Northern and southern hemisphere ground-based infrared spectroscopic measurements of tropospheric carbon monoxide and ethane

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/98JD02515· OSTI ID:678838

Rinsland, Curtis P ^[1]; Murcray, Frank J; Mahieu, Emmanuel; Demoulin, Philippe ^[2]

---

1. Atmospheric Sciences Division, NASA Langley Research Center, Hampton, Virginia (United States)
2. Institute of Astrophysics and Geophysics, University of Liege, Liege-Cointe (Belgium)

Time series of CO and C{sub 2}H{sub 6} measurements have been derived from high-resolution infrared solar spectra recorded in Lauder, New Zealand (45.0&hthinsp;{degree}S, 169.7&hthinsp;{degree}E, altitude 0.37 km), and at the U.S. National Solar Observatory (31.9&hthinsp;{degree}N, 111.6&hthinsp;{degree}W, altitude 2.09 km) on Kitt Peak. Lauder observations were obtained between July 1993 and November 1997, while the Kitt Peak measurements were recorded between May 1977 and December 1997. Both databases were analyzed with spectroscopic parameters that included significant improvements for C{sub 2}H{sub 6} relative to previous studies. Target CO and C{sub 2}H{sub 6} lines were selected to achieve similar vertical samplings based on averaging kernels. These calculations show that partial columns from layers extending from the surface to the mean tropopause and from the mean tropopause to 100 km are nearly independent. Retrievals based on a semiempirical application of the Rodgers optimal estimation technique are reported for the lower layer, which has a broad maximum in sensitivity in the upper troposphere. The Lauder CO and C{sub 2}H{sub 6} partial columns exhibit highly asymmetrical seasonal cycles with minima in austral autumn and sharp peaks in austral spring. The spring maxima are the result of tropical biomass burning emissions followed by deep convective vertical transport to the upper troposphere and long-range horizontal transport. Significant year-to-year variations are observed for both CO and C{sub 2}H{sub 6}, but the measured trends, (+0.37{plus_minus}0.57){percent}&hthinsp;yr{sup {minus}1} and ({minus}0.64{plus_minus}0.79){percent}&hthinsp;yr{sup {minus}1}, 1 sigma, respectively, indicate no significant long-term changes. The Kitt Peak data also exhibit CO and C{sub 2}H{sub 6} seasonal variations in the lower layer with trends equal to ({minus}0.27{plus_minus}0.17){percent}&hthinsp;yr{sup {minus}1} and ({minus}1.20{plus_minus}0.35){percent}&hthinsp;yr{sup {minus}1}, 1 sigma, respectively. Hence a decrease in the Kitt Peak tropospheric C{sub 2}H{sub 6} column has been detected, though the CO trend is not significant. Both measurement sets are compared with previous observations, reported trends, and three-dimensional model calculations. {copyright} 1998 American Geophysical Union

• OSTI ID: 678838
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: D21 Vol. 103; ISSN 0148-0227; ISSN JGREA2
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
ATMOSPHERIC CHEMISTRY
CARBON COMPOUNDS
CARBON MONOXIDE
COMBUSTION
DIRECT SOLAR RADIATION
EMISSION
ETHANE
INFRARED SPECTRA
NORTHERN HEMISPHERE
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SEASONAL VARIATIONS
SOUTHERN HEMISPHERE
TROPOSPHERE