UC Merced

Carbonyl sulfide (OCS or COS) is the most common sulfur-containing species in the atmosphere and has the potential to function as a proxy for photosynthetic carbon uptake (gross primary productivity, GPP). In order to expand this technique to regional and global scales, additional questions about poorly constrained aspects of the carbonyl sulfide budget must be resolved.

The first section of this work is devoted to developing a new, spatially resolved and temporally varying inventory of carbonyl sulfide emissions from biomass burning. By leveraging long-term, in situ observations of atmospheric carbonyl sulfide, we demonstrate that biomass burning emissions are heavily dependent on biome and are not sufficient to close the overall flux budget.

The second section of this dissertation uses this biomass burning inventory in conjunction with a global chemical transport model in order to constrain plant fluxes in the Amazon basin. Using satellite data from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, I show that downstream observations of carbonyl sulfide in the upper troposphere retain useful information about surface processes and can provide an independent constraint on gross primary production given sufficient convective transport.

Finally, I conduct an observing system simulation experiment (OSSE) to investigate how future remote-sensing campaigns could yield more information and better constrain GPP using carbonyl sulfide. In addition to considering sampling density, sampling height and instrument noise in satellite observations, I address potential challenges in future aircraft sampling campaigns.