Spatial And Temporal Variations Of UV Diffuse Attenuation Coefficient In The Eastern China Seas

Ultraviolet radiation has important influence on underwater biological processes and photochemical processes, and it affects marine ecosystem directly. Eastern China Seas is a place where economy develops relatively active, and it has rich marine resources and complex optical properties. Meanwhile, the physical environmental conditions there have important influence on China. Therefore, research on the spatial and temporal distribution of Ultraviolet radiation in Eastern China Seas and its influence factors has important application value.According to in-situ data, the retrieval algorithm of Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas is established based on multiple linear regression method. Furthermore, it is tested quantitatively by using independent data sets. The results show that the retrieval algorithm is applicable for Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas. Based on the algorithm, long time series data of Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas is obtained by using multi-satellite merging data from 1998 to 2014, while, the spatial and temporal distributions and its influence factors are analyzed.Spatially, Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas appears high in near-shore and low in far-shore. Combined with the inversion data of yellow substance absorption coefficient and suspended particulate matters, reasons of forming spatial distribution of Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas are analyzed. The results show that yellow substance and suspended particulate matters are two main factors. Temporally, the analyse was been achieved from two aspects of seasonal variation and interannual variation. Results show that Ultraviolet Diffuse Attenuation Coefficient in Eastern China Seas appears an overall temporal characteristics of high in winter, spring and autumn come second, and low in summer.Four sections in different sea area are selected to analyze the influence factors of Ultraviolet Diffuse Attenuation Coefficient. Results indicate that yellow substance and total suspended sediments have important effects on the seasonal variation of Ultraviolet Diffuse Attenuation Coefficient in the central Bohai,and yellow substance,total suspended sediments and chlorophyll have important effects on the seasonal variation of Ultraviolet Diffuse Attenuation Coefficient in middle of the central Yellow Sea. Compared to chlorophyll and yellow substance, total suspended sediments are the main factors influencing the seasonal variation of Ultraviolet Diffuse Attenuation Coefficient in the East China Sea. Finally, based on multi-scale wavelet analysis, interannual variations are analyzed from one to nine year cycle and tendency of 17 years. The results show that yellow substance and suspended particulate matters are main influence factors on interannual variations of Ultraviolet Diffuse Attenuation Coefficient in the central Bohai Sea. While yellow substance, suspended particulate matters and chlorophyll have important effects on interannual variations of Ultraviolet Diffuse Attenuation Coefficient in the central Yellow Sea and central East China Sea.