Biogenic Organic Aerosol Experiment in Amazonia

Harvard University, Cambridge MA

Investigators

Abstract

During the wet season, the Amazon rainforest is a largely unperturbed system with respect to the formation of accumulation mode biogenic aerosols. This study will further describe the formation, processing and cloud forming properties of natural secondary organic aerosols (SOA) in a pristine setting. Arising from the photoreaction of vegetative emissions (e.g., isoprene, monoterpenes) and atmospheric oxidants, the size resolved particulate evolution of SOA into larger, cloud condensation nuclei (CCN) potentially serves as a mechanistic link between biological processes and climate through resulting control of precipitation patterns. Field investigations will take advantage of an existing forest research site, the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) tower site located 60km north of Manaus, a city of approximately 2 million and the capital of Amazonas state, Brazil. The prime experimental strategy will concentrate on the deployment of a high (mass) resolution time-of-flight aerosol mass spectrometer (HR ToF-AMS) which will allow the atmospheric mass loading, the mass spectra (chemical identification) and the aerodynamic size distribution (35nm to 1.5um) of SOA particles to be observed at high temporal resolution.