The Amazon Tall Tower Observatory (ATTO) in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements

Abstract. The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next 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. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. 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 5 to 8 different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are made above the canopy as well as in the canopy space. They include light scattering and absorption, aerosol fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. Initial results from ecological, meteorological, and chemical studies at the ATTO site are presented in this paper.

Download Full-text

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-10723-2015 ◽

2015 ◽

Vol 15 (18) ◽

pp. 10723-10776 ◽

Cited By ~ 107

Author(s):

M. O. Andreae ◽

O. C. Acevedo ◽

A. Araùjo ◽

P. Artaxo ◽

C. G. G. Barbosa ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Amazon Basin ◽

Cloud Condensation Nuclei ◽

Heat Fluxes ◽

Atmospheric Conditions ◽

Additional Species ◽

Pilot Studies ◽

Forest Region ◽

Human Perturbations ◽

Tall Tower

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, NO2, 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.

Download Full-text

The challenge of simulating the sensitivity of the Amazonian cloud microstructure to cloud condensation nuclei number concentrations

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1591-2020 ◽

2020 ◽

Vol 20 (3) ◽

pp. 1591-1605 ◽

Cited By ~ 1

Author(s):

Pascal Polonik ◽

Christoph Knote ◽

Tobias Zinner ◽

Florian Ewald ◽

Tobias Kölling ◽

...

Keyword(s):

Amazon Basin ◽

Climate Model ◽

Cloud Condensation Nuclei ◽

Cloud Droplet ◽

Number Concentration ◽

Effective Radius ◽

Cloud Base ◽

Atmospheric Conditions ◽

Condensation Nuclei ◽

Aerosol Cloud

Abstract. The realistic representation of aerosol–cloud interactions is of primary importance for accurate climate model projections. The investigation of these interactions in strongly contrasting clean and polluted atmospheric conditions in the Amazon region has been one of the motivations for several field campaigns, including the airborne “Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems–Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (Global Precipitation Measurement) (ACRIDICON-CHUVA)” campaign based in Manaus, Brazil, in September 2014. In this work we combine in situ and remotely sensed aerosol, cloud, and atmospheric radiation data collected during ACRIDICON-CHUVA with regional, online-coupled chemistry-transport simulations to evaluate the model's ability to represent the indirect effects of biomass burning aerosol on cloud microphysical and optical properties (droplet number concentration and effective radius). We found agreement between the modeled and observed median cloud droplet number concentration (CDNC) for low values of CDNC, i.e., low levels of pollution. In general, a linear relationship between modeled and observed CDNC with a slope of 0.3 was found, which implies a systematic underestimation of modeled CDNC when compared to measurements. Variability in cloud condensation nuclei (CCN) number concentrations was also underestimated, and cloud droplet effective radii (reff) were overestimated by the model. Modeled effective radius profiles began to saturate around 500 CCN cm−3 at cloud base, indicating an upper limit for the model sensitivity well below CCN concentrations reached during the burning season in the Amazon Basin. Additional CCN emitted from local fires did not cause a notable change in modeled cloud droplet effective radii. Finally, we also evaluate a parameterization of CDNC at cloud base using more readily available cloud microphysical properties, showing that we are able to derive CDNC at cloud base from cloud-side remote-sensing observations.

Download Full-text

East Asian climate response to COVID-19 lockdown measures in China

Scientific Reports ◽

10.1038/s41598-021-96007-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sun-Seon Lee ◽

Jung-Eun Chu ◽

Axel Timmermann ◽

Eui-Seok Chung ◽

June-Yi Lee

Keyword(s):

Air Pollution ◽

Atmospheric Chemistry ◽

Cloud Condensation Nuclei ◽

Cloud Formation ◽

Atmospheric Conditions ◽

Anthropogenic Aerosol ◽

Surface Warming ◽

Anomalous Surface ◽

Additional Perturbation ◽

Aerosol Emissions

AbstractThe COVID-19 pandemic caused disruptions of public life and imposed lockdown measures in 2020 resulted in considerable reductions of anthropogenic aerosol emissions. It still remains unclear how the associated short-term changes in atmospheric chemistry influenced weather and climate on regional scales. To understand the underlying physical mechanisms, we conduct ensemble aerosol perturbation experiments with the Community Earth System Model, version 2. In the simulations reduced anthropogenic aerosol emissions in February generate anomalous surface warming and warm-moist air advection which promotes low-level cloud formation over China. Although the simulated response is weak, it is detectable in some areas, in qualitative agreement with the observations. The negative dynamical cloud feedback offsets the effect from reduced cloud condensation nuclei. Additional perturbation experiments with strongly amplified air pollution over China reveal a nonlinear sensitivity of regional atmospheric conditions to chemical/radiative perturbations. COVID-19-related changes in anthropogenic aerosol emissions provide an excellent testbed to elucidate the interaction between air pollution and climate.

