Dr. Yan Bai Profile

Dr. Yan Bai

at Second Institute of Oceanography SOA

SPIE Involvement:

Author

Publications (55)

Proceedings Article | 14 October 2019 Paper

The spatial distribution of salinity in the Pearl River Estuary in China from space

Zengzhou Hao, Qianguang Tu, Haiqing Huang, Difeng Wang, Yan Bai, Zhihua Mao

Proc. SPIE. 11150, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019

KEYWORDS: Satellites, Diffusion, L band, Radiometry, Microwave radiation, Electromagnetic coupling, New and emerging technologies, Absorption

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Sea surface salinity of ocean waters has been obtained from L-band microwave radiometer on satellite, such SMOS, Aquarius and SMAP. It provides a new technology and way to observe the salinity over large region from space. However, it is still difficult to get the sea surface salinity of the coastal waters due to that the effect on satellite-observed microwave radiance of radio frequency interference over near-shore regions. Fortunately, the colored dissolved organic matter (CDOM) has conservative or semi-conservative property in the freshwater areas of coastal rivers and it has a good linear correlation between the absorption coefficient of CDOM and salinity. Based on those, a conservative mixing relationship between the fresh water from the Pearl River and the sea water from the South China Sea are established and the distribution of sea surface salinity from MODIS-retrieved absorption coefficient of CDOM (a_CDOM) at 355nm wavelength in this study. The linear relationship between salinity and aCDOM at 355 nm under conservative mixing conditions can be established from the in-situ observed salinity and MODIS-retrieved a_CDOM at 355 nm at the central water mass in the Pearl River Estuary and the northern basin region of South China Sea. By comparing daily observed MODIS-retrieved sea surface salinity with the in-site observed salinity, it shows that the salinity retrieved from satellite-based a_CDOM has good agreement with observations, and it can better capture the location of low salinity fresh water in the Pearl River. For the summer averaged satellite-based salinity from 2002 to 2018, sea surface salinity are gradually increases from the vertical coastline to the sea in the Pearl River Estuary region. The salinity in coastal region is low by the effect of the Pearl River diluted water, and the salinity in offshore region is high. On average, the distribution of salinity shows that the diffusion of fresh water from the Pearl River generally spread along the coastline to the east and west in summer, while the runoff on the westward is larger and on the eastward it is affected by some flushing water of other rivers. In the future, MODIS-retrieved salinity can be as a supplement to salinity inversion of Microwave radiometer in the coastal region.

Proceedings Article | 14 October 2019 Presentation + Paper

Variation of summertime sea surface salinity of the Arctic Ocean during 2011-2017

Zike Wang, Yan Bai, Shujie Yu, Bangyi Tao, Qiankun Zhu, Fang Gong

Proc. SPIE. 11150, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019

KEYWORDS: Satellites, Spatial resolution

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Proceedings Article | 14 October 2019 Paper

Threshold stability of different algorithms for green tide detection base on geostationary ocean color imager

Xiaoguang Huang, Difeng Wang, Fang Gong, Xianqiang He, Yan Bai, Zhihong Wang, Qiankun Zhu

Proc. SPIE. 11150, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019

KEYWORDS: Landsat, Detection and tracking algorithms, Imaging systems, Satellites, Satellite imaging, Earth observing sensors

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Proceedings Article | 12 December 2018 Paper

Spectral characteristics of Sargassum horneri in seawater

Xiaoguang Huang, Difeng Wang, Menglin Bao, Fang Gong, Yan Bai

Proc. SPIE. 10850, Ocean Optics and Information Technology

KEYWORDS: MODIS, Landsat, Satellites, Spectroscopy, Remote sensing, Reflectivity, Ocean optics, Buildings, Satellite imaging, Earth observing sensors

