Use of airborne radon measurements to recognize long range transport events in the mid and upper troposphere

摘要

The continuing increase in pollution sources and the resultant increase in the global abundance of pollutants such as sulfur dioxide, non-methane hydrocarbons, and other volatile organic compounds has led to a need to improve our understanding of the global-scale transport of these compounds. Radon, because of its surface source, short (3.8 day) half life, and immunity from removal by chemical or physical scavenging is ideally suited as a tracer for the long-range transport of many pollutants, and when measured from ships has been used for many years as an indicator of the movement of polluted continental air over the oceans. A detailed meteorological analysis, concluded in this study, was made for several air masses sampled aboard the NASA C-141 aircraft in order to establish the source and transport mechanism of radon-rich air observed on several occasions in the upper troposphere over the eastern Pacific Ocean. These analyses, which were incorporated in a manuscript and submitted for publication, showed that the radon-rich air sampled originated in the Asian boundary layer, ascended in cumulus updrafts, and was carried eastward in the fast moving polar jet stream, a mechanism consistent with the rapid longrange transport of many chemically active pollutant species as well.