Current Atmospheric Chemistry Laboratory Studies:
Chemical Kinetics and Photochemistry
The JPL laboratory kinetics group measures the rate of many reactions on the surface of aerosols, clouds, and in the gas phase that are relevant to our understanding of stratospheric and tropospheric ozone. The group uses measurement techniques such as discharge-flow, flash-photolysis and laser-photolysis, mass spectrometry, and laser resonance fluorescence. Several members of this group are members of the NASA Panel for Data Evaluation, which publishes approximately every two years a document entitled "Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling." This document provides a comprehensive review of the kinetics literature since the last evaluation and makes recommendations regarding the reaction rates and absorption cross sections that should be used for quantitative studies of ozone.
The JPL Infrared Spectroscopy Group measures
line positions and strengths as well as pressure broadening coefficients of many
molecular species that are of atmospheric interest. This data is critical for
both in situ and remote measurements of many gases by instruments built at JPL
and at many other institutes. Spectroscopic features are also used to gain
insight into the fundamental structure of molecules. Most infrared spectroscopic
measurements are made using the McMath Fourier Transform spectrometer housed at
the Kitt Peak National Observatory in Tucson, Arizona. The Kitt Peak facility is
operated by the National Solar Observatory (NSO), which is a division of the
National Optical Astronomy Observatories (NOAO). Measurements of short-lived
radical species are made at JPL using a high resolution Bomem Fourier Transform
JPL spectroscopists also compile and merge databases from different investigators in order to make comprehensive electronic data records for inclusion into the widely used HITRAN (High Resolution Transmission) database. The construction of electronic databases is a critical part of the analysis of data from remote sensing instruments such as those onboard the NASA EOS (Earth Observing System) and UARS (Upper Atmospheric Research Satellite) satellites.
Microwave and Submillimeter Wave Spectroscopy
The JPL Microwave Spectroscopy Group provides millimeter and submillimeter frequencies, linewidths and transition moments of upper atmospheric species either being sought by the various observing programs or having the potential of being observed by instrumentation under development by NASA. It directly supports the UARS and MLS programs. It also supports the development of submillimeter radiometers such as the one proposed for EOS and provides useful spectroscopic parameters to the infrared spectroscopy programs. There is a continuing collaboration with the chemical kinetics task that is directed toward identification of transient halogen oxide and halo-acid species and the determination of their structures.
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Author: Randall R. Friedl
Page Design: Aaron Milam