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In recent years, blooms of Sargassum horneri have occurred frequently in the Yellow Sea and the East China Sea. Optical satellite remote sensing is an important means to monitor Sargassum horneri, the method being based mainly on exploiting the significant spectral differences between the water mixed with Sargassum horneri and the background seawater. Thus, it is necessary to study the spectral characteristics of Sargassum horneri in seawater with a view to improving measurement accuracy. To date, both laboratory-based experiments concerning the spectral characteristics of Sargassum horneri as well as satellite-based remote sensing monitoring have been performed, but these studies have focused mainly on large areas of Sargassum horneri, and there has been limited recognition of the differences in the spectral characteristics for situations where the Sargassum horneri outbreak is early, and where the Sargassum horneri and the background seawater have just mixed. In this study, experiments have been designed to carefully examine the spectral characteristics of Sargassum horneri in seawater.

The main findings are: (1) In general, the spectral distribution for the two forms of Sargassum (the strip form and the uniformly distributed form) are similar. (2) The peak wavelengths for the two forms of Sargassum horneri in seawater are different. The peak maximum for the strip form is at 825 nm while that for the uniformly distributed form is at 725 nm. Thus, spectral measurements may be used to distinguish between the two forms. (3) The concentration of suspended matter in the background seawater may influence the spectral characteristics of Sargassum horneri in seawater. These findings have great significance for remote sensing of the mixed state of Sargassum horneri in seawater, namely, the possibility for differentiation of the uniformly distributed form and strip distribution form. Also, the results have important implications for remote sensing of Sargassum horneri in seawater where the concentrations of suspended matter are variable.

Proceedings Article | 11 October 2018 Paper

Directional variations in parallel polarized water-leaving radiance for suspended particulate matters in coastal waters based on radiative transfer simulation

Jia Liu, Jiahang Liu, Xianqiang He, Yan Bai, Xiaoyan Chen, Peng Chen, Tieqiao Chen, Yihao Wang, Feng Zhu

Proc. SPIE. 10784, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2018

KEYWORDS: Polarization, Scattering, Sensors, Aerosols, Water, Remote sensing, Reflectivity, Ocean optics, Atmospheric particles, Atmospheric modeling

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Proceedings Article | 11 October 2018 Paper

Polarization characterics of underwater, upwelling radiance of suspended particulate matters in turbid waters based on radiative transfer simulation

Jia Liu, Jiahang Liu, Xianqiang He, Yan Bai, Xiaoyan Chen, Peng Chen, Tieqiao Chen, Yihao Wang, Feng Zhu

Proc. SPIE. 10784, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2018

KEYWORDS: Polarization, Scattering, Sensors, Aerosols, Water, Particles, Mie scattering, Atmospheric particles, Atmospheric modeling, Radiative transfer

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Proceedings Article | 10 October 2018 Presentation + Paper

Abnormal upwelling off the southeast of Vietnam in summer 2016

Zhihong Wang, Xiaoyan Chen, Yan Bai, Xianqiang He, Xiaoping Zhang

Proc. SPIE. 10784, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2018

KEYWORDS: MODIS, Data modeling, Satellites, Climate change, Oceanography, Climatology

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Proceedings Article | 13 October 2017 Paper

Satellite observation of the recent changes of chlorophyll in the South China Sea and Bay of Bengal

Shujie Yu, Xiaoyan Chen, Yan Bai, Teng Li, Tianyu Wang, Fang Gong, Qiankun Zhu

Proc. SPIE. 10422, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017

KEYWORDS: MODIS, Sensors, Satellites, Water, Ocean optics, Climate change, Spatial resolution, Oceanography, Climatology, Earth observing sensors

