Data Sources

Chlorofishy's maps are built from data from eight satellites carrying four kinds of sensors (VIIRS on three platforms, MODIS Aqua, OLCI on two, AMSR2), plus NOAA weather buoys, all public data from NASA and NOAA. Nothing is modeled without saying so, and every reading carries its own capture time, satellite, and native resolution.

Sensors and satellites

Sea surface temperature (SST) and chlorophyll-a concentration each come from several independent sensors, so a gap or a bad reading in one doesn't take down the whole map.

Sea surface temperature

• VIIRS aboard Suomi-NPP, NOAA-20, and NOAA-21: individual satellite passes, ~2km native resolution, typically a few hours old.
• MODIS aboard Aqua: individual satellite passes, ~1km native resolution, typically a few hours old.
• AMSR2 aboard GCOM-W: passive microwave, ~25km native resolution, coarser than the optical sensors above but able to see through cloud cover where they can't.

Chlorophyll-a concentration

• VIIRS aboard Suomi-NPP, NOAA-20, and NOAA-21: individual satellite passes, ~750m native resolution, daytime only, typically a few hours old.
• MODIS aboard Aqua: individual satellite passes, ~1km native resolution, daytime only.
• OLCI aboard Sentinel-3A and Sentinel-3B: daily chlorophyll composite, ~8km effective resolution, typically a day or two old.

What the daily composites are built from

The composite you see by default on each layer is a single blended picture of the entire ocean, built once a day, with cloud gaps filled by combining multiple sensors:

• SST composite: GHRSST MUR L4, NASA's Multi-scale Ultra-high Resolution analysis, 1km resolution, global coverage. Publishes on a measured schedule of roughly two days after the observation date, about 34 hours after the previous day's data would otherwise have appeared.
• Chlorophyll composite: a VIIRS Level-3 daily mapped product from NASA's Ocean Biology processing group, 4km resolution, global coverage, measured at roughly 12 to 14 hours of latency in normal conditions (occasionally longer while NASA's own catalog catches up).

A composite is a gap-filled analysis product, not a raw observation. It is labeled that way everywhere it appears on the map, per our data integrity rules. See how to use Chlorofishy for how to read the difference between a pass and a composite on the map.

A separate rolling SST mosaic, built only from real overnight satellite passes on a roughly 2km grid over a 36-hour window, is not a modeled composite. It's a live stitch of actual observations, refreshed alongside the regular pipeline.

How often the pipeline checks for new data

The pipeline checks every data source for new satellite passes every 10 minutes, around the clock. Buoy observations refresh every 5 minutes. A daily retention sweep runs once a day.

Retention windows

Tile imagery (the colored map layers) is kept for 10 days after capture, then removed; the underlying observation record is kept for 90 days for provenance even after its tiles are gone. Buoy observations follow the same 90-day window. Our storage provider also carries a 14-day backstop expiry policy on tile storage, intended as a safety net behind the 10-day sweep, not a separate retention rule.

Buoys

Weather buoy readings come from NOAA's National Data Buoy Center (NDBC), real in-water measurements, not satellite-derived estimates. Water temperature, wind, and wave conditions refresh every 5 minutes, with up to 7 days of history available per station.

What this data is not for

Chlorofishy is for informational purposes only. Do not rely on this data for navigation, safety, or any purpose where inaccurate data could cause harm. Satellite and buoy data can't detect every localized hazard, and cloud-filled composites are modeled estimates, not direct observations. Always use official charts and follow maritime safety protocols. Full terms are in our Terms of Service.

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