GOCI 알고리즘을 위한 한반도 주변 해역의 광학적 특성

Abstract

GOCI, the first Geostationary Ocean Color Imager, shall be operated in a staring-frame capture mode onboard its Communication Ocean and Meteorological Satellite (COMS) and tentatively scheduled for launch in 2008. The mission concept includes eight visible-to-near-infrared bands, 0.5 km pixel resolution, and a coverage region of 2,500 × 2,500 km centered at Korea. The GOCI is expected to provide SeaWiFS quality observations for a single study area with imaging interval of 1 hour from 10 am to 5 pm. In the GOCI swath area, the optical properties of the East Sea (typical of Case-I water), the Yellow Sea and East China Sea (typical of Case-II water) are studied. For developing the GOCI ocean color algorithms in optically more complex waters, it is necessary to study and understand the optical properties around the Korean Sea. Radiometric measurements were made using WETLabs AC-S, TriOS RAMSES ACC/ARC, and ASD FieldSpec Pro Dual VNIR Spectroradiometer. Seawater samples were collected concurrently with the radiometric measurements at about 200 points around the Korean Sea during 1998 to 2006. The absorption coefficients were determined using Perkin-Elmer Lambda 19 dual-beam spectrophotometer. We analyzed the absorption coefficient of sea water constituents such as phytoplankton, Suspended Sediment (SS) and Dissolved Organic Matter (DOM). Phytoplankton exhibited the pronounced absorption features at 440nm, 465nm and 675nm. Some cases exhibited the absorption features at 550 nm. Absorption coefficient values of phytoplankton at 443nm appeared range from 0.02 to 0.11 m-1. The general trend of phytoplankton absorption coefficients increased with increasing Chl-a concentration. The large variations of phytoplankton absorption spectral features were observed in southern Korean Sea, while not much variation in the spectral patterns of the absorption spectral values were observed in the East Sea and West and Yellow Sea. The sources of variability in spectral absorption of phyto