Atmospheric sulfur dioxide at Mauna Loa, Hawaii

Abstract

Measurements of sulfur dioxide (S02) were made at the National Oceanic and Atmospheric Administration's Mauna Loa Observatory in Hawaii, during a 12‐month period beginning in December 1988. SO2 concentrations varied from background levels of less than 0.05 ppbv to a maximum of 50 ppbv, during episodes that lasted from 2 to 24 hours. Emissions from the Kilauea crater, approximately 35 km southeast of the observatory at an elevation of about 1000 m above sea level (asl), and the current eruption at Puu O′o 50 km east‐southeast, are the most likely sources for the higher concentrations. These episodes occurred 10–25 times each month, mostly during the day; peak concentrations were usually recorded at mid‐day. The SO2 concentrations can be grouped into three periods; low (June–September), high (October–January) and intermediate (February–May). A clear diurnal cycle of SO2 concentration exists throughout the year, although day‐night changes were greatest during October–January and were barely detectable during the June–September period. The highest SO2 concentrations were recorded when the predominant wind direction was northerly to northwesterly, even though the apparent sources are in the southeastern sector. Nighttime concentrations were usually at background levels; however, many exceptions were observed. A few cases of higher than background SO2 were observed when free tropospheric (FT) conditions were identified. The possibility that long‐range transport was the cause for elevated SO2 concentrations under FT conditions was examined using air mass back trajectories analyses. The highest nighttime SO2 concentrations, under FT conditions, were observed during periods with slow easterly trajectories, and the lowest concentrations were found during westerly flows. Twenty‐four nighttime free tropospheric events were recorded when the SO2 concentration exceeded 0.2 ppbv. During 18 of these episodes, unusually high CO2 concentrations were observed.

Evaluation of a commercial pulsed fluorescence detector for the measurement of low‐level SO2 concentrations during the Gas‐Phase Sulfur Intercomparison Experiment

“…This agrees we!! with detection limits of 3040 pptv estimated by Luria et al [ 1990;1992] ............................................................................................................................. time among the four techniques contribute to the scatter evident in Figure 5. Nonetheless, the degree of agreement, especially toward the end of the sampling interval, is quite good.…”

A review of atmospheric chemistry observations at mountain sites

“…The red shaded bands and error bars denote the standard deviations. The concentrations of NO x and NO y were measured using photolytic (a-e), thermal Au (f-j), and Mo (k) convertors, followed by chemiluminescence detection Wang et al 2006;Xue et al 2011Xue et al , 2013Zhang et al 2009aZhang et al , 2011, HPO Pochanart et al 2004;Sharma et al 2000;Tanimoto 2009;Tanimoto et al 2009), FWS (Igarashi et al 2004(Igarashi et al , 2006, MLO (Brasseur et al 1996;Jaffe et al 1997;Levy and Moxim 1989;Luria et al 1992;Perry et al 1999), LAV (Jaffe et al 2003a), and MBO (Ambrose et al 2011;Fischer et al 2010a, b;Genualdi et al 2009;Jaffe et al 2005;Primbs et al 2008a, b;Reidmiller et al 2009Reidmiller et al , 2010Strode et al 2008;Swartzendruber et al 2006;Timonen et al 2013;Weiss-Penzias et al 2006Wolfe et al 2007). These emissions are illustrated in Fig.…”

Total reactive oxidized nitrogen (NOy) in the remote Pacific troposphere and its correlation with O3 and CO: Mauna Loa Observatory Photochemistry Experiment 1988

“…The small NO to SO2 ratio suggests only little if any impact of volcanic emissions on the downslope NOy measurements at MLO. Taking the NO to SO2 ratio from Bandy et al[1982] and the highest SO2 mixing ratio measured at MLO byLuria et al [1992] (45 ppbv) the contribution from the vents could be as large as 60 pptv or 22% of the median NOy value in free tropospheric air. Most of the time though the impact would be much lower since the vents are not always active.Nevertheless, it should be possible to detect such a correlation because of the high precision in the NOy data.…”