Air-sea coupling and energy circulation inside the ocean are the frontiers of ocean science and important directions of earth system science. Researchers have carried out extensive research on multi-scale dynamic characteristics and ecological environment parameters based on the development of advanced remote sensing technology. However, the lack of in-situ detection technologies for measuring marine micro-scale dynamic characteristics, and biological, physical, and chemical features restricts the study of micro-scale phenomena and biological optics inside the ocean. The development of these technologies for micro-scale turbulence and particle size distribution in the ocean mixing layer can improve the understanding of the energy and matter transport inside the ocean. We focus on the great demand for high-resolution in-situdetection technology during the study of micro-scale turbulent flow structure and analyze the feasibility of the laser Doppler current probe in micro-scale turbulence measurement. Finally, theoretical support is provided for achieving a non-contact measurement system with high spatio-temporal resolution.

Important specification parameters in the scheme design of the laser Doppler current meter system are analyzed theoretically. The technical parameters obtained by theoretical analysis and literature research directly contribute to device selection and data correction during system construction. Meanwhile, we analyze the factors affecting the signal-to-noise ratio of the laser Doppler current probe, including the laser wavelength, scattered light direction received by the optical system, size and concentration of scattered particles, power of the transmitting laser, velocity of the particles, and bandwidth of the signal acquisition system.

Suggestions on wavelength selection of laser source are provided by analyzing the absorption coefficient of lasers in different water media. The scattering signals of suspended particles are the main signal source of the laser Doppler current probe. The performance of the laser Doppler current probe system is affected by the physical characteristics of suspended particles (such as shape, particle size, and density), fluid characteristics, and motion state. Additionally, we conclude that the laser Doppler current meter system has enough signal source in most sea areas, and the parameter scheme of the laser Doppler current meter system can cover most particle sizes by investigating the particle size composition, particle size distribution, and concentration of suspended particles in the ocean. The dependence of suspended particles is simulated based on the Basset Boussinesq OSEEN (BBO) equation to correct the velocity errors at different angular frequencies and provides theoretical support for data correction.

The laser Doppler current probe has been proven to be effective in measuring ocean micro-scale turbulence based on a comprehensive analysis of relevant characteristics of ocean water and suspended particles. Suggestions and parameter calculation methods of the laser Doppler current probe system are discussed in the manuscript for micro-scale turbulence measurement.