Ground-based FTIR spectrometer observation of nitrous oxide and its validation over addis ababa, Ethiopia

Samuel Takele, Gizaw Mengistu, Thomas Blumenstock, Frank Hase

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Since May 2009 high-resolution Fourier transform infrared (FTIR) solar absorption spectra are recorded at Addis Ababa (9.01o N, 38.76o E, 2443 m altitude above sea level) Ethiopia. The vertical distribution of nitrous oxide (N2O) was deduced from the spectra by using the retrieval code PROFFIT (V9.5). Four microwindows were taken for N2O in the range between 2481 to 2541 cm-1 and regularly determined instrumental line shape (ILS) was applied. A detailed error analysis of the N2O retrieval is performed. Averaging kernel of N2O indicates that there is sufficient information coming from the measurements, particularly at lower altitude. The variability of retrieved total column amount and profiles are observed over seasonal and inter-annual time scale. In spring season, the total column amount and volume mixing ratios (VMR) profiles of N2O have shown relative increase with respect to the other seasons. The short term variation of N2O profiles has also observed due to the transport process. A comparison of FTIR measurement of N2O vertical profiles are made with coincident measurements of MLS satellite. Between 15 to 33 km, the mean absolute differences for FTIR comparisons lie within a range of -0.048 ppmv to +0.028 ppmv, however, most frequent values are approximated to be within 0.027 ppmv. The mean relative differences are found to lie between +5.8 ppmv and -3.7 ppmv. This corresponds to relative deviation from the mean are ranging from 4.4% to 35.6%.
Original languageEnglish
Title of host publicationFourier Transform Spectroscopy, FTS 2011
PublisherOptical Society of America (OSA)
ISBN (Print)9781557529145
DOIs
Publication statusPublished - 2011
EventFourier Transform Spectroscopy, FTS 2011 - Toronto, Canada
Duration: Jul 10 2011Jul 14 2011

Publication series

NameOptics InfoBase Conference Papers
ISSN (Electronic)2162-2701

Other

OtherFourier Transform Spectroscopy, FTS 2011
CountryCanada
CityToronto
Period7/10/117/14/11

All Science Journal Classification (ASJC) codes

  • Instrumentation
  • Atomic and Molecular Physics, and Optics

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