Infrared solar spectroscopic measurements of free tropospheric CO, C₂H₆, and HCN above Mauna Loa, Hawaii: Seasonal variations and evidence for enhanced emissions from the Southeast Asian tropical fires of 1997–1998

Abstract

(1 ppbv = 10 -9 per unit volume), more than a factor of 3 above the background level.The HCN enhancements continued through the end of the observational series. Backtrajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H 6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong E1 Nifio warm phase of 1997-1998 are the likely source of the elevated emission products. IntroductionThe purpose of this paper is to report and interpret a time series of measurements derived from high-resolution (

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.…”

Seasonal variations of HCN over northern Japan measured by ground‐based infrared solar spectroscopy

“…The HCN measurements at the subtropical station of Mauna Loa Observatory (MLO) (20øN, 156øW, 3.4 km a.s.1.) also showed an enhancement up to a factor of 3 above the background level, most likely due to biomass burning [Rinsland et al, 1999]. Since at present there is very limited knowledge regarding the causes for seasonal variability in HCN, long-term observations at various locations could provide useful information on the temporal and spatial variations in HCN.…”

“…The difference between the artificial and retrieved HCN column amounts was 5%, which is defined as the error due to the algorithm as given in Table 1. The uncertainty in the HCN line parameters was estimated to be +2% [Rinsland et al, 1999]. Assuming 0.3% as the maximum RMS noise in HCN spectra and +5øC uncertainty in the temperature measurements, random errors due to these two parameters were calculated and are listed in Table 1.…”

Five years of CO, HCN, C<sub>2</sub>H<sub>6</sub>, C<sub>2</sub>H<sub>2</sub>, CH<sub>3</sub>OH, HCOOH and H<sub>2</sub>CO total columns measured in the Canadian high Arctic

“…CO, HCN, C 2 H 6 and C 2 H 2 total and partial columns have been measured by ground-based FTIR spectroscopy at several locations in the Northern Hemisphere (Mahieu et al, 1997;Rinsland et al, , 2000Zhao et al, 2002) and in the Southern Hemisphere (Rinsland et al, 1999(Rinsland et al, , 2001Paton-Walsh et al, 2010;Vigouroux et al, 2012). CH 3 OH and HCOOH have been measured in a limited number of ground-based FTIR studies (Paton-Walsh et al, 2005Rinsland et al, , 2009Zander et al, 2010;Paulot et al, 2011).…”