Variations of Carbonyl Sulfide During the Dry/Wet Seasons Over the Amazon

Mid-tropospheric Carbonyl sulfide (OCS) retrievals from the Tropospheric Emission Spectrometer (TES) are utilized to study OCS distributions during the dry/wet seasons over the Amazon rainforest. TES OCS retrievals reveal positive OCS anomalies (similar to 16 ppt) over the central and southern parts of the Amazon during August-October (dry season) compared to January-March (wet season). There is less OCS taken up by vegetation and soil and more OCS released from biomass burning during the dry season, which causes an increase in OCS concentrations. Strong sinking air during the dry season also helps to trap OCS and this contributes to positive OCS anomalies. MOZART-4 model captures positive OCS anomalies over the central and southern regions of the Amazon and negative OCS anomalies over the northern part of the Amazon, which are similar to those from TES mid-tropospheric OCS retrievals. Our studies can help us better understand OCS variations and photosynthetic activities.