Small air ion statistics near the earth's surface

Abstract

The development of an atmospheric electricity-monitoring network stimulates research into the relationship between the global electrical circuit and environmental conditions. Small air ions in the lower atmosphere are the main carriers of the conduction current and, at the same time, are themselves carried by atmospheric turbulence. However, it is not clear to what extent the statistics of fluctuations in the concentration of small ions in the electrode layer adjacent to the earth's surface bears the features of scalar turbulence. Based on field experiment data, the probability density functions of fluctuations of both the concentration of small ions and temperature are found to be non-Gaussian and approximated by a stable distribution model with the index of stability α in the range from 1.1 to 1.96. Observations have demonstrated that statistics of temperature fluctuations is more intermittent, compared to height-dependent statistics of fluctuations of the concentration of small ions. It is found that the autocorrelation function and second-order structure function have different behavior for the concentration of small ions and temperature in the time range 1–50 s.