ANALYSES OF 7BE AND 210PB MEASUREMENTS WITH OZONE OBSERVATIONS AT GAW STATIONS

Ozone plays an important role in global climate change studies. It is an important greenhouse gas and its overall increase in concentration due to the anthropogenic activities is presently of great concern. The variability of surface ozone is affected by photochemical process in the troposphere and by stratosphere-to-troposphere exchange process. The interpretation of high surface ozone concentrations is very complex, since these two processes that are different may interfere with one another. Simultaneous measurements and analyses of 210Pb and 7Be can provide useful information about the movement of air flow in the atmosphere (Lee et al., 2004). For example, high 7Be concentrations with respect to low 210Pb concentrations detected at the surface station could indicate a strong subsidence of air from upper altitudes that would increase surface 7Be, since 7Be is mainly produced in the upper troposphere and lower stratosphere. On the other side, ozone produced within polluted air masses at the Earth’s surface can be traced by 210Pb, a radiotracer in a lower troposphere, produced by the decay of 222Rn exhaled in the earth’s crust. The analyses of variances of 210Pb and 7Be measurements, hopefully, will help in deeper understanding the changes and transport processes of ozone that are occurring in the atmosphere. The measurements of concentrations of natural radionuclides, which become irreversibly attached to nonreactive submicron aerosol particles, have been widely used by atmospheric scientists for global model validation (e.g., Josse et al., 2004; Lee, 2003; Lee and Feichter, 1995). Researchers have found 210Pb and 7Be to be useful natural tracers for studying atmospheric circulation, transport and mixing processes, and deposition and removal processes involved in the models.