An investigation of the protential retrieval of peroxyacetyl nitrate from the MIPAS spectral dataset
Abstract
Peroxyacetyl nitrate (PAN) is a chemically important atmospheric trace species through its role as a reservoir species for NOx, mediating its transport and hence the influence of NOx on ozone chemistry and the oxidising power of the atmosphere. Current understanding of the gas is limited to sparse in situ process studies conducted during aircraft campaigns chiefly in the northern hemisphere lower troposphere region. Observations of PAN in the upper troposphere are particularly limited. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-viewing Fourier transform infrared spectrometer launched onboard the ESA Envisat satellite in March 2002. The MIPAS infrared spectral dataset has been designed to be a valuable resource for the retrieval of trace gas concentrations in the nominal altitude range (6-68 km) with pole-to-pole global coverage. The high spectral resolution of MIPAS (0.025 cm^-^1 unapodised) offers particular promise for the detection of less abundant trace species since such lines may be distinguished from within the high density of spectral lines of major constituents such as CO_2, O_3 and H_2O. In particular, the high spectral resolution offers promise for new measurements of PAN in the upper troposphere whilst allowing cloud effects to be flagged and removed. The retrieval of trace gas data from spectral measurements requires accurate laboratory spectral information for the target gas under ambient conditions appropriate to the region of study. Future measurements will be made at 190K with air broadening to 200mb as typified by the upper troposphere. Preliminary spectroscopic results to this end will be presented for peroxyacetyl nitrate and the potential for the retrieval of atmospheric profiles of the species using MIPAS will be discussed.
- Publication:
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EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....5546A