[1] By means of a simple analytical one-dimensional (1-D) model, we predict mean vertical structure and fluctuations in trace gas concentrations as a function of species lifetime in the atmosphere. The model assumes a well-mixed planetary boundary layer (PBL) overlain by a free troposphere with constant diffusivity separated by a jump in species concentration. A jump in concentration is also as...

An intensive measurement campaign was performed in June 2000 at the Mt. Cimone station (4411’ N–1042’ E, 2165 m asl, the highest mountain in the northern Italian Apennines) to study photochemical ozone production in the lower free troposphere. In general, average mixing ratios of important trace gases were not very high (121 ± 20 ppbv CO, 0.284 ± 0.220 ppbv NOx, 1.15 ± 0.8 ppbv NOy, 58 ± 9 ppbv...

Landscape pattern (land use and natural patchiness) and complex topography strongly influence regional variation in emissions of trace gases and pollutants, as well as atmospheric transport processes. This leads to small-scale variation in the amount of (biogenic) emission, atmospheric deposition and in local concentrations of atmospheric consitutents. This chapter addresses the most important ...

The progress of technology has made the measurement of air quality and the simulation of complex air pollution models both feasible and cost-effective. However, there is a long way to go in terms of facilitating widespread access to the data and models, and linking the monitoring of trace gases with specific urban activities and land use that might be controllable. As part of a NASA-funded proj...

[1] The meteorological mechanisms for lofting trace gases and aerosols out of the planetary boundary layer (PBL) into the free troposphere are key to understanding local air pollution problems as well as regional and global atmospheric chemistry and climate issues. Over the North American continent, convective storms and lifting in warm conveyor belts transport pollutants into the free troposph...

Enhancing our understanding of atmospheric processes and transformations require a suite of ever more sensitive, selective, versatile, and fast instruments that can measure trace atmospheric constituents at and below mixing ratios of 100-parts-per-trillion on airborne platforms. Instruments that can carry out such measurements are very challenging, as airborne platforms vibrate, experience acce...

A liquid-nitrogen-cooled CO laser and an intracavity resonant photoacoustic cell are employed to monitor trace gases. The setup was designed to monitor trace gas emissions of biological samples on line. The arrangement offers the possibility to measure gases at the 10(9) by volume (ppbv) level (e.g., CH(4), H(2) O) and to detect rapid changes in trace gas emission. A detection limit of 1 ppbv f...

During SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) we performed measurements of a wide range of trace gases with different lifetimes and sink/source characteristics in the northern hemispheric upper troposphere (UT) and lowermost stratosphere (LMS). A large number of in-situ instruments were deployed on board a Learjet 35A, flying at altit...

Convective clouds and thunderstorms redistribute air pollutants vertically, and by altering the chemistry and radiative balance of the upper troposphere, these local actions can have global consequences. To study these effects, measurements of trace gases ozone, Os, carbon monoxide, CO, and odd nitrogen were made aboard the NCAR Sabreliner on 18 flights over the southern Great Plains during Jun...

The air-water exchange of trace gases such as CO is usually parameterized in terms a gas transfer velocity, which can be derived from direct measurements the air-sea flux. ve...