Dimethyl sulfide in the Arctic atmosphere

Abstract

Dimethyl sulfide (DMS), sulfur dioxide, non‐sea‐salt sulfate, and various aerosol properties were measured during three field programs (two airborne and one ground‐based) near Barrow and Deadhorse (Prudhoe Bay), Alaska. The two airborne sampling programs took place in spring and early summer, and the ground‐based measurements spanned an entire summer. DMS concentrations in the Arctic atmosphere ranged from a few parts per trillion by volume (pptv) in spring and fall to higher values in summer (generally a few tens of pptv with occasional peaks of 100 to 300 pptv). In addition, DMS concentrations were measured during the spring near Resolute in seawater below the ice and in ice‐algae and kelp cultures. The seawater samples taken from below the ice in spring had DMS concentrations comparable to those in other oceanic regions. Taken together, these measurements show that the Arctic Ocean is potentially a substantial source of DMS, which likely becomes important as sea ice melts in the early summer. Local atmospheric concentrations increased throughout the summer, peaking in August. In regions where accumulation mode aerosols have been scavenged (e.g., by low‐level stratus clouds, which are common during the Arctic summer), evidence of rapid new particle production was observed. The seasonal cycle of atmospheric DMS closely resembles that of fine particles observed at Barrow, Alaska, and Alert, Northwest Territories, Canada. This finding indicates that DMS is likely an important precursor to the types of particles that dominate the background arctic aerosol in summertime. These results, together with those from several recently published studies of arctic aerosol, are combined to yield a consistent picture of the role of locally emitted DMS in the production of atmospheric aerosols in the Arctic in summer.

Changes in aerosol properties during spring-summer period in the Arctic troposphere

“…The levels of DMS may be largest in the latter part of the summer (Ferek et al, 1995), but the overall concentrations of SO 2 decrease over the investigated time period. Therefore there may be a debate about what process actually formed the SO 2 molecule; anthropogenic versus natural, and a biogenic source, via its sulphur cycle, cannot explain the transition.…”

“…The source of DMS is anticipated to be at its largest in late summer (August) according to study by (Ferek et al, 1995). They reported Arctic DMS concentration up to 300 ppt, while background concentrations stayed at a few tens of ppt.…”

“…Additional to the anthropogenic source it also has a natural biogenic source contributing to SO 2 in the atmosphere through oxidation of dimethyl sulphide (DMS) Ferek et al, 1995). We also explored measurements of CO and 210 Pb because in the Arctic the occurrence of these can be attributed exclusively to sources outside of the Arctic.…”

Impact of ocean acidification on Arctic phytoplankton blooms and dimethyl sulfide concentration under simulated ice-free and under-ice conditions

“…Due to various feedback processes, the atmospheric temperature in the Arctic region above 64 • N has warmed by 1.9 • C between 1981 and 2012, a rate 3 times higher than the global average (ACIA, 2005;Ford et al, 2015). This phe-nomenon, known as the Arctic amplification (Cohen et al, 2014), is leading to the greatest regional transformations observed in the recent decades (ACIA, 2005).…”

“…Once released to the atmosphere, DMS undergoes a rapid photochemical transformation into sulfate, which may result in an increase in the concentration of sulfate aerosols and cloud condensation nuclei. Emissions of DMS can thus increase cloud albedo and potentially cool the climate (Ferek et al, 1995;Quinn et al, 2002). The effect of DMS on climate is particularly important in regions of low aerosol burden, such as the summer Arctic atmosphere (Mungall et al, 2016).…”