The Scattering Characteristics and Classifications of Particulate Matters in Jiaozhou Bay and Qingdao Coastal Areas
LIU Xiao-yan1, YANG Qian1*, CHEN Shu-guo2, HU Lian-bo2, ZONG Fang-yi1, LIU Qiao-jun1
1. Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao 266000, China
2. College of Information Science and Engineering, Ocean University of China, Qingdao 266000, China
Abstract：Jiaozhou Bay, located in the south of Shandong peninsula, is a semi-closed bay in the west of the Yellow Sea. It is an important representative of the north temperate gulf ecosystem. Because there are insufficient exchange capacities of water bodies and a large number of pollutants it contained, the eutrophication of the Jiaozhou Bay and Qingdao coastal water is still a significant problem. Therefore it is of great significance to effectively monitor the water quality of the regions in near-real time. In August 2014 and October 2015, two field experiments of ocean optics were conducted in the Jiaozhou Bay and Qingdao coastal area. The profiles of absorption spectra and attenuation spectra were measured using the high spectral absorption-attenuation meter ac-s, from which the profiles of scattering spectra were obtained. The backscattering meters, BB9 and HS6, were used to measure the profiles of the backscattering spectra in August 2014 and October 2015, respectively. Then the backscattering ratios of particles were calculated. Based on the measurements, the spectral models of scattering coefficients and backscattering coefficients of suspended particulate matters were developed, respectively. Moreover, the relationship model between the backscattering coefficient and scattering coefficient at 532 nm was developed as well. The particle composition and its spatial distribution in the Jiaozhou Bay and Qingdao coast area were analyzed using the refractive index information obtained from the backscatter ratio. Finally, the relationship between the scattering parameters and particle concentrations SPM was analyzed. The results show that the values of the scattering and backscattering coefficients in the Jiaozhou Bay are generally higher than those in the Qingdao coast area. The closer the stations are to the shore in Jiaozhou Bay, the greater the values are. The slope of the scattering spectral (m=0.56) in the Jiaozhou Bay is larger than that in the Qingdao coastal stations (m=0.44). There is a power regression between the backscattering coefficient and the scattering coefficient of particles in the Jiaozhou Bay and Qingdao coast area. The refractive index of particles in this region ranges from 1.097 to 1.197, from which was inferred that the dominant component was inorganic mineral particles. The refractive index of the stations in the bay mouth (JZ1, QD1 and QD7) changed little. A section composed of stations located inside the bay, in the mouth of the bay and outside the Bay (in the Qingdao coast) were selected to analyze the distribution of the particle refractive index. It was found that the refractive index of particles gradually increased from the inner of the Bay (i. e., JZ9) to the mouth of the Bay (i. e., JZ1), which means more inorganic particles inside the Bay. While the refractive index of particles decreased gradually as farther to the coast (from QD7 to QD5) and the composition of organic particles increased. The refractive index of particles in the JZ6 station that is near the Jiaozhou Bay bridge is significantly lower than the stations on both sides of the bridge. The linear and power exponential relationships between the backscattering coefficients and the concentrations of suspended particulate matters were established. It was found that the power exponential regression is better than the linear regression.
Key words：Case Ⅱ waters; Remote sensing of ocean color; Scattering characteristics; Particle classifications; Jiaozhou Bay and Qingdao coastal area
刘晓燕，杨 倩，陈树果，胡连波，宗芳伊，刘巧君. 胶州湾及青岛近海水中颗粒物散射特性及其分类[J]. 光谱学与光谱分析, 2020, 40(10): 3102-3107.
LIU Xiao-yan, YANG Qian, CHEN Shu-guo, HU Lian-bo, ZONG Fang-yi, LIU Qiao-jun. The Scattering Characteristics and Classifications of Particulate Matters in Jiaozhou Bay and Qingdao Coastal Areas. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2020, 40(10): 3102-3107.
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