An anticyclonic point of view on low-level tropospheric long-range transport

Abstract

Research on Arctic haze has provided an example when anticyclones may play a dominant role in carrying out low-level tropospheric long-range transport. This dominant role of anticyclones in transporting Arctic haze may be the result of the unique geographic and climatological situation existing during winter/spring in which both the huge Eurasian continent and the adjacent ice-covered Arctic Ocean tend to be regions where anticyclones form and exist over long periods of the winter and spring seasons. It is assumed that the seasonal variation of transport mechanisms provided by anticyclones is the primary cause for the seasonal variation of Arctic haze. Centers of anticyclones are the regions where air masses form and obtain their characteristics, both meteorological and chemical, due to the aerosols and gases released into the air. Transport within an air flow along the edges of quasi-stationary anticyclones will remain under stable atmospheric conditions, hence, dilution, lifting and removal of aerosols and gases will be less compared to a transport within the influence of a cyclonic pressure system. According to the concept of isentropic flow, anticyclones may dominate only low-level transport, whereas cyclones may be more important in controlling transport at upper tropospheric levels.