Download Full-text

Aspectos micrometeorológicos da emissão de monoterpenos em uma floresta na Amazônia central

Ciência e Natura ◽

10.5902/2179460x30729 ◽

2018 ◽

Vol 40 ◽

pp. 150 ◽

Cited By ~ 1

Author(s):

Sarah Batalha ◽

Jeong-Hoo Park ◽

Eliane Alves ◽

Raoni Santana ◽

Roger Seco ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Amazon Basin ◽

Transfer Reaction ◽

Sonic Anemometer ◽

Brazilian Amazon ◽

Proton Transfer Reaction ◽

Mixing Ratio ◽

Forest Region ◽

Central Amazonia ◽

Volatile Organic

This research aimed to present results about the mixing ratio and flux of monoterpenes at a forest region of the Brazilian Amazon. It was used micrometeorology instrumentation (using a Sonic Anemometer) and analytical chemistry by a Proton Transfer Reaction - Time of Flight - Mass Spectrometer, PTR-ToF-MS. The calibration of the spectrometer was performed regularly using a gravimetric mix of standard gas containing different masses of volatile organic compounds. The results showed average mixing ration of monoterpenes of 0.185 ppbv and maximum emission flux of 1.495 mg m-2 h-1. It was concluded that this region presented a significant emission of monoterpenes in relation to another tropical forest in central Amazonia, evidencing the needing to improve studies about atmospheric chemistry in different forests of the Amazon Basin.

Download Full-text

Coupling between the JULES land-surface scheme and the CCATT-BRAMS atmospheric chemistry model (JULES-CCATT-BRAMS1.0): applications to numerical weather forecasting and the CO<sub>2</sub> budget in South America

Geoscientific Model Development Discussions ◽

10.5194/gmdd-6-453-2013 ◽

2013 ◽

Vol 6 (1) ◽

pp. 453-494 ◽

Cited By ~ 4

Author(s):

D. S. Moreira ◽

S. R. Freitas ◽

J. P. Bonatti ◽

L. M. Mercado ◽

N. M. É. Rosário ◽

...

Keyword(s):

South America ◽

Atmospheric Chemistry ◽

Land Surface ◽

Amazon Basin ◽

Mean Squared Error ◽

Weather Forecasting ◽

Dew Point ◽

Surface Model ◽

Co2 Concentrations ◽

Wide Range

Abstract. This article presents the development of a new numerical system denominated JULES-CCATT-BRAMS, which resulted from the coupling of the JULES surface model to the CCATT-BRAMS atmospheric chemistry model. The performance of this system in relation to several meteorological variables (wind speed at 10 m, air temperature at 2 m, dew point temperature at 2 m, pressure reduced to mean sea level and 6 h accumulated precipitation) and the CO2 concentration above an extensive area of South America is also presented, focusing on the Amazon basin. The evaluations were conducted for two periods, the wet (March) and dry (September) seasons of 2010. The statistics used to perform the evaluation included bias (BIAS) and root mean squared error (RMSE). The errors were calculated in relation to observations at conventional stations in airports and automatic stations. In addition, CO2 concentrations in the first model level were compared with meteorological tower measurements and vertical CO2 profiles were compared with aircraft data. The results of this study show that the JULES model coupled to CCATT-BRAMS provided a significant gain in performance in the evaluated atmospheric fields relative to those simulated by the LEAF (version 3) surface model originally utilized by CCATT-BRAMS. Simulations of CO2 concentrations in Amazonia and a comparison with observations are also discussed and show that the system presents a gain in performance relative to previous studies. Finally, we discuss a wide range of numerical studies integrating coupled atmospheric, land surface and chemistry processes that could be produced with the system described here. Therefore, this work presents to the scientific community a free tool, with good performance in relation to the observed data and re-analyses, able to produce atmospheric simulations/forecasts at different resolutions, for any period of time and in any region of the globe.

