Optical Properties In The Southern Yellow Sea

Optical technology has a continuous development in marine science application. Typical Case Ⅱ water in China sea is turbid and its composition is complex, it has become the frontiers and difficulties in marine optics research. This thesis is based on field measurement optical data of the southern Yellow Sea in summer of2013, has researched inherent and apparent optical properties, explored the feasibility and applicability of photobiology optics algorithm inverting concentration of chlorophyll a (Chl-a) and Paniculate Organic Carbon (POC), and discussed the regional environmental significances of optical properties in the southern Yellow Sea.Firstly, we processed the inherent and apparent optical data collected in this cruise basing on behavior of instruments and recent research achievements. The data contains:absorption coefficient (a-Sphere; water sample dealt with QFT); backscattering coefficient (HS6); water-leaving radiance (C-OPS); remote-sensing reflectance (C-OPS); diffuse attenuation coefficient (C-OPS). As well as seawater biochemistry data, such as concentration of Chl-a, concentration of POC and so on.According to the result of data processing, we found out the characteristic region (123～125°E,32～34°N) of seabed resuspension in the southern Yellow Sea, analyze the pure and turbid transition of the southern Yellow Sea surface water, and speculate the characteristic water mass invasion at the mouth of the Yangtze River in the East Sea. After the study of the relationship between different optical quantities, we found the relationship between remote-sensing reflectance and the ratio of backscattering coefficient to the sum of absorption and backscattering coefficient have a good effect, and the green light has the highest fitting correlation coefficient. The contrast diffuse attenuation coefficient at490nm wavelength (Kd490) derived from empirical statistical algorithm and a quasi-analytical algorithm indicated that empirical statistical algorithm have a better performance for cleaner water, quasi-analytical algorithm have a more accurate calculation of the range of Kd490.Then, in the phytoplankton absorption spectra photobiology model deriving concentration of Chl-a we found the relationship between phytoplankton absorption coefficient at675nm wavelength and Chl-a is better than443nm wavelength; when it comes to empirical statistical algorithm, the data result indicated that OC4algorithm is not suitable for the southern Yellow Sea, then we established Chl-a algorithm in the southern Yellow Sea derived from maximum band ratio (MBR) basing on Clark Model. POC deriving algorithm which based on the B-G band ratio of remote-sensing reflectance is still applicable in the southern Yellow Sea Case II water, while single-wavelength two-step empirical algorithm is not applicable. In the study of the relationship between backscattering coefficient and hydrologic condition we found that change in backscattering coefficient and thermocline or halocline have good relationship.Finally, according to hydrologic condition, water mass, sea current, terrestrial source, sea-bottom deposit and other factors, the southern Yellow Sea is divided into five districts in the spatial distribution:Yangtze Delta plume, Yellow Sea warm current area, the southern Yellow Sea cold water mass area, Qingdao cold water mass area and north Jiangsu shallow area. And then qualitative and quantitative analysis of the optical characteristics of each area were discussed.