Full description
The NOAA20 satellite platform carries a VIIRS sensor that observes sunlight reflected from within the ocean surface layer at multiple wavelengths. These measurements at discrete wavelengths represent the spectrum of light leaving the water surface, and the shape of the spectrum is characteristic of the water optical properties.Moore et al. (2009, RSE, 113, pp2424-2430, doi:10.1016/j.rse.2009.07.016) applied a clustering technique to spectra to identify 8 sets of discrete optical water types for data from the MODIS sensor. This product "owtd_csiro" is produced using a CSIRO implementation of the Moore et al. algorithm, and testing shows that it closely reproduces the results of the original Moore et al implementation in the NASA SeaDAS package. The CSIRO implementation was created because the implementation in SeaDAS has not been kept up to date, and to extend the product to the VIIRS sensor.
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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.owtd_csiro.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/noaa20/catalog.html![]()
(Satellite Remote Sensing page on IMOS website)
url :
http://imos.org.au/srs.html![]()
(Moore et al. 2009 paper)
doi :
https://doi.org/10.1016/j.rse.2009.07.016![]()
SRS - OWTD - WMS layer (srs_oc_noaa20_owtd_csiro_url/owtd_csiro)
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_owtd_csiro_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_owtd_csiro_url#file_url)
url :
https://geoserver-123.aodn.org.au/geoserver/ows![]()
(ncUrlList help documentation)
url :
https://help.aodn.org.au/web-services/ncurllist-service/![]()
global : 8209bf83-0c3c-4fbe-9f36-41f7a5ee9913
- global : 5f359ca7-396a-4c1a-8388-77a50ad39859
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