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2007

Life Sciences

Faculty of Science - Papers (Archive)

Fourier

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

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 Jan 2007

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).


Annual Variation Of Strato-Mesospheric Carbon Monoxide Measured By Ground-Based Fourier Transform Infrared Spectrometry, Voltaire A. Velazco, S.J. Wood, M Sinnhuber, I Kramer, Nicholas B. Jones, Y Kasai, Justus Notholt, Thorsten Warneke, T Blumenstock, F Hase, F Murcray, O Schrems Jan 2007

Annual Variation Of Strato-Mesospheric Carbon Monoxide Measured By Ground-Based Fourier Transform Infrared Spectrometry, Voltaire A. Velazco, S.J. Wood, M Sinnhuber, I Kramer, Nicholas B. Jones, Y Kasai, Justus Notholt, Thorsten Warneke, T Blumenstock, F Hase, F Murcray, O Schrems

Faculty of Science - Papers (Archive)

We present long-term time-series of strato-mesospheric CO vertical columns measured from stations located in Antarctica, mid-latitudes and the Arctic, covering the period from 19972005. The instrument and the measurement technique allows the separation of tropospheric and strato-mesospheric contributions to the CO column, therefore providing information on the chemistry and dynamics both at low and high altitudes. Data from polar stations show a similar annual variability of strato-mesospheric CO with a strong maximum in late winter and spring. A small enhancement in late summer for some stations, which we call the "summer bulge", can be seen occasionally. Generally, the mid-latitude stations …


Stratomesospheric Co Measured By A Ground-Based Fourier Transform Spectrometer Over Poker Flat, Alaska: Comparisons With Odin/Smr And A 2-D Model, Nicholas B. Jones, Y Kasai, E Dupuy, Y. Murayama, J Urban, B Barret, M Sinnhuber, A. Kagawa, T. Koshiro, P Ricaud, D Murtagh Jan 2007

Stratomesospheric Co Measured By A Ground-Based Fourier Transform Spectrometer Over Poker Flat, Alaska: Comparisons With Odin/Smr And A 2-D Model, Nicholas B. Jones, Y Kasai, E Dupuy, Y. Murayama, J Urban, B Barret, M Sinnhuber, A. Kagawa, T. Koshiro, P Ricaud, D Murtagh

Faculty of Science - Papers (Archive)

The interseasonal variability of stratomesospheric CO is reported from Poker Flat, Alaska, using spectra from a ground-based Fourier Transform Spectrometer (gb-FTS) for the time period from 2000 to 2004. The CO spectra were analyzed using an optimal estimation technique that separates the tropospheric and stratospheric/mesospheric components into partial columns. The distribution of CO in the polar winter is such that the gb-FTS retrieved partial column is weighted to the mesosphere. The gb-FTS data are compared with measurements of partial column CO from the Sub-Millimeter Radiometer on board the Odin satellite and shown to be in very good agreement despite the …