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Full catalog/MODISA_L3m_RRS
MODISA_L3m_RRS·v2022.0·dataset

How the ocean reflects sunlight, world map (Aqua MODIS)

Aqua MODIS Level-3 Global Mapped Remote-Sensing Reflectance (RRS) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. A world map of how the ocean reflects sunlight at different wavelengths, basically the ratio of light leaving the water to light coming in just above the surface, given color by color.

How it's made. Built from the MODIS instrument on NASA's Aqua satellite and gridded into a global map; it is the foundational measurement from which other ocean products are calculated.

How & where you'd use it. This is the raw building block used to derive chlorophyll, water clarity, and water-quality products, and to develop and test ocean algorithms. Most people use it through those higher-level products rather than directly.

What's measured

Oceans › Ocean Optics › Reflectance

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 Remote Sensing Reflectance (RRS) suite provides the remote sensing reflectance at wavelength λ (nm)—the ratio of water-leaving radiance to downwelling irradiance just above the surface (units sr⁻¹). Variables are named by their band center (e.g., Rrs_412, Rrs_443). Rrs_λ is the foundational observable used to retrieve products such as chlor_a, Kd_490, IOPs, and to support algorithm development, validation, water-quality, and ecosystem applications. Users should review per-file quality flags (e.g., land, cloud, sun glint, high aerosol) and mission documentation—especially in optically complex coastal/inland waters. Geophysical variables in this suite include: - Rrs — Remote sensing reflectance (sr⁻¹)

Get the data

modisa_l3m_rrs_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MODISA_L3m_RRS",
    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.