MERSEA merseaip@ifremer.fr 2007-04-27 Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif FTP/netCDF 3.X mersea-oc@jrc.it]]> Baltic subset: 9 Mbytes (bzip2 compressed) ftp://mersea.jrc.ec.europa.eu/kd490/seawifs/balt ftp Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif FTP/netCDF 3.X mersea-oc@jrc.it]]> Mediterranean subset: 28 Mbytes (bzip2 compressed) ftp://mersea.jrc.ec.europa.eu/kd490/seawifs/medi ftp Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif FTP/netCDF 3.X mersea-oc@jrc.it]]> North Atlantic Drift subset: 97 Mbytes (bzip2 compressed) ftp://mersea.jrc.ec.europa.eu/kd490/seawifs/nadr ftp Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif FTP/netCDF 3.X mersea-oc@jrc.it]]> North-East Atlantic Subtropical Gyre subset: 96 Mbytes (bzip2 compressed) ftp://mersea.jrc.ec.europa.eu/kd490/seawifs/nase ftp Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif FTP/netCDF 3.X mersea-oc@jrc.it]]> Atlantic Sub-Arctic subset 1.9Gbytes (bzip2 compressed) ftp://mersea.jrc.ec.europa.eu/k490/seawifs/sarc ftp Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif DAP 2 mersea-oc@jrc.it]]> Baltic subset: N/A http://mersea.jrc.ec.europa.eu/thredds/dodsC/kd490_seawifs_balt.html http Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif DAP 2 mersea-oc@jrc.it]]> Mediterranean subset: N/A http://mersea.jrc.ec.europa.eu/thredds/dodsC/kd490_seawifs_medi.html http Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif DAP 2 mersea-oc@jrc.it]]> North Atlantic Drift subset: N/A http://mersea.jrc.ec.europa.eu/thredds/dodsC/kd490_seawifs_nadr.html http Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif DAP 2 mersea-oc@jrc.it]]> North Atlantic Drift subset: N/A http://mersea.jrc.ec.europa.eu/thredds/dodsC/kd490_seawifs_nase.html http Joint Research Center (EC)mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif DAP 2 mersea-oc@jrc.it]]> Atlantic Sub-Arctic subset: N/A http://mersea.jrc.ec.europa.eu/thredds/dodsC/kd490_seawifs_sarc.html http SeaWiFS Sea Surface Diffuse Attenuation Coefficient at 490nm JRC-EUR-SEAWIFSK490-OBS General information : Monthly mean sea surface diffuse attenuation coefficient at 490nm in m-1 derived from the SeaWiFS sensor.
Processing information: Kd(490) data is reprocessed (V1.1) by the Goddard Space Flight Centre (NASA) using SeaDAS 4.9 and the standard algorithm for Kd(490) (Werdell 2005).
Temporal characteristics: This dataset comprises of standard mapped image monthly mean sea surface layer Kd(490) maps at 2km resolution (L3 product).
Description of observation methods/instruments: The remote sensing of 'Ocean Colour' represents a measure of the spectral variations in the light leaving the water surface, subsequently interpreted in terms of concentrations of optically-significant constituents in the water. The electromagnetic signal collected by the sensor on-board the satellite is largely determined by photons that have never reached the water surface, but have been backscattered within the atmosphere through multiple interactions between gas molecules and aerosols. After removing the atmospheric contribution, the water leaving radiance recorded at a given time by the satellite reflects the optical properties of the water which, in turn, mirrors a specific structure and biogeochemical composition of the marine waters. The satellite-derived reflectance at the air-sea interface can be related to apparent optical properties such as Kd(490).
Quality/accuracy/calibration information: The algorithm is an empirical band-ratio formula, with retrieval standard error and r^2 (for log-transformed data) of 0.28 and 0.89, respectively, as calculated over the development in situ data set (Werdell 2005).
Suitability: Satellite Ocean colour imagery provides useful information on optical properties that is routinely available on a global basis. Kd(490), as diffuse attenuation coefficient, can serve to model the light propagation in the water column in the visible spectral range, and is thus of potential use for physical and ecosystem numerical models. The associated satellite-derived fields can be directly assimilated into numerical models using data insertion and adjoint methods.
This product is available in different regional subsets:

• Baltic subset: 3.5E to 30.5E, 52.75N to 66.0N
• North Atlantic Drift subset: -40.0E to 12.5E, 35.0N to 65.0N
• Mediterranean subset: -6.0E to 36.5E, 30.0N to 46.0N
• North-East Atlantic Subtropical Gyre subset: -40.0E to -5.0E, 10.0N to 45.0N
• Atlantic Sub-Arctic subset: -40.0E to 40.0E, 55.0N to 80.0N

Expected type of users: The product is suitable for studies of ecosystem dynamics and physical circulation (radiative budget). It is also designed for assimilation into models operated by the Mersea forecasting TEPs as these users need products with appropriate documentation and assessed uncertainties.
References:

• Werdell, P.J. (2005). Ocean color K490 algorithm evaluation.http://oceancolor.gsfc.nasa.gov/REPROCESSING/SeaWiFS/R5.1/k490_update.html

Other contextual information: The product is stored in NetCDF data confirming to the COARDS-CF conventions and delivered through FTP, OpenDAP and Live Access Server (work in progress).
]]> Joint Research Center (EC) mersea-oc@jrc.ithttp://www.jrc.ec.europa.euhome web pagehttp://www.mersea.eu.org/images/logos/partne5.gif Remote sensing TEP webmaster-mersea@mersea.eu.orghttp://w3.mersea.eu.org/html/remote_sensing/welcome.htmlhome web page Remote Sensing datasets Gridded (analysis) CPWC: Chlorophyll pigment concentrations in the water column concentration_of_chlorophyll_in_sea_water,kg m-3,CF http://www.mersea.eu.org/images/products-quicklooks/JRC-EUR-SEAWIFSK490-OBS.gif product QuickLook GIF 2 km -40.0 40.0 10.0 80.0 vertical : Ocean surface, geographical : Regional scale, temporal : Delayed Mode, 0 0 meters 1997-09-01 north east atlantic 48.27,-35 63,-35 63,7 59,11 57.44,10.30 53.49,9.23 48.27,-1.24 48.27,-35 arctic 63,-35 90,-35 70,30 63,7 63,-35 baltic sea 66.20,20 66.20,26 59.5,30.19 53.49,20.55 53.49 9.23 57.44,10.30 59,11 66.20,20 mediterranean sea 35.47,-5.54 36.15,-5.54 46,5 46,15 40.25,26.41 38,38 30,35 29,19 35.47,-5.54 temporal resolution : monthly partner 4326