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

Abstract

Abstract. Time series of CO and C2H6 measurements have been derived from highresolution infrared solar spectra recorded in Lauder, New Zealand (45.0øS, 169.7øE, altitude 0.37 km), and at the U.S. National Solar Observatory (31.9øN, 111.6øW, 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 C2H 6 relative to previous studies. Target CO and C2H 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 C2H 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 Nadir-viewing infrared measurements of CO were obtained from the U.S. space shuttle in

Latitudinal variations of trace gas concentrations in the free troposphere measured by solar absorption spectroscopy during a ship cruise

“…SFIT2 [Pougatchev et al, 1995;Rinsland et al, 1998a] has been developed as a profile retrieval algorithm. It is based on the semiempirical approach to the optimal estimation method [Rodgers e!…”

Ground‐based measurements of tropospheric CO, C2H6, and HCN from Australia at 34°S latitude during 1997–1998

“…Vertical layer thickness in the forward model increases from less than 1 km in the first layer Microwindows and interfering molecules are listed in Table 1. The two windows adopted for the CO analysis and the single window for the C2H 6 retrievals are the same ones as used in a previous study of solar spectra recorded from several stations [Rinsland et al, 1998a[Rinsland et al, , 1999.…”

“…The analysis followed procedures adopted in previous studies [Rinsland et al, 1998a[Rinsland et al, , 1999[Rinsland et al, , 2001] with each parameter offset by its 1-sigma uncertainty for one or more typical cases to quantify the errors.…”

Trace gas emissions from biomass burning inferred from aerosol optical depth

“…Spectra were recorded in a number of regions of the infrared from 700 cm À1 to 4500 cm À1 using Mercury Cadmium Telluride and Indium Antimonide detectors, and a series of eight different optical band pass filters [Griffith et al, 1998]. The number of molecules per square centimetre above the measurement site (the vertical column amounts) of carbon monoxide (CO), ammonia (NH 3 ), formaldehyde (H 2 CO) and hydrogen cyanide (HCN) were derived from individual spectra from the appropriate filter regions, using the iterative fitting algorithm known as SFIT2 [Rinsland et al, 1998]. In this study the concentration profiles used for the initial simulation were typical of ''clean air'' and the analysis was weighted to allow very large variability in the boundary layer and lower troposphere to achieve a good fit.…”