TY - JOUR
T1 - Improving the description of sunglint for accurate prediction of remotely sensed radiances
AU - Ottaviani, Matteo
AU - Spurr, Robert
AU - Stamnes, Knut
AU - Li, Wei
AU - Su, Wenying
AU - Wiscombe, Warren
PY - 2008/9
Y1 - 2008/9
N2 - The bidirectional reflection distribution function (BRDF) of the ocean is a critical boundary condition for radiative transfer calculations in the coupled atmosphere-ocean system. Existing models express the extent of the glint-contaminated region and its contribution to the radiance essentially as a function of the wind speed. An accurate treatment of the glint contribution and its propagation in the atmosphere would improve current correction schemes and hence rescue a significant portion of data presently discarded as "glint contaminated". In current satellite imagery, a correction to the sensor-measured radiances is limited to the region at the edge of the glint, where the contribution is below a certain threshold. This correction assumes the sunglint radiance to be directly transmitted through the atmosphere. To quantify the error introduced by this approximation we employ a radiative transfer code that allows for a user-specified BRDF at the atmosphere-ocean interface and rigorously accounts for multiple scattering. We show that the errors incurred by ignoring multiple scattering are very significant and typically lie in the range 10-90%. Multiple reflections and shadowing at the surface can also be accounted for, and we illustrate the importance of such processes at grazing geometries.
AB - The bidirectional reflection distribution function (BRDF) of the ocean is a critical boundary condition for radiative transfer calculations in the coupled atmosphere-ocean system. Existing models express the extent of the glint-contaminated region and its contribution to the radiance essentially as a function of the wind speed. An accurate treatment of the glint contribution and its propagation in the atmosphere would improve current correction schemes and hence rescue a significant portion of data presently discarded as "glint contaminated". In current satellite imagery, a correction to the sensor-measured radiances is limited to the region at the edge of the glint, where the contribution is below a certain threshold. This correction assumes the sunglint radiance to be directly transmitted through the atmosphere. To quantify the error introduced by this approximation we employ a radiative transfer code that allows for a user-specified BRDF at the atmosphere-ocean interface and rigorously accounts for multiple scattering. We show that the errors incurred by ignoring multiple scattering are very significant and typically lie in the range 10-90%. Multiple reflections and shadowing at the surface can also be accounted for, and we illustrate the importance of such processes at grazing geometries.
KW - Aerosols
KW - Atmospheric scattering
KW - Multiple reflections
KW - Ocean BRDF
KW - Shadowing
UR - http://www.scopus.com/inward/record.url?scp=48949115300&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=48949115300&partnerID=8YFLogxK
U2 - 10.1016/j.jqsrt.2008.05.012
DO - 10.1016/j.jqsrt.2008.05.012
M3 - Article
AN - SCOPUS:48949115300
SN - 0022-4073
VL - 109
SP - 2364
EP - 2375
JO - Journal of Quantitative Spectroscopy and Radiative Transfer
JF - Journal of Quantitative Spectroscopy and Radiative Transfer
IS - 14
ER -