Seasonal cycles dominate the multiscale co-variability of dimethyl sulfide and precipitation

Dimethyl sulfide (DMS) is a major natural source of marine cloud condensation nuclei (CCN), yet whether its variability leaves a detectable imprint on precipitation remains unclear. Using a new dataset of two decades of daily global DMS fields reconstructed from satellite observations, we found DMS–precipitation co-variability across extensive but regionally patchy ocean sectors. The dominance of the annual cycle indicates that much of the observed DMS–precipitation co-variability is embedded within large-scale climatic forcing common to both fields. While the sub-seasonal signal carries negligible power at these scales, interannual coherence is regionally confined. Removing the seasonal cycle makes this explicit: once field significance is enforced, annual coherence survives in key parts of the ocean. Those are the regions where DMS and precipitation seem to co-vary beyond their common seasonality. By identifying where and when coherence actually emerges, this study provides a quantifiable scale-resolved candidate diagnostic for evaluating marine aerosol–cloud interactions in Earth System Models, which we argue is the way forward to elucidate the physics of the problem.