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The Bay of Bengal (BOB) is a semi-enclosed marginal sea in the northeastern part of the Indian Ocean. The South China Sea (SCS) is almost an enclosed marginal sea and is part of the northwestern Pacific Ocean. Both of them are tropical marginal seas, and have similar hydrological properties, such as high surface temperature, stable thermocline, deep euphotic zone, etc. Moreover, they are all greatly affected by East Asian monsoon and typhoons. However, there are also several significant differences between them. The current circulation structures in the South China Sea are more complex with significant season variations. A large amount of fresh water through river inputs is one of the remarkable hydrological characteristics in the Bay of Bengal. In addition, the Bay of Bengal has a large volume of precipitation. Therefore, it is naturally interesting to investigate the different response of the marine ecological properties represented by chlorophyll concentration to climate change. The Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) mission have provided a successive, long-term observations of global ocean color from space. In this study, we investigate the Chl-a trends in the BOB and SCS during the SeaWiFS and MODIS observation periods (1998-2010 and 2003-2016), respectively. In 1998-2010, Chl-a increased in the western central basin of BOB, while it decreased in almost all other parts. During 2003-2016, Chl-a significantly increased in the western part of BOB, and reduced in the southern part. In the SCS, Chl-a in almost the whole region increased during the SeaWiFS observation period. In 2003-2016, the major rising trends appeared in China and Vietnam coast, the Beibu Gulf, and the Gulf of Thailand. The Chl-a of the Straits of Malacca and the Karimata Straits showed downward trends. The rise in temperature might be the main cause of the Chl-a decrease in the BOB. The deepened MLD and/or decreasing SST may contribute to the increasing Chl-a of the BOB and SCS. Remarkably, coastal Chl-a has continued to rise over the past 19 years. The freshwater input might have significant effect on it.

Proceedings Article | 13 October 2017 Paper

Satellite remote sensing of the aquatic pCO2 in the basin of the South China Sea

Hangyu Lu, Yan Bai, Xiaoyan Chen, Fang Gong, Qiankun Zhu, Difeng Wang

Proc. SPIE. 10422, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017

KEYWORDS: Carbon dioxide, MODIS, Data modeling, Satellites, In situ metrology, Remote sensing, Analytical research, Algorithm development, Thermodynamics, Temperature metrology

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The South China Sea (SCS) is one of the largest marginal seas in the world, and the air-sea CO₂ flux in the SCS may contribute significantly to the global air-sea CO₂ flux. In the past decade, many researches on the aquatic pCO₂ and air-sea CO₂ flux mainly in the north SCS were carried out based on the underway measurement of the pCO₂, and the results revealed that the SCS is a source of the CO₂ as a whole in the annual scale. However, the air-sea CO₂ flux is high spatial variability in the SCS, for example, the north shelf of the SCS is a CO₂ sink while the basin is a source. To monitor the spatial and temporal variations of the air-sea CO₂ flux in the SCS, few satellite remote sensing algorithms have been developed to estimate the aquatic pCO₂ in the north SCS. However, these algorithms are all the empirical models which depend on the training dataset from the in situ measurement. In this study, we apply the semi-analytical algorithm MeSAA to retrieve the aquatic pCO₂ in the SCS basin. The MeSAA algorithm was proposed by the Bai et al. (2016) and was evidenced to be widely applicable to the different marginal seas including the East China Sea and Bering Sea. Based on the underway measured aquatic pCO₂ and water temperature, we found that the variation of the pCO₂ in the SCS basin is mainly controlled by the temperature. In addition, the increase of the atmosphere pCO₂ can also contribute the systematical increase of the aquatic pCO₂. Therefore, we established a semi-analytical algorithm for the aquatic pCO₂ retrieval in the SCS basin, which considers the thermodynamic effect and air-sea CO₂ fluxes. The results showed that the thermodynamic effect in the SCS basin was consistent with the theoretical result with the aquatic pCO₂ increasing 4.23% for the 1°C rising of the water temperature. Moreover, the satellite-retrieved aquatic pCO₂ match well with the in situ pCO₂. Based on the established algorithm, the monthly time-series of the aquatic pCO₂ in the SCS basins from 2003 to 2016 were generated from the MODIS datasets from both the Aqua and Terra satellite, and the long-term trends of the aquatic pCO₂ in the different parts of the SCS basin were analyzed.

