Full catalog/MODISA_L3b_IOP
MODISA_L3b_IOP·v2022.0·dataset

How ocean water absorbs and scatters light (Aqua)

Aqua MODIS Level-3 Global Binned Inherent Optical Properties (IOP) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. How seawater and the stuff floating in it absorb and scatter light, independent of sun angle or viewing direction. It includes how strongly the water absorbs light and how much it scatters light back, broken out by contributors like phytoplankton and dissolved organic matter.

How it's made. Retrieved from MODIS ocean-color measurements on NASA's Aqua satellite, run through a standard optical model and binned into a global gridded product.

How & where you'd use it. Supports classifying water types, judging water clarity, studying ocean biology and chemistry, and comparing results consistently across different satellites.

What's measured

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

Coverage & cadence

  • Time span2002-07-04 → ongoing
  • Measured byAqua (MODIS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

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) - 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 shape. - bbp_unc_443 — Uncertainty in particulate backscattering at 443 nm (m⁻¹). - rrsdiff — Fractional mean Rrs difference.

Get the data

modisa_l3b_iop_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MODISA_L3b_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.