This forest site is located 60 km northwest to Manaus urban area, at the ZF2 Ecological Station (2.59S, 60.21W, 110 m asl), within the INPA (Brazilian National Institute for Amazonian Research) Cuieiras forest reserve. There, from the point of view of aerosol properties, the wet season corresponds to the period Jan–Jun, whereas the dry season corresponds to Jul– Dec [Rizzo et al., 2013].
No biomass burning occurs in the reservation or close to the site. During the wet season, the prevailing trade winds blow over vast expanses of intact tropical forest before reaching the measurement tower, thus representative of near-pristine conditions. However, during part of the year, the site is affected by regional transport of pollutants, most of it from long-range transported biomass burning emissions [Artaxo et al., 2013].
All measurements are taken under dry conditions (RH 30–40%) by use of an automatic diffusion dryer in the sampling line[]. An inlet with 50% aerodynamic cut-off of 7 um is used for sampling. Inlet lines run from the measurement level (39 m agl, about 10 m above the canopy height) to an air-conditioned container at ground level. These observations are taken at the TT34 tower. Housing for the researchers and a diesel generator that provide the power supply were located respectively 0.33 km and 0.72 km to the west of the sampling site (downwind). A detailed description of the ZF2 TT34 tower measurement site and surrounding area can be found in Martin et al [2010].
Detail of the TT34 tower at ZF2 (left) and measurement station (right) are shown.
Instruments
Measurements at this site varied from time to time. It generally includes:
- Aerosol particle absorption are measured using a MAAP photometer (MultiAngle Absorption Photometry – Thermo Inc., Model 5012) (Petzold et al., 2005).
- Aerosol particle scattering coefficients are measured using a three wavelength integrating nephelometer (TSI Model 3563) operating at 450, 550 and 700 nm (Anderson et al., 1996).
- Aerosol particle number size distribution in fine mode are measured using a mobility particle size spectrometers (10–500 nm) a TSI 3936 SMPS (Scanning Mobility Particle Sizer).
- Coarse mode particle number size distributions are measured using an OPC-Grimm Model 1.109 (300 nm–20 μm) (Optical Particle Counter).
- Particle number concentrations are measured with condensation particle counters (TSI CPC models 3010, 3785 or 3772).
- Stacked Filter Units (SFU) are used to collect fine mode (Dp <2.0 μm) and coarse mode (Dp >2.0 μm) aerosols, with integrating periods ranging from 2 to 5 days.
Instrumentation running at ZF2 is shown shown.