Abstract
Hu and Yoshie (2020) proposed SER_C* (Stability Effect Ratio for Normalized pollutant concentration C*) as an index that expresses the stability effect on pollutant concentration. SER_C* represents the ratio of C* under non-neutral atmospheric stability conditions to that under neutral condition. They showed that the SER_C* increases with the Bulk Richardson number (Rb) in wind tunnel experiments. However, it is not clear to what extent the range of Rb in the wind tunnel experiments covers the range of Rb in real atmosphere. And the correspondence between Rb and the Pasquill atmospheric stability class is also unclear. To clarify these issues, in this study, we first calculated Rb in the real atmosphere using observed wind speed and air temperature data and ground surface temperature obtained by WRF analysis, and clarified the range and occurrence frequency of Rb, and correspondence between Rb and the Pasquill Atmospheric Stability Class. Next, we investigated the relationship between SER_C* and Rb in the real atmosphere by classifying NOx concentrations observed at air monitoring stations in Tokyo by Rb.
