Multiple scattering effects on the return spectrum of oceanic high-spectral-resolution lidar

Zhou, Yudi; Chen, Weibiao; Liu, Dong; Cui, Xiaoyu; Zhu, Xiaolei; Zheng, Zhiyao; Li, Qun; Yuting, Tao

doi:10.1364/oe.27.030204

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…where z is travel distance underwater; C is a system constant that includes the laser energy, optical efficiency, detector efficiency, attenuation occurring in the atmosphere between the lidar and the surface, and so on; n is the refractive index of seawater; H is the distance of the instrument from the laser spot at water surface; β is the oceanic backscatter coefficient; and α sea is the lidar attenuation coefficient. Although multiple scattering cannot be negligible under the strong scattering characteristics of seawater, Equation (2) can still be written in the form of a single scattering approximation by introducing the lidar attenuation coefficient [28,29]. The lidar attenuation coefficient has a dependency on the water surface spot diameter with respect to the receiving field and depth.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…However, as the backscatter coefficient β is not homogeneous, the slope method is not applicable in seawater with layered plankton. It has been reported that the accurate retrieval of layered seawater optical properties can be carried out by means of high-spectral-resolution lidar or Raman lidar [28,[40][41][42]. Subsequent hardware improvements will be made to improve the Raman scattering receiving efficiency, and a high-spectral-resolution channel will be added for accurate retrieval in layered water.…”

Section: Other Correction Resultsmentioning

confidence: 99%

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A Shipborne Photon-Counting Lidar for Depth-Resolved Ocean Observation

et al. 2022

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Depth-resolved information is essential for ocean research. For this study, we developed a shipborne photon-counting lidar for depth-resolved oceanic plankton observation. A pulsed fiber laser with frequency doubling to 532 nm acts as a light source, generating a single pulse at the micro-joule level with a pulse width of less than 1 ns. The receiver is capable of simultaneously detecting the elastic signal at two orthogonal polarization states, the Raman scattering from seawater, and the fluorescence signal from chlorophyll A. The data acquisition system utilizes the photon-counting technique to record each photon event, after which the backscattering signal intensity can be recovered by counting photons from multiple pulses. Benefitting from the immunity of this statistical detection method to the ringing effect of the detector and amplifier circuit, high-sensitivity and high-linearity backscatter signal measurements are realized. In this paper, we analyze and correct the after-pulse phenomenon of high-linearity signals through experiments and theoretical simulations. Through the after-pulse correction, the lidar attenuation coefficient retrieved from the corrected signal are in good agreement with the diffuse attenuation coefficients calculated from the in situ instrument, indicating the potential of this shipborne photon-counting lidar for ocean observation applications.

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Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Other Correction Resultsmentioning

confidence: 99%

A Shipborne Photon-Counting Lidar for Depth-Resolved Ocean Observation

et al. 2022

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“…An important leap in retrieval accuracy has been achieved with the high-spectral-resolution lidar (HSRL) technique, which can independently measure backscattering and attenuation by separating the particulate and molecular backscatters in wavelength distribution. This technique has been used for decades in aerosols and clouds measurements based on Cabannes-Brillouin scattering from air molecules with broadening of ~3 GHz 19 – 22 , and was recently developed for aircraft deployment in ocean detections 23 , 24 using the backscatter from water molecules shifted to both sides by ~7–8 GHz at 532 nm 25 – 27 . Despite high efficiency of airborne HSRL, its simultaneous measurements with in situ methods are difficult.…”

Section: Introductionmentioning

confidence: 99%

Shipborne oceanic high-spectral-resolution lidar for accurate estimation of seawater depth-resolved optical properties

et al. 2022

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Lidar techniques present a distinctive ability to resolve vertical structure of optical properties within the upper water column at both day- and night-time. However, accuracy challenges remain for existing lidar instruments due to the ill-posed nature of elastic backscatter lidar retrievals and multiple scattering. Here we demonstrate the high performance of, to the best of our knowledge, the first shipborne oceanic high-spectral-resolution lidar (HSRL) and illustrate a multiple scattering correction algorithm to rigorously address the above challenges in estimating the depth-resolved diffuse attenuation coefficient Kd and the particulate backscattering coefficient bbp at 532 nm. HSRL data were collected during day- and night-time within the coastal areas of East China Sea and South China Sea, which are connected by the Taiwan Strait. Results include vertical profiles from open ocean waters to moderate turbid waters and first lidar continuous observation of diel vertical distribution of thin layers at a fixed station. The root-mean-square relative differences between the HSRL and coincident in situ measurements are 5.6% and 9.1% for Kd and bbp, respectively, corresponding to an improvement of 2.7–13.5 and 4.9–44.1 times, respectively, with respect to elastic backscatter lidar methods. Shipborne oceanic HSRLs with high performance are expected to be of paramount importance for the construction of 3D map of ocean ecosystem.

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Review of airborne oceanic lidar remote sensing

Chen,

Zhang

et al. 2023

Intell. Mar. Technol. Syst.

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Airborne oceanic lidars act as an active remote sensing technique have been proved to be one of the most effective and reliable means of oceanic profile remote sensing. This review aims to provide a comprehensive overview of the principles, methodologies, applications, and prospects of oceanic lidar remote sensing. A survey of the previous studies and works related to these techniques is presented in this paper, emphasizing the different mechanism in system design as well as data processing algorithms and their applications in the remote sensing of oceanic environmental parameters. The airborne lidar systems with multi-channels are designed to significantly improve the data quality and resolution of oceanic biological and geographic profiles. Algorithms for biological product retrieval and simulation based on typical radiation transfer models are described here to stimulate future research into ocean biogeochemistry. The advancement of airborne lidar applications in the near future is also presented.

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Multiple scattering effects on the return spectrum of oceanic high-spectral-resolution lidar

Cited by 5 publications

References 24 publications

A Shipborne Photon-Counting Lidar for Depth-Resolved Ocean Observation

A Shipborne Photon-Counting Lidar for Depth-Resolved Ocean Observation

Shipborne oceanic high-spectral-resolution lidar for accurate estimation of seawater depth-resolved optical properties

Review of airborne oceanic lidar remote sensing

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