SeaWiFS Sea Surface Diffuse Attenuation Coefficient at 490nm

JRC-EUR-SEAWIFSK490-OBS

Remote Sensing datasets

Gridded (analysis)

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

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

• concentration_of_chlorophyll_in_sea_water,kg m-3,CF

Regional scale

2 km

from 0 to 0 meters.