Proceedings Article | 13 October 2017 Paper

Longtime variation of phytoplankton in the South China Sea from the perspective of carbon fixation

Teng Li, Yan Bai, Xiaoyan Chen, Qiankun Zhu, Fang Gong, Difeng Wang

Proc. SPIE. 10422, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017

KEYWORDS: Carbon, Satellites, Water, Remote sensing, Ocean optics, Ecosystems, Climate change, Oceanography, Atmospheric particles, Carbon sequestration

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Proceedings Article | 13 October 2017 Paper

Unusual phytoplankton blooms in the southwestern Bay of Bengal: a comparative study

Xiaoyan Chen, Yan Bai, Xianqiang He, Shaolei Lu, Shujie Yu

Proc. SPIE. 10422, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017

KEYWORDS: Climate change

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SPIE Journal Paper | 5 January 2017

Assessment of satellite-based chlorophyll-a retrieval algorithms for high solar zenith angle conditions

Hao Li, Xianqiang He, Yan Bai, Xiaoyan Chen, Fang Gong, Qiankun Zhu, Zifeng Hu

JARS Vol. 11 Issue 01

KEYWORDS: Satellites, Algorithm development, Avalanche photodetectors, In situ remote sensing, MODIS, Remote sensing, Ocean optics, Reflectivity, Sensors, Water

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Proceedings Article | 19 October 2016 Paper

The vertical distribution of the beam attenuation coefficient and its correlation to the particulate organic carbon in the north South China Sea

Wansong Cui, Difeng Wang, Fang Gong, Yan Bai, Lin Zhang, Qiankun Zhu, Peng Chen

Proc. SPIE. 9999, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2016

KEYWORDS: Carbon, Lithium, Optical properties, Signal attenuation, Satellites, Water, Particles, Organic materials, Algorithm development, Absorption

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Proceedings Article | 19 October 2016 Paper

A coordinated retrieval method for sea surface salinity based on SMOS and ocean color data

Peng Chen, Tianyu Wang, Zhihua Mao, Yan Bai, Zengzhou Hao

Proc. SPIE. 9999, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2016

KEYWORDS: Code division multiplexing, Contamination, Soil science, Satellites, Water, Luminescence, Spatial resolution, Oceanography, Electromagnetic coupling, Absorption

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Proceedings Article | 19 October 2016 Paper

Assessment of satellite retrieval algorithms for chlorophyll-a concentration under high solar zenith angle

Hao Li, Xianqiang He, Yan Bai, Xiaoyan Chen, Fang Gong, Qiankun Zhu, Zifeng Hu

Proc. SPIE. 9999, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2016

KEYWORDS: Avalanche photodetectors, MODIS, Data storage, Satellites, Water, Remote sensing, Reflectivity, Ocean optics, Algorithm development, In situ remote sensing

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Proceedings Article | 19 October 2016 Paper

A temperature calibration method for CDOM fluorescence LIF LiDAR

Peng Chen, Zhihua Mao, Haiqing Huang, Yan Bai, Tianyu Wang

Proc. SPIE. 9999, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2016

KEYWORDS: LIDAR, Sensors, Calibration, Water, Luminescence, Laser induced fluorescence, Raman spectroscopy, Ocean optics, Raman scattering, Temperature metrology

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Proceedings Article | 19 October 2016 Paper

Satellite views of the massive algal bloom in the Persian Gulf and the Gulf of Oman during 2008-2009

Shujie Yu, Fang Gong, Xianqiang He, Yan Bai, Qiankun Zhu, Difeng Wang, Peng Chen

Proc. SPIE. 9999, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2016

KEYWORDS: Transparency, MODIS, Satellites, Water, In situ metrology, Remote sensing, Nitrogen, Satellite imaging, Oceanography, Climatology

