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Fourier Transform Infrared (FTIR) spectrometry has been used for ground-based solar absorption, laboratory and flux measurements, to study the atmospheric composition, as well as physical and chemical processes in the atmosphere.The solar absorption FTIR measurements have been performed in Paramaribo, Suriname (5.8 N, 55.2 W) between September 2004 and November 2007 and represent the first remote sensing measurements in the inner tropics over severalyears. These measurements are of great importance for a better understanding of global climate and physical and chemical processes of the tropical atmosphere as well as for satellite validations. Vertical profiles of carbon monoxide (CO) and ethane (C2H6) and total columns of methane (CH4), hydrogen cyanide (HCN) and acetylene (C2H2) have been retrieved from the FTIR spectra. The quality of the methane retrieval was limited by the available spectroscopic data. Laboratory cell-based FTIR measurements have been performed to correct the methane spectroscopy in the infrared spectral region, which significantly improved the retrieval of methane from SCIAMACHY and FTIR spectra. The retrieval of methane profiles from near-infrared FTIR spectra by optimal estimation significantly improved the results. The FTIR observations of methane are compared with TM5 model simulations and satellite observations from SCIAMACHY, and are the first validation of the SCIAMACHY retrieval in the tropics using remote sensing techniques. The ratio CH4/CO2, which can be measured directly from SCIAMACHY and FTIR, compares very good, while the column averaged volume mixing ratio (XVMR(CH4)) of SCIAMACHY do not agree with the FTIR observations. Model assumptions areused in the SCIAMACHY retrieval to derive the XVMR(CH4) from the directly measured CH4/CO2 ratio. The worse agreement of SCIAMACHY XVMR(CH4) with FTIR compared to the SCIAMACHY CH4/CO2 ratio with FTIR could be attributed to unrealistic model assumptions used in the SCIAMACHY retrieval that le

Fourier Transform Infrared (FTIR) spectrometry has been used for ground-based solar absorption, laboratory and flux measurements, to study the atmospheric composition, as well as physical and chemical processes in the atmosphere.The solar absorption FTIR measurements have been performed in Paramaribo, Suriname (5.8 N, 55.2 W) between September 2004 and November 2007 and represent the first remote sensing measurements in the inner tropics over severalyears. These measurements are of great importance for a better understanding of global climate and physical and chemical processes of the tropical atmosphere as well as for satellite validations. Vertical profiles of carbon monoxide (CO) and ethane (C2H6) and total columns of methane (CH4), hydrogen cyanide (HCN) and acetylene (C2H2) have been retrieved from the FTIR spectra. The quality of the methane retrieval was limited by the available spectroscopic data. Laboratory cell-based FTIR measurements have been performed to correct the methane spectroscopy in the infrared spectral region, which significantly improved the retrieval of methane from SCIAMACHY and FTIR spectra. The retrieval of methane profiles from near-infrared FTIR spectra by optimal estimation significantly improved the results. The FTIR observations of methane are compared with TM5 model simulations and satellite observations from SCIAMACHY, and are the first validation of the SCIAMACHY retrieval in the tropics using remote sensing techniques. The ratio CH4/CO2, which can be measured directly from SCIAMACHY and FTIR, compares very good, while the column averaged volume mixing ratio (XVMR(CH4)) of SCIAMACHY do not agree with the FTIR observations. Model assumptions areused in the SCIAMACHY retrieval to derive the XVMR(CH4) from the directly measured CH4/CO2 ratio. The worse agreement of SCIAMACHY XVMR(CH4) with FTIR compared to the SCIAMACHY CH4/CO2 ratio with FTIR could be attributed to unrealistic model assumptions used in the SCIAMACHY retrieval that le

Fourier Transform Infrared (FTIR) spectrometry has been used for ground-based solar absorption, laboratory and flux measurements, to study the atmospheric composition, as well as physical and chemical processes in the atmosphere.The solar absorption FTIR measurements have been performed in Paramaribo, Suriname (5.8 N, 55.2 W) between September 2004 and November 2007 and represent the first remote sensing measurements in the inner tropics over severalyears. These measurements are of great importance for a better understanding of global climate and physical and chemical processes of the tropical atmosphere as well as for satellite validations. Vertical profiles of carbon monoxide (CO) and ethane (C2H6) and total columns of methane (CH4), hydrogen cyanide (HCN) and acetylene (C2H2) have been retrieved from the FTIR spectra. The quality of the methane retrieval was limited by the available spectroscopic data. Laboratory cell-based FTIR measurements have been performed to correct the methane spectroscopy in the infrared spectral region, which significantly improved the retrieval of methane from SCIAMACHY and FTIR spectra. The retrieval of methane profiles from near-infrared FTIR spectra by optimal estimation significantly improved the results. The FTIR observations of methane are compared with TM5 model simulations and satellite observations from SCIAMACHY, and are the first validation of the SCIAMACHY retrieval in the tropics using remote sensing techniques. The ratio CH4/CO2, which can be measured directly from SCIAMACHY and FTIR, compares very good, while the column averaged volume mixing ratio (XVMR(CH4)) of SCIAMACHY do not agree with the FTIR observations. Model assumptions areused in the SCIAMACHY retrieval to derive the XVMR(CH4) from the directly measured CH4/CO2 ratio. The worse agreement of SCIAMACHY XVMR(CH4) with FTIR compared to the SCIAMACHY CH4/CO2 ratio with FTIR could be attributed to unrealistic model assumptions used in the SCIAMACHY retrieval that le