9:00 AM - 9:15 AM
[ACG45-01] Further information in the coastal areas from 250-m resolution multiple bands of GCOM-C “SHIKISAI”
★Invited Papers
Keywords:GCOM-C, SHIKISAI, SGLI , ocean color, remote sensing
Generally, since the optical characteristics of a coastal area is more complicated than an open ocean, it is necessary to take into consideration the regionality of the in-water optical properties (absorption and scattering, and their spectral characteristics) in order to estimate biological variables like a chlorophyll-a concentration from satellite observations. On the other hand, the optical properties may be useful as new environment information if they can be derived correctly.
The Second-generation Global Imager (SGLI) boarded on Global Change Observation Mission - Climate (GCOM-C) has launched in Dec. 2017. Since SGLI has 19 observation channels with 250-m spatial resolution in the visible - infrared wavelengths, applications near the coastal areas are expected to be improved. The SGLI channels (380, 412, 443, 490, 530, 565, 672, and 867 nm) include a near-ultraviolet band (380 nm) and a pair of an absorption and a baseline in comparatively longer wavelengths (530 nm and 565 nm) which can improve estimate of high chlorophyll-a concentration since the absorption is not saturated with the high concentration in the wavelengths.
GCOM-C captured patches where water-leaving reflectance (r_w) of 565-nm, which is derived by the atmospheric radiative transfer code, Pstar-4 (Ota et al., 2010), were especially higher compared with r_w at 530 nm in the central part of the Seto Inland Sea on August 1, 5, and 13 2018. High a_ph/(a_ph+a_dg) ratio areas were captured (Fig. 1) through the in-water optical property model (Lyon and Hoge, 2006; Murakami, 2018) using average spectra of a_ph or a_dg in NOMAD dataset (Werdell, and Bailey, 2005). Generally, difference between absorption coefficients of phytoplankton at 530 nm and 565 nm (a_ph(530nm) - a_ph(565nm)) is larger than difference between absorption coefficient of CDOM + detritus at 530 nm and 565 nm (a_dg(530nm) - a_dg(565nm)). It may correspond to the redtide which has been reported around the area by Fisheries Agency (Fisheries Agency, 2018).
We will continue to make more precise water-leaving spectra to be used for useful information of coastal environment through improvement of correction aerosol absorption and so on.
Reference
Ota, Y., A. Higurashi, T. Nakajima, and T. Yokota, 2010: Matrix formulations of radiative transfer including the polarization effect in a coupled atmosphere-ocean system, J. Quantitative Spectroscopy and Radiative Transfer, 111, 878-894.
Werdell, P. J., and S.W. Bailey, 2005: An improved bio-optical data set for ocean color algorithm development and satellite data product validation, Remote Sens. Environment, 98, 122-140.
Lyon, P., and F. Hoge, 2006: The Linear Matrix Inversion Algorithm, Chap. 7 of IOCCG Report Number 5, Remote Sensing of Inherent Optical Properties: Fundamentals, Tests of Algorithms, and Applications, Ed. by Z. Lee.
Murakami, H., “Ocean color”, Chapter 10 of Meteorological Research Notes, Vol. 238, Geostationary Meteorological Satellites, Himawari-8 and 9 and their applications, M, Ed. by K. Okamoto, K. Bessho, N. Yoshizaki, and H. Murata, Japan Meteorological Society 2018.
Fisheries Management Office, Fisheries Agency, "Red tide in the Seto Inland Sea”, August 2018
The Second-generation Global Imager (SGLI) boarded on Global Change Observation Mission - Climate (GCOM-C) has launched in Dec. 2017. Since SGLI has 19 observation channels with 250-m spatial resolution in the visible - infrared wavelengths, applications near the coastal areas are expected to be improved. The SGLI channels (380, 412, 443, 490, 530, 565, 672, and 867 nm) include a near-ultraviolet band (380 nm) and a pair of an absorption and a baseline in comparatively longer wavelengths (530 nm and 565 nm) which can improve estimate of high chlorophyll-a concentration since the absorption is not saturated with the high concentration in the wavelengths.
GCOM-C captured patches where water-leaving reflectance (r_w) of 565-nm, which is derived by the atmospheric radiative transfer code, Pstar-4 (Ota et al., 2010), were especially higher compared with r_w at 530 nm in the central part of the Seto Inland Sea on August 1, 5, and 13 2018. High a_ph/(a_ph+a_dg) ratio areas were captured (Fig. 1) through the in-water optical property model (Lyon and Hoge, 2006; Murakami, 2018) using average spectra of a_ph or a_dg in NOMAD dataset (Werdell, and Bailey, 2005). Generally, difference between absorption coefficients of phytoplankton at 530 nm and 565 nm (a_ph(530nm) - a_ph(565nm)) is larger than difference between absorption coefficient of CDOM + detritus at 530 nm and 565 nm (a_dg(530nm) - a_dg(565nm)). It may correspond to the redtide which has been reported around the area by Fisheries Agency (Fisheries Agency, 2018).
We will continue to make more precise water-leaving spectra to be used for useful information of coastal environment through improvement of correction aerosol absorption and so on.
Reference
Ota, Y., A. Higurashi, T. Nakajima, and T. Yokota, 2010: Matrix formulations of radiative transfer including the polarization effect in a coupled atmosphere-ocean system, J. Quantitative Spectroscopy and Radiative Transfer, 111, 878-894.
Werdell, P. J., and S.W. Bailey, 2005: An improved bio-optical data set for ocean color algorithm development and satellite data product validation, Remote Sens. Environment, 98, 122-140.
Lyon, P., and F. Hoge, 2006: The Linear Matrix Inversion Algorithm, Chap. 7 of IOCCG Report Number 5, Remote Sensing of Inherent Optical Properties: Fundamentals, Tests of Algorithms, and Applications, Ed. by Z. Lee.
Murakami, H., “Ocean color”, Chapter 10 of Meteorological Research Notes, Vol. 238, Geostationary Meteorological Satellites, Himawari-8 and 9 and their applications, M, Ed. by K. Okamoto, K. Bessho, N. Yoshizaki, and H. Murata, Japan Meteorological Society 2018.
Fisheries Management Office, Fisheries Agency, "Red tide in the Seto Inland Sea”, August 2018