Download Full-text

Growth of nucleation mode particles in the summertime Arctic: a case study

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-7663-2016 ◽

2016 ◽

Vol 16 (12) ◽

pp. 7663-7679 ◽

Cited By ~ 61

Author(s):

Megan D. Willis ◽

Julia Burkart ◽

Jennie L. Thomas ◽

Franziska Köllner ◽

Johannes Schneider ◽

...

Keyword(s):

Cloud Condensation Nuclei ◽

Methanesulfonic Acid ◽

Lower Troposphere ◽

Atmospheric Conditions ◽

Aerosol Formation ◽

Radiative Balance ◽

Nucleation Mode ◽

Cloud Properties ◽

Marine Influence

Abstract. The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties and therefore radiative balance and climate. We present an analysis of an aerosol growth event observed in the Canadian Arctic Archipelago during summer as part of the NETCARE project. Under stable and clean atmospheric conditions, with low inversion heights, carbon monoxide less than 80 ppbv, and black carbon less than 5 ng m−3, we observe growth of small particles, <  20 nm in diameter, into sizes above 50 nm. Aerosol growth was correlated with the presence of organic species, trimethylamine, and methanesulfonic acid (MSA) in particles ∼ 80 nm and larger, where the organics are similar to those previously observed in marine settings. MSA-to-sulfate ratios as high as 0.15 were observed during aerosol growth, suggesting an important marine influence. The organic-rich aerosol contributes significantly to particles active as cloud condensation nuclei (CCN, supersaturation  =  0.6 %), which are elevated in concentration during aerosol growth above background levels of ∼ 100 to ∼ 220 cm−3. Results from this case study highlight the potential importance of secondary organic aerosol formation and its role in growing nucleation mode aerosol into CCN-active sizes in this remote marine environment.

Download Full-text

An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

Atmospheric Chemistry and Physics ◽

10.5194/acp-3-1609-2003 ◽

2003 ◽

Vol 3 (5) ◽

pp. 1609-1631 ◽

Cited By ~ 35

Author(s):

D. Brunner ◽

J. Staehelin ◽

H. L. Rogers ◽

M. O. Köhler ◽

J. A. Pyle ◽

...

Keyword(s):

Quantitative Methods ◽

Climate Models ◽

Model Performance ◽

Average Concentration ◽

Convective Transport ◽

Trace Gas ◽

Atmospheric Conditions ◽

Time Step ◽

Research Aircraft ◽

Gas Measurements

Abstract. A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observation points. This approach allows for a very close comparison with observations and fully accounts for the specific meteorological conditions during the measurement flights. This is important considering the often limited availability and representativity of such trace gas measurements. A new extensive database including all major research and commercial aircraft measurements between 1995 and 1998, as well as ozone soundings, was established specifically to support this type of direct comparison. Quantitative methods were applied to judge model performance including the calculation of average concentration biases and the visualization of correlations and RMS errors in the form of so-called Taylor diagrams. We present the general concepts applied, the structure and content of the database, and an overall analysis of model skills over four distinct regions. These regions were selected to represent various atmospheric conditions and to cover large geographical domains such that sufficient observations are available for comparison. The comparison of model results with the observations revealed specific problems for each individual model. This study suggests the further improvements needed and serves as a benchmark for re-evaluations of such improvements. In general all models show deficiencies with respect to both mean concentrations and vertical gradients of important trace gases. These include ozone, CO and NOx at the tropopause. Too strong two-way mixing across the tropopause is suggested to be the main reason for differences between simulated and observed CO and ozone values. The generally poor correlations between simulated and measured NOx values suggest that in particular the NOx input by lightning and the convective transport from the polluted boundary layer are still not well described by current parameterizations, which may lead to significant differences in the spatial and seasonal distribution of NOx in the models. Simulated OH concentrations, on the other hand, were found to be in surprisingly good agreement with measured values.

Download Full-text

Case studies of the impact of orbital sampling on stratospheric trend detection and derivation of tropical vertical velocities: solar occultation vs. limb emission sounding

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-11521-2016 ◽

2016 ◽

Vol 16 (18) ◽

pp. 11521-11534 ◽

Cited By ~ 9

Author(s):

Luis F. Millán ◽

Nathaniel J. Livesey ◽

Michelle L. Santee ◽

Jessica L. Neu ◽

Gloria L. Manney ◽

...