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The Persian Gulf and the Gulf of Oman locate at the northwest of the Arabian Sea, with the total area more than 50,0000 km². The Persian Gulf is a semi-enclosed subtropical sea with high water temperature, extremely high salinity, and an average depth of 50 meters. By the Strait of Hormuz, the Persian Gulf is connected to the Gulf of Oman which is significantly affected by the monsoonal winds and by water exchange between the Arabian Sea and the Persian Gulf. Algal blooms occurred frequently in the Persian Gulf and the Gulf of Oman, and some of them are harmful algal blooms which may lead to massive fish death and thereby serious economic loss. Due to the widely spatial coverage and temporal variation, it is difficult to monitoring the dynamic of the algal bloom based on in situ measurement. In this study, we used the remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to investigate a massive algal bloom event in the Persian Gulf and the Gulf of Oman during 2008-2009. The time series of MODIS-derived chlorophyll concentration (Chl-a) indicated that the bloom event with high Chl-a concentration (~60 percent higher than corresponding climatological data) appeared to lasting more than 8 months from autumn of 2008 to spring of 2009. In addition, the bloom was widespread from the Persian Gulf to the Gulf of Oman and neighboring open ocean. The MODIS-derived net primary production (NPP) collected from MODIS showed the same trend with Chl-a. Multiple forces including upwelling, dust deposition was taken into account to elucidate the mechanisms for the long-lasting algal bloom. The time series chlorophyll concentration of the Persian Gulf emerges a significant seasonal pattern with maximum concentrations seen during the winter time and lowest during the summer. It also indicated slight disturbances occurred in June (May/July) and December (November/ January) in some years. The sea surface temperature and water transparency in the Persian Gulf increased with the rates of 0.3% (<0.01) and 3.02% (p<0.01) during 2003-2014, respectively. Chl-a and NPP declined with the rates of 1.61% (p=0.06) and 1.09% (p=0.08), respectively. However, there are no significant changes of the bloom initiation, termination and duration time among years over 2003-2014.

Proceedings Article | 14 October 2015 Paper

Controlling factors analysis of aquatic pCO2 distribution in the Western Arctic Ocean in summertime

Xuelian Song, Yan Bai, Zengzhou Hao, Qiankun Zhun, Jianyu Chen, Fang Gong

Proc. SPIE. 9638, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2015

KEYWORDS: Carbon, Carbon dioxide, Satellites, Water, Remote sensing, Biological research, Oceanography, Algorithm development, Factor analysis, Thermodynamics

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Proceedings Article | 12 October 2015 Paper

Comparison of different water infrared emissivity retrieval methods with the theoretical model

Ji-An Wei, Difeng Wang, Fang Gong, Yan Bai, Xianqiang He, Jianyu Chen

Proc. SPIE. 9639, Sensors, Systems, and Next-Generation Satellites XIX

KEYWORDS: Thermography, Detection and tracking algorithms, Sensors, Infrared radiation, Radiometry, Algorithm development, Thermal modeling, Atmospheric modeling, Temperature metrology, Algorithms

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Proceedings Article | 10 August 2015 Paper

Thermal infrared radiometer calibration and experimental measurements

JiAn Wei, Difeng Wang, Fang Gong, Bai Yan, Xianqiang He

Proc. SPIE. 9620, 2015 International Conference on Optical Instruments and Technology: Optical Sensors and Applications

KEYWORDS: Thermography, Infrared sensors, Sensors, Calibration, Remote sensing, Black bodies, Infrared radiation, Radiometry, Temperature metrology, Precision calibration

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Proceedings Article | 14 October 2014 Paper

Are the trends in the surface chlorophyll opposite between the South China Sea and the Bay of Bengal?

Xiaoyan Chen, Delu Pan, Yan Bai, Xianqiang He, Tianyu Wang

Proc. SPIE. 9240, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2014

KEYWORDS: Satellites, Remote sensing, Ocean optics, Ecosystems, Climate change, Pollution control, Oceanography, Data centers, Chlorine, Climatology

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Proceedings Article | 24 October 2013 Paper

Design and construction of Information Systems of Ocean Satellite Monitoring for Air-sea CO2 Flux (IssCO2)

Qiankun Zhu, Lei Fang, Yan Bai, Xianqiang He, Xiaoxiao Sun, Jianyu Chen

Proc. SPIE. 8893, Earth Resources and Environmental Remote Sensing/GIS Applications IV

