Environmental Molecular Sciences Laboratory

A DOE Office of Science User Facility

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GOAmazon and EMSL

OVERVIEW

Green Ocean Amazon, or GOAmazon, is an integrated experiment to look at the coupled atmosphere-cloud-terrestrial tropical systems in the Amazon Basin. The Department of Energy's Office of Biological and Environmental Research's Climate and Environmental Sciences Division, in collaboration with Brazilian and German organizations, will lead GOAmazon.

The GOAmazon campaign seeks to quantify and understand how aerosol and cloud life cycles in a particularly clean background in the tropics are influenced by pollutant outflow from a large tropical city. The GOAmazon campaign addresses the susceptibility of cloud-aerosol-precipitation interactions to present-day and future pollution in the tropics. In particular, the second year of measurements will enable comparative year-to-year variability in the measurements and will be an important step forward in knowledge about inter-annual differences in the Amazon Basin and their effects of atmospheric and ecosystem functioning.

GOAmazon will run through the wet and dry seasons from January 2014 to December 2015.

Science Focus

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EMSL Engineer Matt Newburn adjusts the high resolution time-of-flight aerosol mass spectrometry, or H-ToF-AMS.[/caption]

The project's first objective is to understand and quantify the interactions of biogenic and anthropogenic emissions in the production of secondary organic aerosol, or SOA. In clean conditions in the Amazon Basin, SOA represents the dominant mass fraction particles below one micron in diameter.

The second objective follows from the first in that, although submicron particle mass is dominated by SOA, the actual source of new particle production remains uncertain. The second objective is to test the hypothesis that new particles under natural conditions are produced as a result of evaporation of primary particles emitted by fungal spores as well as to investigate any shifts in this mechanism under pollution conditions, such as a consequence to the high concentrations of sulfur dioxide in the pollution plume. Combined, the number-diameter distribution is the key connection to upscaling to the effects of aerosol particles on clouds and climate.

The third objective seeks to understand this upscaling under clean and pollution conditions, including differences.

EMSL's role

EMSL will provide its high resolution time-of-flight aerosol mass spectrometry, or H-ToF-AMS, capability for the field campaign and associated user facility support by EMSL scientific staff for the entire year of 2014, focused on addressing the campaign’s first and second objectives. EMSL will also support the detailed analysis of the data from the campaign during 2015.

The H-ToF-AMS quantitatively measures the size and chemical composition of volatile/semi-volatile submicron aerosols. It is designed to provide quantitative composition information on ensembles of particles. The deployment of the EMSL H-ToF-AMS will provide an unprecedented continuous data set of size and composition of aerosol particles produced over the range of conditions represented by on annual cycle.

During two key intensive eight-week periods – one in the spring and another in the fall – the EMSL H-ToF-AMS will be used to further characterize aerosol production in both the wet and dry seasons. The AMS will be operated in conjunction with professors Scot Martin of Harvard and Professor Jose Jimenez of the University of Colorado, Boulder, with special front-end sampling equipment to determine not only existing SOA but the potential aerosol mass obtained by subjecting part of the sample air to oxidizing conditions found in the rain forest atmosphere, thereby providing a good measure of the final distribution of SOA downwind from the AMS sampling site.