Keyword(s):

Case Studies ◽

Atmospheric Chemistry ◽

Stratospheric Ozone ◽

Sampling Bias ◽

Nonuniform Sampling ◽

Trend Detection ◽

Trace Gas ◽

Uniform Sampling ◽

Solar Occultation ◽

The Impact

Abstract. This study investigates the representativeness of two types of orbital sampling applied to stratospheric temperature and trace gas fields. Model fields are sampled using real sampling patterns from the Aura Microwave Limb Sounder (MLS), the HALogen Occultation Experiment (HALOE) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). The MLS sampling acts as a proxy for a dense uniform sampling pattern typical of limb emission sounders, while HALOE and ACE-FTS represent coarse nonuniform sampling patterns characteristic of solar occultation instruments. First, this study revisits the impact of sampling patterns in terms of the sampling bias, as previous studies have done. Then, it quantifies the impact of different sampling patterns on the estimation of trends and their associated detectability. In general, we find that coarse nonuniform sampling patterns may introduce non-negligible errors in the inferred magnitude of temperature and trace gas trends and necessitate considerably longer records for their definitive detection. Lastly, we explore the impact of these sampling patterns on tropical vertical velocities derived from stratospheric water vapor measurements. We find that coarse nonuniform sampling may lead to a biased depiction of the tropical vertical velocities and, hence, to a biased estimation of the impact of the mechanisms that modulate these velocities. These case studies suggest that dense uniform sampling such as that available from limb emission sounders provides much greater fidelity in detecting signals of stratospheric change (for example, fingerprints of greenhouse gas warming and stratospheric ozone recovery) than coarse nonuniform sampling such as that of solar occultation instruments.

Download Full-text

Dynamics and composition of the Asian summer monsoon anticyclone

10.5194/acp-2017-420 ◽

2017 ◽

Cited By ~ 1

Author(s):

Klaus-Dirk Gottschaldt ◽

Hans Schlager ◽

Robert Baumann ◽

Duy S. Cai ◽

Veronika Eyring ◽

...

Keyword(s):

Summer Monsoon ◽

Atmospheric Chemistry ◽

Asian Summer Monsoon ◽

Monsoon Season ◽

Lower Troposphere ◽

Equatorial Region ◽

Ozone Production ◽

Trace Gas ◽

Asian Summer ◽

Southern Fringe

Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) obtained during the Earth System Model Validation (ESMVal) campaign in September 2012 into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from the rest of the year. Air uplifted from the lower troposphere to the tropopause layer dominates the eastern part of the ASMA’s interior, while the western part is characterised by subsidence down to the mid-troposphere. Soluble compounds are being washed out when uplifted by convection in the eastern part, where lightning simultaneously replenishes reactive nitrogen in the upper troposphere. Net photochemical ozone production is significantly enhanced in the ASMA, contrasted by an ozone depleting regime in the mid-troposphere and more neutral conditions in autumn and winter. An analysis of multiple monsoon seasons in the simulation shows that stratospherically influenced tropopause layer air is regularly entrained at the eastern ASMA flank, and then transported in the southern fringe around the interior region. Observed and simulated tracer-tracer relations reflect photochemical O3 production, as well as in-mixing from the lower troposphere and the tropopause layer. The simulation additionally shows entrainment of clean air from the equatorial region by northerly winds at the western ASMA flank. Although the in situ measurements were performed towards the end of summer, the main ingredients needed for their interpretation are present throughout the monsoon season. A transition between two dynamical modes of the ASMA took place during the HALO ESMVal campaign. Transport barriers of the original anticyclone are overcome effectively when it splits up. Air from the fringe is stirred into the interiors of the new anticyclones and vice versa. Instabilities of this and other types occur quite frequently. Our study emphasises their paramountcy for the trace gas composition of the ASMA and its outflow into regions around the world.

Download Full-text

The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-505-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 505-522 ◽

Cited By ~ 62

Author(s):

G. L. Manney ◽

W. H. Daffer ◽

K. B. Strawbridge ◽

K. A. Walker ◽

C. D. Boone ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Lower Stratosphere ◽

High Arctic ◽

Trace Gas ◽

Satellite Measurements ◽

Broadband Emission ◽

Gas Measurements ◽

Chemistry Experiment ◽

Very High ◽

Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

Download Full-text