KEYWORDS: Carbon dioxide, Data modeling, Data storage, Databases, Satellites, Image processing, Remote sensing, Climate change, Oceanography, Data conversion

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Proceedings Article | 19 October 2012 Paper

Assessment of suspended particulate matter concentration retrieved by Aqua-MODIS and SeaWiFS in the East China Sea

Qianfang Cui, Delu Pan, Yan Bai, Xianqiang He, Jianyu Chen

Proc. SPIE. 8532, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2012

KEYWORDS: Magnesium, MODIS, Data modeling, Satellites, Remote sensing, Reflectivity, Tongue, Oceanography, Algorithm development, Performance modeling

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The East China Sea (ECS) is the 11th largest marginal seas around the world. ECS has widely continental shelf, and has relatively high concentration of suspended particulate matter (TSM) affected by the terrestrial material from the large rivers, including the Changjiang River, and also affected by the resuspension in the winter. Recently, several regional algorithms for the TSM retrieval in the ECS have been proposed, such as the algorithms developed by Zhang et al. (2010) and Han et al. (2006). Due to the variation of the optical properties of TSM, it is significant to study whether existing algorithms are adequate and reliable for the inversion of the concentration of TSM in the ECS for all seasons. Yet, up to now, the validation of the satellite retrieved TSM is still lack due to the insufficient of the in-situ data and the standard TSM product in the ECS. In the past three years, we have carried out four seasonal cruises covering the whole ECS, including the spring cruise from May to June 2011, the summer cruise in August 2009, the autumn cruise from November to December 2010, and the winter cruise from December 2009 to January 2010. In this paper, we firstly analyzed the spatial-temporal distribution of the TSM in the ECS. The results showed that there was remarkable seasonal variation with higher concentration in the winter half year and lower concentration in the summer half year. The concentration of TSM was higher inshore than that of offshore. The isolines were parallel to the shoreline as a whole. There was a turbid water tongue with notably seasonal variation spreading to southeast at the 29°N in the middle of the ECS. Finally, based on the remote sensing reflectance retrieved by the Aqua-MODIS and SeaWiFS data, the performance of the four inversion algorithms of TSM were evaluated using the in-situ measured TSM data in the ECS, including the Clark’s model in the SeaDAS, Zhang’s model, Han’s model and Tassan’s model. The results show that all of the TSM retrieved by the four models have large error as compared with the in-situ data, indicating the strong requirement of the improving the TSM retrieval in the ECS.

Proceedings Article | 19 October 2012 Paper

Seasonal and interannual variability of sea surface wind over the China seas and its adjacent ocean from QuikSCAT and ASCAT data during 2000-2011

Xiaoyan Chen, Delu Pan, Xianqiang He, Yan Bai, Yifan Wang, Qiankun Zhu

Proc. SPIE. 8532, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2012

KEYWORDS: Statistical analysis, Calibration, Satellites, Electroluminescence, Data archive systems, Meteorological satellites, Spatial resolution, Oceanography, Data centers, Earth sciences

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Proceedings Article | 19 October 2012 Paper

Vertical profiles of beam attenuation coefficients in East China Sea

Qiong Liu, Delu Pan, Yan Bai, Xuan Zhang, Lin Zhang, Qiankun Zhu

Proc. SPIE. 8532, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2012

KEYWORDS: Optical filters, Optical properties, Scattering, Signal attenuation, Particles, In situ metrology, Remote sensing, Laser scattering, Absorption

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Proceedings Article | 13 October 2011 Paper

HAB detection based on absorption and backscattering properties of phytoplankton

Hui Lei, Delu Pan, Yan Bai, Xiaoyan Chen, Yan Zhou, Qiankun Zhu

Proc. SPIE. 8175, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2011

KEYWORDS: Statistical analysis, Backscatter, Optical properties, Scattering, Satellites, Water, Particles, Remote sensing, Oceanography, Absorption

