Due to the space and time constraints of turbulence measurement equipment and test scene, it is difficult to obtain the refractive index structure constant of the atmosphere over the offshore. In this paper, the statistical characteristics of atmospheric optical turbulence over the offshore are summarized by analyzing the meteorological data. Within the reaching height of the sounding ball, most of the wind shear is within 0.016 s-1 from the 1km up to 15 km, and exceed 0.016 s-1 above 15km. Also, the values of temperature gradient are less than 0 km-1 from the ground to 15 km, and more than 0 km1 above 15km. The turbulent energy dissipation rate, potential refractive index gradient and outer scale peaks correspond to the up troposphere with altitudes around 13 km. Moreover, the mean values of coherence length, seeing, isoplanatic angle and coherence time from radiosonde measurement respectively are 4.15cm, 1.82arcsec, 0.24arcsec and 0.84ms over the offshore. The mean measurement result of seeing is generally greater than the night-time value of other observation sites. It is of great significance to research the turbulent characteristics of ocean atmosphere for optical transmission and astronomical observations.
This paper present the diurnal and seasonal variation of Turbulence Kinetic Energy (TKE) dissipation rate ( Ε ) in the Atmospheric Boundary-Layer (ABL) in Hefei area. Doppler spectrum width of wind profiler radar are used to separate the non-turbulent spectral width from the observed spectrum width and estimate ε .It is found that in the lower tropospheric height ε is in the range from 10-6 to 10-3 m2 s-3 . ε showed significant diurnal variation in the boundary-layer, with a smaller value at night and a larger value during the day, and the maximum value 10-3 m2 s-3 appears at the top of the ABL during the daytime. The diurnal variation of ε can be used to demonstrate the change of the boundary-layer height in Hefei area. The boundary-layer height begins to rise after sunrise and reaches the maximum at noon, about 1200 m. The parameter ε also shows significant seasonal variation. The ε and height of boundary-layer increased gradually since spring, reaching a maximum of about 1.3km in autumn and decreasing to the same level as in spring in winter. Because it is not affected by water vapor and temperature, ε from the data inversion of wind profile radar can describe turbulence information more accurately, and the results provide help for the study of matter and energy exchange between earth and air in Hefei area and laser atmospheric transmission etc.
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