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Detecting the vertical profile of optical properties is an important task in the remote sensing of the upper ocean, especially for 3-D reconstruction. Ocean color remote sensing can only provide surface information, while the light detection and ranging (lidar) technique can provide depth-resolved data. Lidar can provide global-scale observations of the upper ocean for days and nights with minimal atmospheric correction errors. Unfortunately, due to the strong multiple scattering effects that occur when light propagates in seawater, the simple lidar equation may cause some deviations between the actual measurements and the simulation of the lidar signals. In this paper, we present a shipborne oceanic lidar, which was developed to detect the optical properties of seawater. For evaluating the performance of the lidar system, a Monte Carlo (MC) model was established to simulate lidar signals based on the simultaneous in situ inherent optical properties of seawater. The lidar measurements and the MC simulation can provide both the lidar signals and the retrieved lidar attenuation coefficient $\alpha $. The results of the comparison indicate that the lidar-measured signals correspond well with the MC-simulated signals at different experiment stations in the Yellow Sea and at various receiving fields of view (FOVs). We also observed strong correlations between the lidar-measured $\alpha $ and MC-simulated $\alpha $ at different stations ($r = 0.95$) and at various FOVs ($r = 0.96$). The results indicate the reliability of the developed lidar system. [ABSTRACT FROM AUTHOR]

• The influence of wind-roughed sea surface on detection performance of spaceborne oceanic lidar, such as the recommended incident angles, and the inaccuracy of the signal depth, are studied using the spaceborne oceanic lidar radiative transfer model we developed. • The recommended incident angles for spaceborne oceanic lidar system are 35°∼37°, considering the lidar surface integrated attenuated backscatter. • The results show that the maximum possible error of detection depth is within 8.2% when the wind speed is below 15 m/s and the incident zenith angle is less than 30°, indicating that the spaceborne oceanic lidar enables to detect the global ocean effectively. The wind-roughed sea surface influences the propagation properties of the laser beam and consequently affects the detection accuracy of spaceborne oceanic lidar. A comprehensive analysis of this problem is lacking to date. Herein, the Cox and Munk surface model is applied to the spaceborne oceanic lidar radiative transfer emulator to solve this problem. The effects of wind-roughed sea surface on oceanic lidar laser pulse propagation properties, such as the deflection angle of the direction, the inaccuracy of the signal depth, and the recommended incident angles, are studied using this model. The relationships among the wind speed, the incident angle and the propagation properties of the laser beam when passing through the sea surface are established. The maximum possible error of detection depth is within 8.2% when the wind speed is below 15 m/s and the incident zenith angle is less than 30°. And it can be reduced to 1.8% by profile averaging, which reveals the spaceborne oceanic lidar is capable to detect the global ocean profile information effectively in windy conditions. Moreover, the recommended incident angles for an oceanic lidar system are 37° and 35°, when the effective reflectance of the whitecaps are 0.2 and 0.6, respectively. The conclusions of this paper have reference value for oceanic lidar remote sensing in practice. [ABSTRACT FROM AUTHOR]