Full description
The NOAA20 satellite platform carries a VIIRS sensor that observes sunlight reflected from within the ocean surface layer at multiple wavelengths. These multi-spectral measurements are used to infer the concentration of chlorophyll-a (Chl-a), most typically due to phytoplankton, present in the water.There are multiple retrieval algorithms for estimating Chl-a. These data use the OCI method (Hu et al 2012, doi: 10.1029/2011jc007395) recommended by the NASA Ocean Biology Processing Group and implemented in the SeaDAS processing software l2gen. The OCI algorithm is described at https://oceancolor.gsfc.nasa.gov/atbd/chlor_a/ (and links therein).
Lineage
Statement: The radiometric sensitivity of the VIIRS sensor is evolving continuously during its mission and is monitored regularly by NASA. The SeaDAS software uses tables of calibration coefficients that are updated periodically. From time to time upgrades to the algorithms and/or the format of the calibration tables are required, in which case a new version of SeaDAS is released. These data were initially being produced using SeaDAS 8.x and more recently, with SeaDAS 9.x. The data are produced by combining the near real time (nrt) data stream from all the available direct broadcast reception stations in Australia with delayed-mode data from NASA in the US. The data have been remapped from satellite projection into a geographic (Latitude/Longitude axes) projection (0.01 degree sampling) and are presented as a sequence of daily mosaics covering the region (80 <= Longitude <= 180, -60 <= Latitude <= +10) formatted as CF-compliant netCDF files. It should be noted that the data are not processed until the definitive spacecraft ephemeris becomes available, usually 12-24 hours after the overpass. This means that the geolocation should be of a uniformly high standard. The filenames are of the form J.P1D.yyyymmddThhmmssZ.aust.chl_oci.nc, where 'J' denotes NOAA20/VIIRS, 'yyyymmddThhmmssZ' is the GMT date of the mosaic, 'aust' indicates a whole-of-Australia mosaic and the 'nc' suffix is for netCDF4 format data files. Files are written in netCDF4 format with compression.Notes
CreditAustralia’s Integrated Marine Observing System (IMOS) is enabled by the National Collaborative Research Infrastructure Strategy (NCRIS). It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as Lead Agent.
CSIRO Oceans and Atmosphere
Curtin University
Created: 07 02 2025
Data time period: 2022-05-21
text: westlimit=80.00; southlimit=-60.00; eastlimit=179.90; northlimit=10.00
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(Link to OPENDAP server)
url :
http://thredds.aodn.org.au/thredds/catalog/IMOS/SRS/OC/gridded/snpp/catalog.html![]()
(Satellite Remote Sensing page on IMOS website)
url :
http://imos.org.au/srs.html![]()
SRS - OCI - WMS layer (srs_oc_noaa20_chl_oci_url/chl_oci)
url :
http://geoserver-123.aodn.org.au/geoserver/ncwms![]()
The GoGoDuck subsets and aggregates gridded data. Data is returned as a NetCDF file. (srs_oc_noaa20_chl_oci_url)
url :
https://processes.aodn.org.au/wps![]()
(GoGoDuck help documentation)
url :
https://help.aodn.org.au/web-services/gogoduck-aggregator/![]()
The ncUrlList is a WFS service that returns a list of URLs matching a query. (srs_oc_noaa20_chl_oci_url#file_url)
url :
http://geoserver-123.aodn.org.au/geoserver/ows![]()
(ncUrlList help documentation)
url :
https://help.aodn.org.au/web-services/ncurllist-service/![]()
(Access To AWS Open Data Program registry for the Cloud Optimised version of this dataset)
url :
https://registry.opendata.aws/aodn_satellite_chlorophylla_oci_1day_noaa20/![]()
(Access to Jupyter notebook to query Cloud Optimised converted dataset)
global : 8209bf83-0c3c-4fbe-9f36-41f7a5ee9913
- global : a9e03db8-f277-45d1-821d-cfcbfe8ae6be
.png)