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Full catalog/MERGED_S3_OLCI_L3m_CYAN
MERGED_S3_OLCI_L3m_CYAN·v6.0·dataset

Where toxic algae bloom in water (Sentinel-3A+3B combined)

Merged Sentinel-3A and Sentinel-3B OLCI Regional Mapped Cyanobacteria Index (CI) Data, version 6.0
biosphere NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. Maps showing where cyanobacteria, the blue-green algae behind many toxic blooms, are present in U.S. lakes and reservoirs (covering the lower 48 states and Alaska). The main value is an index filtered to flag waters dominated by cyanobacteria.

How it's made. Built by combining ocean-color observations from the two Sentinel-3 satellites (3A and 3B) into a single mapped product designed for quick use.

How & where you'd use it. Water-quality managers and researchers use it to spot and track harmful freshwater algae blooms that can threaten drinking water and recreation.

What's measured

BIOLOGICAL CLASSIFICATION › BACTERIA/ARCHAEA › CYANOBACTERIA (BLUE-GREEN ALGAE)OCEANS › WATER QUALITY › ALGAL BLOOMS › HARMFUL ALGAL BLOOM (HABs)OCEANS › WATER QUALITY › ALGAL BLOOMSTERRESTRIAL HYDROSPHERE › WATER QUALITY/WATER CHEMISTRY › WATER CHARACTERISTICS › WATER COLOREARTH SCIENCE SERVICES › ENVIRONMENTAL ADVISORIES › HYDROLOGICAL ADVISORIES › WATER QUALITYTERRESTRIAL HYDROSPHERE › SURFACE WATER

Coverage & cadence

  • Time span2016-04-25 → ongoing
  • Measured bySentinel-3A (OLCI) · Sentinel-3B
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

What you can do with it

  • Map vegetation, forests and biomass
  • Monitor ecosystem productivity and carbon
  • Support habitat and biodiversity studies
Official description

CyAN CI delivers the Cyanobacteria Index for contiguous U.S. (CONUS) and Alaska. The standard product is CI_cyano, which is filtered for cyanobacteria dominated waters only. Products are designed for fast ingest by water-quality managers and researchers monitoring freshwater HABs. The algorithm and processing details are documented in the official release notes. Geophysical variables in this suite include: - band1 – Cyanobacteria Index (DN-encoded) (digital number, unitless)

Get the data

merged_s3_olci_l3m_cyan_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MERGED_S3_OLCI_L3m_CYAN",
    version="6.0",
    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.