Full catalog/MERIS_L2_FRS_IOP
MERIS_L2_FRS_IOP·v2022.0·dataset

What's in coastal water from its color (MERIS, full res)

ENVISAT MERIS Level-2 Regional Full Resolution, Full Swath (FRS) Inherent Optical Properties (IOP) Data, version 2022.0
ocean NASA OB_CLOUD Level 2 netCDF-4
In plain English

What it measures. Per-pixel properties of coastal seawater that describe how the water and its contents absorb and scatter light, including signals from phytoplankton and dissolved organic matter, with uncertainty estimates.

How it's made. Retrieved from the color of the water as seen by the MERIS instrument on Europe's ENVISAT satellite, run through an optical model to separate out the different ingredients in the water.

How & where you'd use it. Supports judging water clarity, classifying water types, and biogeochemistry studies, and allows more reliable comparisons between different sensors than basic color products.

What's measured

Oceans › Ocean Optics › AbsorptionOceans › Ocean Optics › ScatteringOceans › Ocean Optics › GelbstoffBiosphere › Ecosystems › Aquatic Ecosystems › Plankton › Phytoplankton

Coverage & cadence

  • Time span2002-03-21 → 2012-05-09
  • Measured byENVISAT (MERIS)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusCOMPLETE

What you can do with it

  • Watch sea-surface temperature and marine heatwaves
  • Spot algal blooms and ocean-colour shifts
  • Support fisheries and coastal monitoring
Official description

The Inherent Optical Properties (IOP) suite provides per-pixel inherent optical properties - quantities that describe how seawater and its constituents absorb and scatter light, independent of illumination or viewing geometry. IOPs are retrieved from spectral Remote Sensing Reflectance (Rrs) using the default configuration of the Generalized Inherent Optical Properties (GIOP) model framework. These products support water-type classification, water-clarity assessment, biogeochemical studies, and forward/adjoint radiative-transfer applications, and they enable more robust cross-sensor comparisons than purely apparent (AOP) products. Geophysical variables in this suite include: - a – Total absorption coefficient (sum of pure water + phytoplankton + CDOM/detritus, m⁻¹) - bb – Total backscattering coefficient (m⁻¹) - l2_flags – Level-2 processing flags (bitmask; see per-variable attributes for flag_masks and flag_meanings) - aph_443 – Phytoplankton absorption coefficient at 443 nm (m⁻¹) - aph_unc_443 – Uncertainty in absorption due to phytoplankton at 443 nm (m⁻¹) - adg_443 – Combined CDOM + non-algal detritus absorption coefficient at 443nm; accompanied by adg_s (spectral slope, units nm⁻¹ - adg_unc_443 – Uncertainty in absorption due to gelbstoff and detrital material at 443 nm (m⁻¹ - bbp_443 – Particulate backscattering coefficient at 443nm (m⁻¹); include bbp_s (power-law slope, unitless) describing spectral shap - bbp_unc_443 – Uncertainty in particulate backscattering at 443 nm (m⁻¹ - rrsdiff – Fractional mean Rrs difference.

Get the data

meris_l2_frs_iop_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MERIS_L2_FRS_IOP",
    version="2022.0",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from OB_CLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.