Science and technology of atmospheric effects on optical engineering: Progress in 3rd quinquennium of 21st century

Rao, Ruizhong

doi:10.1007/s11431-017-9049-6

Cited by 3 publications

(1 citation statement)

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“…Temperature gradient of day is more intensive than that of night. For turbulence above 14 2/3 10 m  , there are similar response to ultrasonic anemometer and micro-thermometer, but microthermometer with higher sensitivity for turbulence under To verify the reliability of diurnal variation of measurement data, the other representative day, 17 Oct., is selected. The turbulence strength in Fig.6(a), no matter from ultrasonic anemometer or micro-thermometer, is generally stronger and smoother than that of 26 Sep., but conversion times are vague.…”

Section: B Instrument Calibration and Comparisonmentioning

confidence: 99%

Turbulent Structure Function Analysis Using Wireless Micro-Thermometer

Shao¹,

Qin

Liu

et al. 2020

IEEE Access

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Most of the application scenarios of techniques related to electromagnetic wave transmission of photoelectric system are located in the earth's atmosphere or through the atmospheric path. The electromagnetic wave will change state through the atmosphere when encounters the inhomogeneities of refractive index caused by turbulence. Optical turbulence causes degradation of beam quality and energy to laser transmission, and brings image deterioration to astronomical observation. The refractive index structure coefficient is an important parameter describing the turbulence strength. For visible and near infrared band, the refractive index structure coefficient mainly depends on temperature structure coefficient. Using the theory of Wheatstone bridge, the micro-thermometer is designed and self-developed. To avoid interference from human and buildings, the wireless control for the micro-thermometer is realized based on CC1100. The observation of turbulence strength of representative test point, for more than one month, is implemented at Yangmeikeng near the South China Sea. Compared to ultrasonic anemometer, there is a sensitive lower measurement limit of micro-thermometer whose effective refractive index structure coefficient of system noise is less than 18 10  m-2/3. There is obvious 'Sombrero' structure diurnal variation of turbulence near South China Sea, whose strength is mainly brought out by buoyancy heat bubble in day, and by wind shear at night. Monin-Obukhov length is positive at night and negative in day, and the scaling exponent is near-5/3 for temperature power spectrum, which is similar to wind power spectrum except for periods when wind from inland. The diurnal variation and scaling exponent of power spectrum analysis indicate that the measurement range and the sample rate of micro-thermometer are enough to response the turbulence measurement encountered in most laser transmission and astronomical observation fields. The turbulence characteristics information gained from micro-thermometer measurement data analysis brings good reference to optimal design and operation for photoelectric system.

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Section: B Instrument Calibration and Comparisonmentioning

confidence: 99%