBPG naming convention:

MMMM_IIII_TTT.YYYYMMDDTHHMMSS.LLLL.PPPP.SSSS.pppp.RRRR.NRT.nc

  • MMMM*: variable-length uppercase character string indicating the "mission".
    • e.g. AQUA, PACE, S3A
  • IIII: variable-length uppercase character string indicating the instrument
    • e.g. OCI (PACE Ocean Color Instrument)
  • TTT: (value is absent if not relevant to product) variable-length uppercase character string indicating the data "type"
    • e.g. GAC (SeaWiFS Global Area Coverage); EFR (OLCI Full Resolution)
  • YYYYMMDDTHHMMSS: ISO8601 time format, where YYYY is the 4-digit year, MM is the two-digit month, DD is the two-digit day, T indicates the time follows this character, HHMMSS are the two-digit hour, minutes, and seconds, respectively.
  • LLLL: variable-length character string indicating the level.
    • e.g. L1B, L2, L3m
  • PPPP: period indicator for L3
    • e.g. DAY, MO, YR, R32
  • SSSS: suite identifier
    • e.g. RRS, CHL
  • pppp: product identifier
    • e.g. Rrs_412, chlor_a
  • RRRR**: resolution
    • e.g. 4km
  • NRT: (value is absent if not relevant to product) Near Real-Time identifier

* The mission identifier could be a reasonably shortened representation, e.g. Sentinel-3A = S3A
** The resolution element includes the units, e.g. 4km, 1deg

All PACE data available through NASA are fully and openly available without restriction.

For data distributed by NASA’s Ocean Biology Distributed Active Archive Center (OB.DAAC), use the reference notation of: Author, Release Date, Dataset Title, Publisher, doi reference, and date accessed.

Example:

NASA Ocean Biology Processing Group. (2018). Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Level-2 Cloud Phase (daily), NASA Ocean Biology Distributed Active Archive Center. doi:XX.XXXX/XXXXX. Accessed on Month/day/year.

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