Correlation of free-space optics link attenuation with sonic temperature

Abstract

Our correlation analysis has shown promising and surprisingly good dependence of optical signal attenuation on sonic temperature, which is shown and discussed in this study. This discovered dependence is derived from measurements (periods with fog and rain events were excluded) and presented in the form of scatter plots. It is possible to express roughly that the attenuation decreases with the sonic temperature (negative correlation coefficient). Trying to understand our results, we added the explanation of the physical quantity sonic temperature in this contribution.

Different atmospheric effects causing FSO link attenuation: experimental results and modelling in Czech Republic

“…The high correlation between the sonic temperature and FSO link attenuation at "clear weather" conditions was discovered in [12]. Example of our measurement proving this is illustrated in Fig.10 (consider that the attenuation is inversely proportional to the temperature).…”

“…The sonic temperature T s is defined as [13]: (13) where t is the temperature in Celsius. For the clear air attenuation next approximation was derived from measurement [12]: One can see that the "clear attenuation" depends on the temperature, relative air humidity and air pressure. But the mathematical analysis showed that the attenuation is practically independent on the air pressure and the dependence on the relative humidity is weak.…”

FSO link attenuation measurement in extreme winter conditions for secure 5G applications

“…3, the path losses τ a that are obtained using (4) from the empirical formulas by Chladova et.al. 20 are also presented for comparison. In their work, for similar scenarios, the impact of temperature on the attenuation is quite significant and lowered temperature levels increase the attenuation.…”

“…It is found that the attenuation of the FSO link correlates quite well with the sonic temperature measured by acoustic anemometers. 20 They calculated the sonic temperature from atmospheric pressure, temperature, and relative humidity and found a good correlation between calculated and measured sonic temperature, and meteorological temperature. Thus, the modified sonic temperature expresses the attenuation in the FSO link 21…”