Aerosol properties and composition before and after the Manaus plume measured at the ground sites of the GoAmazon 2014/15 experiment

 

Authors

Paulo Artaxo — University of Sao Paulo
Henrique de Melo Jorge Barbosa — University of Maryland, Baltimore County
Joel Brito —
Samara Carbone — University of Sao Paulo
Clarice Fiorese — University of Sao Paulo
Luciana Rizzo — Universidade Federal de Sao Paulo
Glauber Cirino — National Institute for Amazonian Research (INPA)
Luiz Augusto Toledo Machado — INPE-CPTEC
Scot T. Martin — Harvard University
Jian Wang — Washington University in St. Louis
Rodrigo Augusto Souza — Universidade do Estado do Amazonas

Category

GoAmazon – Clouds and aerosols in Amazonia

Description

As part of the GoAmazon2014/2015 experiment, several aerosol and trace gas monitoring stations are being operated for two years before and after the Manaus urban plume in Central Amazonia. Three sites are being operated in pristine conditions, with atmospheric properties under natural biogenic conditions. These three sites named T0 are ATTO (Amazon Tall Tower Observatory), ZF2 and EMBRAPA. After the air masses are exposed to the Manaus plume, one site (called T2) is being operated under the direct influence of the Manaus plume at 5 Km downwind. Finally, at about 150 Km downwind of Manaus is the T3 Manacapuru site. Aerosol chemical composition is being analyzed using filters for fine (PM2.5) and coarse mode aerosol as well as three real time Aerodyne ACSM (Aerosol Chemical Speciation Monitors) instruments. Optical properties were measured with several AE33 aethalometers and MAAP, and multi wavelengths nephelometers. Aerosol size distribution is determined using scanning mobility particle sizers in the range of 10 to 600 nm. The aerosol optical depth (AOD) was measured using AERONET sunphotometers before and after the Manaus plume, as well as several Lidar systems to determine the aerosol vertical profile. The three sites before the Manaus plume show remarkable similar variability in aerosol concentrations and optical properties. This pattern is very different at the T2 site, with large aerosol concentrations enhancing aerosol absorption and scattering significantly as a result of the Manaus pollution plume. The aerosol is very oxidized before being exposed to the Manaus plume, and this pattern changes significantly for T2 and T3 sites, with a much higher presence of less oxidized aerosol. Typical ozone concentrations at mid-day before Manaus plume is a low 10-12 ppb, value that changes to 50-70 ppb for air masses suffering the influence of Manaus plume. Aerosol size distribution also change significantly, with stronger presence of nucleation mode particles. Long term MODIS remote sensing images were analyzed and clearly shows differences in AOD and cloud properties before and after the Manaus plume. A detailed comparison of aerosol characteristics and composition for the several sites will be presented showing the evolution of aerosol and trace gases in GoAmazon2014/15.