Temporal and spatial variation of refractive index structure coefficient over South China sea

• Main Authors: Shiyong Shao, Fuqiang Qin, Manman Xu, Qing Liu, Yong Han, Ziqiang Xu
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: Results in Engineering
• Subjects: Optical turbulence; Refractive index structure coefficient; Temperature structure coefficient; Micro-thermometer; Radiosonde
• Online Access: http://www.sciencedirect.com/science/article/pii/S2590123020300992

Turbulence is a scientific problem that has not been solved completely for 300 years. Turbulence is brought out by buoyancy heat bubble and wind shear, which transports matter and energy between the earth’s surface and the atmosphere. Based on the data from the board measurement test through South China Sea Monsoon Experiment-II during June 2019, for the first time, the spatiotemporal distribution of optical turbulence over the South China sea and its sea surface is analyzed comprehensively. With distance to coast increasing, the ‘Sombrero’ structure turbulence diurnal feature of sea surface gradually disappears, finally close to a constant value 5×10−15m−2/3 after distance to land larger than 160 ​km. The optical turbulence strength and corresponding meteorological factors profiles are also managed. Generally, turbulence intensity decreases with height, but for the profile at 12:00, there are two reverse growth zone, one corresponding to the boundary layer and the other at about 16 ​km. For the profiles at 00:00, the strength of turbulence at all altitudes are weaker compared with profiles at 12:00, and the reverse growth zone in boundary layer disappears. The turbulence strength vertical distribution, expressed by simulation formula after statistical analysis, is affected by several factors but the outer scale is the most important one. Above summarized rule and formula will bring simplified way to calculation of turbulence effect over sea, and maybe provides the assistance for the equipment to laser atmospheric transmission applied in marine environment and estimation of material/energy transport between sea surface and atmosphere.