Climate-observation on a high level - Amazon Tall Tower Observatory (ATTO)
The Amazon Tall Tower Observatory ATTO is 325 m high and the core component of a field observatory for atmospheric measurements in the Brazilian Amazon region.
In the middle of the isolated Brazilian Amazon rainforest, ATTO forms a unique scientific platform for observing the climatic, biogeochemical and atmospheric conditions in the central Amazon under the influence of climate change and extreme weather events. ATTO thus plays a decisive role in providing research data as a basis for political decisions in the areas of climate change, land use change and biodiversity.
This steel tower, equipped with numerous measuring instruments, was built between 2010 and 2017, funded by the German Federal Ministry of Education and Research (BMBF) together with the Brazilian Ministry of Research MCTIC. The BMBF funded this construction phase with over five million euros. The ATTO tower was officially inaugurated in 2015.
More than 200 scientists from all over the world are using the ATTO research infrastructure to investigate how intact Amazonian forests affect the regional and global climate, the greenhouse gas balance and air quality and how these will change in the course of global change. This will enable us to better understand the importance of the Amazon rainforest for the global climate and the impact of climate change on the forest. In particular, ATTO contributes to new insights for the improvement of global carbon cycle and climate models.
In the first research phase (2017-2021), which the BMBF has funded with additional four million euros, important results have already been achieved that contribute to filling a gap in the global observation networks with long-term climatic, biogeochemical and atmospheric measurements. For example, studies of the pristine atmosphere around ATTO in the rainy season have provided initial insights into how human influence has fundamentally changed the formation and composition of aerosols and thus possibly cloud characteristics and rainfall in Amazonia. This therefore has implications for the global climate.
As a result of this successful collaboration in the German-Brazilian ATTO project, the second research phase (ATTOplus) started in August 2021 and is being funded by the BMBF with five million euros for three more years. The aim of ATTOplus is to answer the question of how climate change and climate extremes influence the interactions between intact tropical forest in the central Amazon region and the atmosphere and what consequences this has for the region and worldwide.
In total, BMBF funding for ATTO atmospheric research will amount to about 15 million euros between 2009 and 2025.
A key strength of the ATTO research infrastructure is the combination of several disciplines in one place – these range from tropical forest ecology to cloud physics. This makes it possible to better understand the reactions in the atmosphere and improves the accuracy of predictions about how climatic and ecological processes react to the changing Earth system. ATTOplus thus makes an important contribution to the scientific foundation of climate policy decisions – both in Germany and worldwide.
In the first research phase (also known as the pilot phase) from 2017 to 2021, scientifically and socially relevant results were achieved and a total of 55 scientific publications were published in well-respected international scientific journals.
New findings from ATTO research include, for example:
- In the forests of the central Amazon region, 60 per cent of precipitation is returned to the atmosphere, with the majority being brought into the atmosphere by the transpiration of trees.
- A study analysing satellite data and ground-based methane measurements (including measurement data from ATTO) shows an increase in methane emissions from the Amazon since 2014, which most likely contributes to a global methane increase.
- The Amazon makes up only about four per cent of the land surface, but is responsible for about 25 to 40 per cent of global emissions of biogenic volatile organic compounds (BVOCs), such as those emitted by trees, into the atmosphere.
- The study of the pristine atmosphere around ATTO during the rainy season has provided the first insights into how human-induced climate change has fundamentally altered aerosols and possibly cloud properties and precipitation in the Amazon.
- ATTO researchers have found that long-range transport of Saharan dust and smoke from African savannah fires affect the nutrients and sunlight reaching the forest.
The second research phase of ATTO started in August 2021. The German project partners will receive around five million euros in funding from the BMBF over the next four years.
The participating institutions from Germany are the Max Planck Institute for Biogeochemistry in Jena (MPI-BGC, coordinator), the Max Planck Institute for Chemistry in Mainz (MPI-C), the Karlsruhe Institute of Technology (KIT) and the University of Mainz. On the Brazilian side, a large number of research institutions and universities are involved as cooperation partners, coordinated by the owner of the tower, the Amazon Research Institute INPA (Instituto Nacional de Pesquisas da Amazônia). These include the University of São Paulo and the National Institute for Space Research in Brazil (INPE).
The ATTO tower was already equipped with additional instruments during the pilot phase. First series of measurements were initiated and new findings analysed. On this groundwork, the following key areas of work will now be deepened and expanded with longer-term series of measurements in the ATTOplus funding phase:
- the processes of greenhouse gas sources and sinks in the Amazon rainforest are to be investigated and understood in more detail. This will minimise existing uncertainties, particularly in determining the global carbon budget.
- chemical and physical processes in the atmosphere above the Amazon region and their feedback mechanisms on the climate will be intensively analysed.
- biogenic volatile organic compounds (BVOC) as well as aerosols and clouds above the tropical forest are measured and analysed. This will further clarify the important role of the forest area in regulating cloud cover, precipitation and water balance.
- to expand the understanding of the role of extreme weather events (including droughts, floods and storms) on the interactions between forests and the atmosphere.
- to set up a database structure that can be connected, in which measurement data from ATTO and other projects can be made available and utilised. This should make the results of ATTO available to the global scientific community.
The ATTOplus funding phase is intended to help intensify German-Brazilian research and cooperation in order to prepare the ATTO research infrastructure for broader scientific utilisation. This will also facilitate networking and synergies with other internationally established research infrastructures such as ACTRIS and ICOS.
With the help of the measurements on the tower, the carbon dioxide released and stored by the forest can be quantified. This allows reliable conclusions to be drawn about the rainforest as a carbon source or sink. This measurement data is of enormous importance in order to be able to make more precise statements on climate development.
Furthermore, measurements of aerosols on the tower provide insights into the processes that lead to cloud formation and therefore play a major role in the water cycle. For example, the scientific understanding of the significance of the "flying rivers" in the Amazon can be deepened. These are large masses of water that evaporate from the humid forest and can thus transport the water further afield in the form of clouds.
Overall, however, the Amazon rainforest is already severely affected by climate change and ongoing deforestation. The investigations at ATTO therefore also serve to develop an understanding of the "tipping points" – the tipping points of the global climate system - and to make predictions about how resilient the Amazon forest is and what impact human activities and climate change have on this important ecosystem.
The Amazon region is one of the most important regions for the global climate system, as it is the largest water and CO2 reservoir on earth. It therefore influences the overall stability of the Earth system and its global carbon cycles. Due to its chemical and physical processes in the atmosphere, the Amazon makes an important contribution as a regulator of the global climate. The gigantic evaporation from its forests creates clouds and currents that cool and influence the entire climate. Changes to this system therefore have a global impact.
A location was deliberately chosen for the ATTO research infrastructure where the influence of humans would hardly be felt. Located far from the nearest major city, Manaus, ATTO's central location in the Amazon region offers unique opportunities for climate, atmospheric and ecosystem research. The air over the central Amazon basin is the cleanest in the world during the rainy season. Here, the interaction between forest and atmosphere can be studied under conditions close to those of pre-industrial times. Due to its altitude, the ATTO measurements can record processes within a radius of several hundred square kilometres and thus cover a large part of the Amazon basin. This means that the effects of climate change and the influence of humans on one of the most unspoilt areas of the world can be researched particularly well.
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