High-Frequency Observation of Water Spectrum and Its Application in Monitoring of Dynamic Variation of Suspended Materials in the Hangzhou Bay
DAI Qian1,2, PAN De-lu1, HE Xian-qiang1*, ZHU Qian-kun1, GONG Fang1, HUANG Hai-qing1
1. State Key Laboratory of Satellite Ocean Environment Dynamics, The Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China 2. Key Laboratory of Sustainable Utilization of Technology Research for Fishery Resource of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan 316004, China
Abstract：In situ measurement of water spectrum is the basis of the validation of the ocean color remote sensing. The traditional method to obtain the water spectrum is based on the shipboard measurement at limited stations, which is difficult to meet the requirement of validation of ocean color remote sensing in the highly dynamic coastal waters. To overcome this shortage, continuously observing systems of water spectrum have been developed in the world. However, so far, there are still few high-frequency observation systems of the water spectrum in coastal waters, especially in the highly turbid and high-dynamic waters. Here, we established a high-frequency water-spectrum observing system based on tower in the Hangzhou Bay. The system measures the water spectrum at a step of 3 minutes, which can fully match the satellite observation. In this paper, we primarily developed a data processing method for the tower-based high-frequency water spectrum data, to realize automatic judgment of clear sky, sun glint, platform shadow, and weak illumination, etc., and verified the processing results. The results show that the normalized water-leaving radiance spectra obtained through tower observation have relatively high consistency with the shipboard measurement results, with correlation coefficient of more than 0.99, and average relative error of 9.96%. In addition, the long-term observation capability of the tower-based high-frequency water-spectrum observing system was evaluated, and the results show that although the system has run for one year, the normalized water-leaving radiance obtained by this system have good consistency with the synchronously measurement by Portable spectrometer ASD in respect of spectral shape and value, with correlation coefficient of more than 0.90 and average relative error of 6.48%. Moreover, the water spectra from high-frequency observation by the system can be used to effectively monitor the rapid dynamic variation in concentration of suspended materials with tide. The tower-based high-frequency water-spectrum observing system provided rich in situ spectral data for the validation of ocean color remote sensing in turbid waters, especially for validation of the high temporal-resolution geostationary satellite ocean color remote sensing.
Key words：Water spectrum;High-frequency observation;Ocean color remote sensing;Validation;Suspended material;Tide
戴 乾1,2，潘德炉1，何贤强1*，朱乾坤1，龚 芳1，黄海清1 . 杭州湾水体光谱高频观测及在悬浮物动态变化监测中的应用 [J]. 光谱学与光谱分析, 2015, 35(11): 3247-3254.
DAI Qian1,2, PAN De-lu1, HE Xian-qiang1*, ZHU Qian-kun1, GONG Fang1, HUANG Hai-qing1. High-Frequency Observation of Water Spectrum and Its Application in Monitoring of Dynamic Variation of Suspended Materials in the Hangzhou Bay. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(11): 3247-3254.
[1] Wang X Y, Tang J W, Li T J, et al. Ocean Technology, 2012, 31(1): 72. [2] Bailey S W, Werdell P J. Remote Sensing of Environment, 2006, 102(1): 12. [3] Wang G, Zhou W, Cao W, et al. Marine Pollution Bulletin, 2011, 62(9): 1939. [4] Zibordi G, Holben B, Hooker S B, et al. Eos, Transactions American Geophysical Union, 2006, 87(30): 293. [5] Zibordi G, Mélin F, Berthon J F, et al. Journal of Atmospheric and Oceanic Technology, 2009, 26(8): 1634. [6] Hu J C, Pan D L, Wang D F, et al. Journal of Infrared and Millimeter Wave, 2013, 32(6): 519. [7] Chen S. Science in China Series B: Chemistry, 2001, 44(1): 57. [8] Gordon H R, Wang M. Applied Optics, 1994, 33(3): 443. [9] He X, Pan D, Bai Y, et al. Applied Optics, 2011, 50(22): 4353. [10] Cox C, Munk W. Bulletin of the Scripps Institution of Oceanography, 1956, 6(9): 401. [11] Liu Z G, Zhou G H. Journal of Infrared and Millimeter Wave, 2007, 26(5): 362. [12] He X, Bai Y, Pan D, et al. Optics Express, 2012, 20(18): 20754. [13] He X, Bai Y, Pan D, et al. Remote Sensing of Environment, 2013, 133: 225.
