GOAmazon

GOAmazon
Name	GOAmazon
Location	Amazon Rainforest, Brazil
Start	2014
Organiser	National Oceanic and Atmospheric Administration; U.S. Department of Energy
Partners	Brazilian National Institute for Space Research; Instituto Nacional de Pesquisas da Amazônia
Focus	atmospheric chemistry, cloud microphysics, aerosol–cloud–precipitation interactions

GOAmazon

GOAmazon is a multinational field campaign focused on aerosol, cloud, and atmospheric chemistry processes in the central Amazon Rainforest near Manaus. The program combines long-term observatories, intensive measurement periods, and modeling to investigate how urban emissions, biogenic sources, and regional meteorology influence cloud formation and precipitation. GOAmazon brought together institutions and investigators from the United States Department of Energy, National Aeronautics and Space Administration, Brazilian National Institute for Space Research, and multiple universities to study aerosol–cloud interactions under intact tropical forest conditions.

Overview

GOAmazon examined the atmospheric environment surrounding an isolated urban plume from Manaus as it interacts with background emissions from the Amazon Basin, including volatile organic compounds from forest canopies and biomass burning from regional sources such as the Xingu and Tapajós regions. The campaign used ground sites, aircraft platforms, and remote sensing towers to obtain measurements relevant to cloud microphysics, radiative transfer, and chemical transformation processes over the Tropical Atlantic-influenced continental interior. Investigators sought to constrain uncertainties in climate forcing identified by intercomparison studies such as those coordinated by the Intergovernmental Panel on Climate Change and to improve parameterizations used in models developed at centers including Los Alamos National Laboratory, Pacific Northwest National Laboratory, and National Center for Atmospheric Research.

Objectives and Scope

Primary objectives included quantifying aerosol sources and properties, assessing aerosol indirect effects on clouds and rainfall, and evaluating how anthropogenic perturbations alter natural biogenic emissions. GOAmazon aimed to test hypotheses relevant to cloud-resolving and Earth system models from institutions such as Lawrence Berkeley National Laboratory and Massachusetts Institute of Technology and to provide observational constraints for satellite retrievals from missions like Aqua (satellite), CloudSat, and CALIPSO. The scope encompassed seasonal variability, plume aging, and heterogeneous chemistry relevant to trace gases measured in networks such as Global Atmosphere Watch.

Experimental Design and Sites

The experimental design featured a suite of sites: an urban sampling location in Manaus, upwind and downwind forest sites on the Reserva Florestal Adolpho Ducke, and mobile platforms including instrumented towers and research aircraft such as DOE G-1, operated alongside flights by NASA DC-8 and other campaign aircraft. Sites were selected to capture gradient transects across the urban plume and background forest, leveraging existing infrastructure from long-term projects at INPA and tower networks co-located with flux stations used by programs coordinating with Large-Scale Biosphere–Atmosphere Experiment in Amazonia. Intensive operating periods were scheduled to coincide with seasonal transitions, including dry-season biomass burning episodes and wet-season convection associated with the South American Monsoon System.

Instrumentation and Methodology

GOAmazon employed advanced instrumentation for aerosol chemistry, size distribution, and cloud microphysics: high-resolution time-of-flight aerosol mass spectrometers from groups at Aerodyne Research, Inc., scanning mobility particle sizers developed in collaboration with TSI Incorporated, cloud condensation nuclei counters used by teams at University of Miami, and holographic cloud probes associated with University of Colorado Boulder. Trace gas analyzers measured ozone, nitrogen oxides, and volatile organic compounds using techniques from National Center for Atmospheric Research and academic partners including University of California, Berkeley and University of São Paulo. Remote sensing included ceilometers, Doppler cloud radars from Colorado State University, and lidar systems coordinated with NOAA Earth System Research Laboratories. Methodologies combined in situ sampling with aircraft transects, tethered balloon profiles, and inverse modeling approaches undertaken by groups at Imperial College London and University of Helsinki to attribute sources and process rates.

Key Findings and Publications

Results documented pronounced modulation of cloud droplet number concentrations and droplet effective radius by Manaus emissions, altering precipitation formation pathways and radiative forcing in ways summarized in publications in journals such as Science, Nature Geoscience, and Journal of Geophysical Research. Studies identified the chemical aging of organic aerosols and the role of secondary organic aerosol formation from isoprene oxidation pathways investigated in work linked to Max Planck Institute for Chemistry and Scripps Institution of Oceanography. Model–measurement comparisons revealed biases in convective parameterizations used by groups at European Centre for Medium-Range Weather Forecasts and U.S. National Weather Service parent institutions, prompting updates to aerosol–cloud modules and satellite retrieval algorithms referenced by NASA and NOAA science programs.

Collaborations and Funding

GOAmazon was a collaborative effort involving federal agencies such as the U.S. Department of Energy Office of Science and National Oceanic and Atmospheric Administration, Brazilian partners including Instituto Nacional de Pesquisas da Amazônia and Instituto Nacional de Pesquisas Espaciais, and international university consortia from United Kingdom, Germany, France, and Japan. Funding came from DOE atmospheric programs, NOAA research divisions, and national science agencies such as CNPq and FAPESP. Coordination involved data-sharing agreements and joint workshops hosted by institutions including University of Campinas and University of Arizona.

Impact and Legacy

GOAmazon provided long-term datasets that inform climate model development at centers like Lawrence Livermore National Laboratory and satellite validation efforts for European Space Agency missions. The campaign influenced policy-relevant assessments of land-use change impacts on regional climate and supported capacity building at Brazilian research institutions including INPA and USP. GOAmazon’s legacy includes improved process understanding of aerosol–cloud–precipitation interactions in tropical forests, enhanced observational networks, and a suite of open datasets and community model intercomparison exercises used by researchers at NOAA ESRL, NCAR, and academic partners worldwide.

Category:Field experiments