The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

Abstract

Abstract. The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future.The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO 2 , and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site.

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

“…3d. This is an indication of the dominance of fine mode aerosol (mostly BB related) during the dry season over the coarse mode aerosols that become more important in the wet season (i.e., PBAP, Saharan dust and sea salt), as previously observed at the ATTO site (Andreae et al, 2015; -Zuloaga et al, 2017). A similar seasonal trend has been observed at the ZF2 site, where å sca was 1.70 ± 1.41 and 1.48 ± 1.12 (30-min averages) for the dry and the wet season, respectively .…”

“…Initial results on non-refractory aerosol chemical composition at the ATTO site have already been reported by Andreae et al (2015) and a detailed paper on the long-term ACSM observations is being prepared by Carbone et al (2017). This online mass spectrometry technique detects organics, nitrate, sulfate, ammonium and chloride in the sub-micron (< 1 µm) aerosol size range (Ng et al, 2011).…”

“…Condensation nuclei (CN) number concentrations, N CN , and size distributions from 10 nm to 10 µm were continuously measured using several instruments including mobility and optical particle sizers (more details can be found in Andreae et al (2015)). In this study, we used coarse mode (> 1 µm) number and mass concentrations obtained by means of an optical particle sizer (OPS) model 3330 (TSI Inc., Shoreview, USA) to identify mineral dust transport events.…”

Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

“…The sampling period analyzed here comprises the wet-to-dry transition time (June-July 2014) and part of the dry season (August-September 2014). In the beginning of the measurement period (beginning of June), aerosol particle number concentrations were very low, in the order of 100-400 cm −3 , measured by a condensation particle counter (CPC) (Andreae et al, 2015). These typical wetseason conditions slightly changed during the transition season until the end of August, when particle number concentrations increased to around 500-2000 cm −3 (Andreae et al, 2015).…”

“…The results presented here are relevant for the study of valuable multi-wavelength data provided by the widely used Aethalometers. Andreae et al (2015).…”