Temporal And Spatial Distribution Characteristics Of Yellow Substance In Yellow Sea And East China Sea

Yellow substance could affect global biogeochemical cycles, optical field distribution in water and phytoplankton photosynthesis. Meanwhile, it is of great significance to water pollution monitoring and evaluation as same as water mass division. In this paper, field measurement data is used to study the concentration distribution of yellow substance and analyze the main factors. Parameters of yellow substance absorption coefficient inversion method by Dong et al. are adjusted and checked using field measurement data. And it is applied in the absorption coefficient inversion of yellow substance in East China Sea. Monthly changes, seasonal changes and inter annual variations of the typical point in East China Sea were analyzed. The main research results are listed as follows:1. The spring and autumn field measurement data of two typical cross sections in East China Sea is analyzed to study the concentration distribution of yellow substance. The results shows that, for the vertical distribution of yellow substance, high concentration is in the lower layer and near-shore area, low concentration is in the upper layer and off-shore area. In the Northern Yellow Sea, yellow substance concentration-distribution is mixed in autumn. By the influence of the land runoff, yellow substance concentration is relatively large. But as the thermocline and halocline begins to form in spring, yellow substance concentration is gradually stratified; In the South Yellow Sea, yellow substance concentration is also mixed in autumn and the concentration in nearshore is relatively large. The yellow substance concentration is still mixed in spring. In short, the differences of yellow substance in different sea area have close relationship with the dynamic environment, the difference of thermocline and halocline and phytoplankton growth factors.2. Parameters of yellow substance absorption coefficient inversion method by Dong et al. are adjusted using field measurement data and is validated in applicability. The correlation coefficient between the absorption value which is derived from the adjusted inversion algorithm and the measured value is 0.738 and the root mean square error is 0.035, which means that the algorithm can meet the requirements of analysis of absorption coefficient of yellow substance.3. Applying the improved algorithm in 17 years’ satellite data from 1998 to 2014 in East China Sea, the horizontal distribution characteristics of yellow substance absorption coefficient were concluded. The results showed that, in the aspects of seasonal changes, the absorption coefficient is higher in winter and spring, lower in summer, highest in April and lowest in August or September. The yellow substance absorption coefficient and chlorophyll concentration showed a good correlation in the central area of the Southern Yellow Sea and Northern Yellow Sea, as well as the offshore of East China Sea. In the aspects of inter annual changes, the yellow substance absorption coefficient and chlorophyll concentration showed a good correlation in the 1-9 year time scale, and the relation is gradually increased from the central area of Northern Yellow Sea, the Central of Southern Yellow Sea to the offshore of East China Sea. In addition, in the long time scale of more than 9 years, the grow of chlorophyll concentration in the central Southern Yellow Sea and Northern Yellow Sea is not accompanied by an increase the yellow substance, which may be related to the local climate and environment, which is still needed further research.