Tropospheric carbonyl sulfide mass balance based on direct measurements of sulfur isotopes

Significance Assessment for large-scale photosynthesis-climate feedbacks is needed. Carbonyl sulfide (COS) an emerging proxy the terrestrial photosynthesis. This limited by uncertainties related to magnitudes of COS sources and sinks. Here, we demonstrate measurement-based assessments isotopic signal of: tropospheric COS, marine anthropogenic emissions, fractionation plant uptake. All these resulted in mass balance budget which gives important constraint its sources.