We have developed a novel target set to scale our Underwater Laser-illuminated Range-gated Imaging (ULRI) video system in a 3 m-tank with turbid water (attenuation coefficient 1.0 m -1). As light speed in water is 22....We have developed a novel target set to scale our Underwater Laser-illuminated Range-gated Imaging (ULRI) video system in a 3 m-tank with turbid water (attenuation coefficient 1.0 m -1). As light speed in water is 22.5 cm ns -1, the target set consists of a series of 3-bar targets at 22.5 cm intervals along the laser illumination direction, with the targets separated vertically. As a result, a sequence of good gated images, in steps of 1 ns delay, is presented, which is a revelation of the ‘sliced-view’ phenomenon for ns-level range-gating in such a limited water body. The Depth of Gating (DOG) and DOG-profile of the URLI system are measured for the first time, which can be used for evaluating gating-performance efficiently.展开更多
Seasonal variation of the Tianjin coastal atmospheric aerosol opticalproperties are important for improving the atmosphere correction precision of marinesatellite and learning the environment of the boundary between t...Seasonal variation of the Tianjin coastal atmospheric aerosol opticalproperties are important for improving the atmosphere correction precision of marinesatellite and learning the environment of the boundary between the Bohai Sea and theland. In this paper, the aerosol optical data of Tianjin coastal area from April 2010 toMay 2011 were observed by using the CE317 Solar Photometer, and the aerosol opticalproperties were analyzed. The results show that: Aerosol Optical Thickness (AOT)spectra are basically in accord with Angstrom relationship; there are three basic typesof AOT daily variations, which are rising type, levelling type, and declining type; inTianjin Coastland, the mean value of AOT is highest in autumn, which is 0.686. Thevalue is lower in spring and summer, and hits the lowest point in winter. Angstromexponent α increases successively from spring, summer, autumn to winter. Due to thedusty, the angstrom exponent α in spring is lowest, the mean of which is 0.854.Compared with Qingdao Coastland, the atmospheric aerosol optical properties presentcharacteristics of regionality.展开更多
Aimed at high turbid coastal waters, an improved algorithm for retrieval ofaerosol optical properties from Geostationary Ocean Color Imager （GOCI） is proposed.The algorithm adopts support vector machine （SVM） to s...Aimed at high turbid coastal waters, an improved algorithm for retrieval ofaerosol optical properties from Geostationary Ocean Color Imager （GOCI） is proposed.The algorithm adopts support vector machine （SVM） to separate the interfering signalof phytoplankton pigments, suspended matter and chromophoric dissolved organicmatter （CDOM）. Radioactive Transfer Model （RTM） Rstar5b is utilized to simulate thetransmitting process. The algorithm can retrieve aerosol optical depth （AOD） andaerosol types simultaneously. In the study, the aerosol optical depth was retrieved overthe turbid waters in the summer of 2014 and 2015. The results of inversion werecompared with the corresponding AERONET data and GOCI service product toestimate the accuracy of the advanced method. The study shows that this algorithmhas better performance compared with GOCI service algorithm for turbid water in theYellow Sea.展开更多
文摘We have developed a novel target set to scale our Underwater Laser-illuminated Range-gated Imaging (ULRI) video system in a 3 m-tank with turbid water (attenuation coefficient 1.0 m -1). As light speed in water is 22.5 cm ns -1, the target set consists of a series of 3-bar targets at 22.5 cm intervals along the laser illumination direction, with the targets separated vertically. As a result, a sequence of good gated images, in steps of 1 ns delay, is presented, which is a revelation of the ‘sliced-view’ phenomenon for ns-level range-gating in such a limited water body. The Depth of Gating (DOG) and DOG-profile of the URLI system are measured for the first time, which can be used for evaluating gating-performance efficiently.
基金supported by Science Foundation for The Excellent Youth Scholars of Tianjin
文摘Seasonal variation of the Tianjin coastal atmospheric aerosol opticalproperties are important for improving the atmosphere correction precision of marinesatellite and learning the environment of the boundary between the Bohai Sea and theland. In this paper, the aerosol optical data of Tianjin coastal area from April 2010 toMay 2011 were observed by using the CE317 Solar Photometer, and the aerosol opticalproperties were analyzed. The results show that: Aerosol Optical Thickness (AOT)spectra are basically in accord with Angstrom relationship; there are three basic typesof AOT daily variations, which are rising type, levelling type, and declining type; inTianjin Coastland, the mean value of AOT is highest in autumn, which is 0.686. Thevalue is lower in spring and summer, and hits the lowest point in winter. Angstromexponent α increases successively from spring, summer, autumn to winter. Due to thedusty, the angstrom exponent α in spring is lowest, the mean of which is 0.854.Compared with Qingdao Coastland, the atmospheric aerosol optical properties presentcharacteristics of regionality.
基金supported by Tianjin Natural Science Foundation Project(14JCYBJC22500)
文摘Aimed at high turbid coastal waters, an improved algorithm for retrieval ofaerosol optical properties from Geostationary Ocean Color Imager （GOCI） is proposed.The algorithm adopts support vector machine （SVM） to separate the interfering signalof phytoplankton pigments, suspended matter and chromophoric dissolved organicmatter （CDOM）. Radioactive Transfer Model （RTM） Rstar5b is utilized to simulate thetransmitting process. The algorithm can retrieve aerosol optical depth （AOD） andaerosol types simultaneously. In the study, the aerosol optical depth was retrieved overthe turbid waters in the summer of 2014 and 2015. The results of inversion werecompared with the corresponding AERONET data and GOCI service product toestimate the accuracy of the advanced method. The study shows that this algorithmhas better performance compared with GOCI service algorithm for turbid water in theYellow Sea.