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The coastal area of East China Sea (ECS) suffers from the harmful algal blooms (HAB) frequently every year in the warm season. The most common causative phytoplankton algal species of HAB in the ECS in recent years are Prorocentrum donghaiense (dinoflagellates), Karenia mikimotoi (dinoflagellates which could produce hemolytic and ichthyotoxins) and Skeletonema costatum (diatom). The discrimination between the dinoflagellates and diatom HAB through ocean color remote sensing approach can add the knowledge of HAB events in ECS and help to the precaution. A series of in-situ measurement consisted of absorption coefficient, total scattering and particulate backscattering coefficient was conducted in the southern coast of Zhejiang Province in May 2009, and the estuary of Changjiang River in August 2009 and December 2010, which encountered two HAB events and a moderate bloom. The Inherent Optical Properties (IOPs) of the bloom waters have significant difference between phytoplankton species in absorption and backscattering properties. The chlorophyll a specific absorption coefficient (a*_phy(λ)) for the bloom patches (chlorophyll a concentration >6mg m^-3) differ greatly from the adjacent normal seawater, with the a*_phy(λ) of bloom water lower than 0.03 m² mg^-1 while the a*_phy(λ) of the adjacent normal seawater is much higher (even up to 0.06 m² mg^-1). Meanwhile, the backscattering coefficients at 6 wavebands (420, 442, 470, 510, 590 and 700nm) are also remarkably lower for bloom waters (<0.01 m^-1) than the normal seawater (> 0.02 m^-1). The backscattering coefficient ratio (Rbp(λ)) is much lower for diatom bloom waters than for dinoflagellates types (0.01079 vs. 0.01227). A discrimination model based on IOPs is established, and several typical dinoflagellates and diatom bloom events including Prorocentrum donghaiense, Karenia mikimotoi and Skeletonema costatum in the ECS are picked out for testing with the MODIS-L2 and L3 ocean color remote sensing products from NASA website. The result proves that the satellite-derived inherent optical properties can be used to HAB detection and the discrimination of HAB species from dinoflagellates and the diatom types in the ECS.

Proceedings Article | 13 October 2011 Paper

Phytoplankton bloom and sea surface cooling induced by Category 5 Typhoon Megi in the South China Sea: direct multi-satellite observations

Xiaoyan Chen, Delu Pan, Xianqiang He, Yan Bai, Difeng Wang

Proc. SPIE. 8175, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2011

KEYWORDS: Carbon, MODIS, Satellites, Remote sensing, Clouds, Data archive systems, Spatial resolution, Oceanography, Scientific research, Earth sciences

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Proceedings Article | 4 November 2010 Paper

The extremely high concentration of suspended particulate matter in Changjiang Estuary detected by MERIS data

Yan Bai, Xianqiang He, Delu Pan, Qiankun Zhu, Hui Lei, Bangyi Tao, Zengzhou Hao

Proc. SPIE. 7858, Remote Sensing of the Coastal Ocean, Land, and Atmosphere Environment

KEYWORDS: Near infrared, Scattering, Aerosols, Remote sensing, Reflectivity, Atmospheric corrections, Rayleigh scattering, Scanning probe microscopy, Algorithm development, Atmospheric particles

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Proceedings Article | 10 September 2009 Paper

The low water-leaving radiances phenomena around the Yangtze River Estuary

Xianqiang He, Yan Bai, Zhihua Mao, Jianyu Chen

Proc. SPIE. 7473, Remote Sensing of the Ocean, Sea Ice, and Large Water Regions 2009

KEYWORDS: Radio optics, Backscatter, Optical properties, Scattering, Water, Particles, Remote sensing, Optical testing, Ocean optics, Absorption

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Proceedings Article | 19 December 2008 Paper

The numerical simulation and remote sensing of the thermal discharge from the Qinshan Nuclear Power Station

Ning Li, Zhi-hua Mao, Qing-he Zhang, Di-feng Wang, Yan Bai, De-lu Pan