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Full-Text Articles in Life Sciences
Long-Term Tropospheric Formaldehyde Concentrations Deduced From Ground-Based Fourier Transform Solar Infrared Measurements, Nicholas B. Jones, K Riedel, Barbara M. Allen, S. W. Wood, Paul Palmer, K Chance, Justus Notholt
Long-Term Tropospheric Formaldehyde Concentrations Deduced From Ground-Based Fourier Transform Solar Infrared Measurements, Nicholas B. Jones, K Riedel, Barbara M. Allen, S. W. Wood, Paul Palmer, K Chance, Justus Notholt
Faculty of Science - Papers (Archive)
We report a 13-year (1992–2005) dataset of total column measurements of formaldehyde (HCHO) over Lauder, New Zealand, inferred from solar infrared spectra measured using a high-resolution Fourier Transform Spectrometer (FTS). Ambient HCHO concentrations at this rural location are often close to levels typical of remote marine environments (<250 ppt), which are close to the detection limit using standard techniques. Consequently we develop a new method that successfully produces HCHO columns with sufficient sensitivity throughout the whole season. HCHO columns over Lauder have a strong seasonal cycle (±50%), with a mean column of 4.9×1015 molecules cm−2, peaking during summer months. A simple box model of CH4 oxidation reproduces the observed broad-scale seasonal cycle, but significantly underestimates the seasonal peak HCHO ground concentrations during summer. This suggests the existence of an additional significant source of HCHO, possibly isoprene that cannot be explained by oxidation of CH4 alone. The ground-based FTS column data compare well with collocated HCHO column measurements from the Global Ozone Monitoring Experiment (GOME) satellite instrument during the operational period of GOME (1996–2001, r2=0.65, mean bias=10%, n=48).
Ground-Based Solar Absorption Ftir Spectroscopy: Characterization Of Retrievals And First Results From A Novel Optical Design Instrument At A New Ndacc Complementary Station, Aldona Waiacek, J R. Taylor, K Strong, R Saari, T Kertzenmacher, Nicholas B. Jones, David W. Griffith
Ground-Based Solar Absorption Ftir Spectroscopy: Characterization Of Retrievals And First Results From A Novel Optical Design Instrument At A New Ndacc Complementary Station, Aldona Waiacek, J R. Taylor, K Strong, R Saari, T Kertzenmacher, Nicholas B. Jones, David W. Griffith
Faculty of Science - Papers (Archive)
The authors describe the optical design of a high-resolution Fourier Transform Spectrometer (FTS), which serves as the primary instrument at the University of Toronto Atmospheric Observatory (TAO). The FTS is dedicated to ground-based infrared solar absorption atmospheric measurements from Toronto, Ontario, Canada. Instrument performance is discussed in terms of instrumental line shape (ILS) and phase error and modulation efficiency as a function of optical path difference. Typical measurement parameters are presented together with retrieval parameters used to derive total and partial column concentrations of ozone. Retrievals at TAO employ the optimal estimation method (OEM), and some impacts of the necessary …