Ground-based synchronous optical instrument for measuring atmospheric visibility and turbulence intensity: theories, design and experiments.

Atmospheric visibility and turbulence are important meteorological factors in light propagation and optical communication, air quality prediction, and climate environment model. They are often measured separately by the conventional instruments, but the interaction between aerosol (closely relate to visibility) and turbulence may potentially influence their measurement accuracy. In this paper, a novel instrument, the atmospheric visibility and turbulence optical meter (AVTOM), is developed to synchronously measure atmospheric visibility and turbulence intensity through a transmission method. The atmospheric visibility is measured by the extinction principle whereas the turbulence intensity is measured by the light intensity flicker principle. We validated the measurement results by comparing them to other two conventional instruments in July 2017, at Nanjing, in southeast China. They agree well with the relative differences of 4.7% for the visibility and 3.5% for the turbulence intensity, respectively. We further demonstrated their dynamic changes under the different weather or aerosol loadings through the synchronous measurements, which may be associated with the aerosol-turbulence-interaction. Finally, we proposed a calibration method and discussed the measurement errors.