Drivers of Atmospheric DMS Variability over the Arabian Sea

Dimethyl sulfide (DMS) plays a critical role in atmospheric chemistry by contributing to the secondary sulfate aerosols and cloud formation in the remote marine atmosphere. A new study conducted by researchers from Physical Research Laboratory (PRL), Ahmedabad, India, used ship-borne measurements of atmospheric DMS over the Arabian Sea to investigate its relations with hydrographic parameters and atmospheric processes. The first-time measurements revealed significant spatio-temporal variations of DMS mixing ratio (20−709 ppt), with higher concentrations near the coastal regions (116±120 ppt) than over the oligotrophic open ocean (62±53 ppt). Although overall DMS increased with Chlorophyll-a, the regional variability patterns and enhancements were driven by sea surface temperature (SST), salinity gradients, and wind conditions. Continental outflow influenced the DMS-radical chemistry and short-term variability in the coastal regions. Results highlight complex controls of DMS emissions under different environmental conditions, relevant for chemistry-climate modelling.

Reference: Gupta, M., Sahu, L.K., Tripathi, N., et al. (2025). Processes controlling DMS variability in marine boundary layer of the Arabian Sea during post-monsoon season of 2021. J. Geophys. Res.: Atmos., 130(9), e2024JD042547. https://doi.org/10.1029/2024JD042547