VIIRS single-sensor S-NPP and NOAA-20 Anomaly products

Near-real-time (NRT) global daily chlorophyll-a (Chl-a) anomaly products that can be used to detect and identify algae blooms from satellite ocean color measurements such as those from the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) and NOAA-20. Specifically, the production of the two Chl-a anomaly products, one for the Chl-a anomaly in difference and another for the Chl-a anomaly ratio (actually, the proportional difference or relative difference; product is labelled "pdif" in the files) compared to the 61-day Chl-a median value from the previous time period (as a Chl-a reference), has been implemented in the daily global NRT satellite data processing. These two Chl-a anomaly products represent the global ocean and coastal/inland water Chl-a abnormal condition for a given location and can provide more complete characteristics for the daily phytoplankton (or algae) biomass status by comparing to the normal condition. 

    Data Access
    THREDDS
    Sample Filenames

    V2021008_D1_NRT_WW00_chloradiff.nc
    V2021007_D1_NRT_WW00_chlorapdif.nc

    Global map projection of anomalies of chlorophyll-a concentration
    Short Names
    NOAA VIIRS Chlorophyll Anomaly
    Temporal Coverage

    Daily; computed by difference or ratio of a 61 day mean

    Product Families
    Ocean Color
    Measurements
    Chlorophyll-a Anomaly Difference
    Chlorophyll-a Anomaly Ratio
    Processing Levels
    Level 3
    Latency Groups
    24+ hours (Delayed)
    Latency Details

    48 hours

    Spatial Resolution Groups
    2km+
    Spatial Resolution Details

    2km (2.3163 km or 0.02¬į)

    Data Providers
    NOAA
    Spatial Coverage

    Global

    Description

    180W - 180E
    90N - 90S

    MSL12

    Description

    Multi-Sensor Level-1 to Level-2 (MSL12) Ocean Color Data Processing System

    NOAA

    Description

    National Oceanic and Atmospheric Administration - 17 / 18 / 19 / 20 / 21

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    NOAA
    Orbital Altitude
    834 km
    Equatorial Crossing Times
    13:25 asc

    SNPP

    Description

    Suomi National Polar-orbiting Partnership

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    NOAA
    Orbital Altitude
    833 km
    Equatorial Crossing Times
    13:25 asc

    VIIRS

    Description

    Visible Infrared Imaging Radiometer Suite

    Platforms
    Instrument Types
    Imager
    Organizations
    NASA

    Wang M., L. Jiang, K. Mikelsons, X. Liu, Satellite-derived global chlorophyll-a anomaly products, International Journal of Applied Earth Observation and Geoinformation, Volume 97, 2021, 102288,  https://doi.org/10.1016/j.jag.2020.102288.

    ** When you use our data, please reference the product citation (if available) and acknowledge "NOAA CoastWatch" **