scholarly journals Land cover and its transformation in the backward trajectory footprint region of the Amazon Tall Tower Observatory

2019 ◽  
Vol 19 (13) ◽  
pp. 8425-8470 ◽  
Author(s):  
Christopher Pöhlker ◽  
David Walter ◽  
Hauke Paulsen ◽  
Tobias Könemann ◽  
Emilio Rodríguez-Caballero ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Rain Forest ◽  
Amazon Basin ◽  
Fire Regimes ◽  
Climatic Conditions ◽  
Eastern Basin ◽  
Amazon Rain Forest ◽  
Tall Tower ◽  
Critical Aspects

Abstract. The Amazon rain forest experiences the combined pressures from human-made deforestation and progressing climate change, causing severe and potentially disruptive perturbations of the ecosystem's integrity and stability. To intensify research on critical aspects of Amazonian biosphere–atmosphere exchange, the Amazon Tall Tower Observatory (ATTO) has been established in the central Amazon Basin. Here we present a multi-year analysis of backward trajectories to derive an effective footprint region of the observatory, which spans large parts of the particularly vulnerable eastern basin. Further, we characterize geospatial properties of the footprint regions, such as climatic conditions, distribution of ecoregions, land cover categories, deforestation dynamics, agricultural expansion, fire regimes, infrastructural development, protected areas, and future deforestation scenarios. This study is meant to be a resource and reference work, helping to embed the ATTO observations into the larger context of human-caused transformations of Amazonia. We conclude that the chances to observe an unperturbed rain forest–atmosphere exchange at the ATTO site will likely decrease in the future, whereas the atmospheric signals from human-made and climate-change-related forest perturbations will increase in frequency and intensity.

scholarly journals Land cover and its transformation in the backward trajectory footprint region of the Amazon Tall Tower Observatory

2018 ◽  
Author(s):  
Christopher Pöhlker ◽  
David Walter ◽  
Hauke Paulsen ◽  
Tobias Könemann ◽  
Emilio Rodríguez-Caballero ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Rain Forest ◽  
Amazon Basin ◽  
Fire Regimes ◽  
Climatic Conditions ◽  
Eastern Basin ◽  
Amazon Rain Forest ◽  
Tall Tower ◽  
Critical Aspects

Abstract. The Amazon rain forest experiences the combined pressures from man-made deforestation and progressing climate change, causing severe and potentially disruptive perturbations of the ecosystem's integrity and stability. To intensify research on critical aspects of Amazonian biosphere-atmosphere exchange, the Amazon Tall Tower Observatory (ATTO) has been established in the central Amazon Basin. Here we present a multi-year analysis of backward trajectories to derive an effective footprint region of the observatory, which spans large parts of the particularly vulnerable eastern basin. Further, we characterize geospatial properties of the footprint regions, such as climatic conditions, distribution of ecoregions, land cover categories, deforestation dynamics, agricultural expansion, fire regimes, infrastructural development, protected areas, as well as future deforestation scenarios. This study is meant to be a resource and reference work, helping to embed the ATTO observations into the larger context of man-made transformations of Amazonia. We conclude that the chances to observe an unperturbed rain forest-atmosphere exchange will likely decrease in the future, whereas the atmospheric signals from man-made and climate change-related forest perturbations will likewise increase in frequency and intensity.

scholarly journals African volcanic emissions influencing atmospheric aerosol particles over the Amazon rain forest

2017 ◽  
Author(s):  
Jorge Saturno ◽  
Florian Ditas ◽  
Marloes Penning de Vries ◽  
Bruna A. Holanda ◽  
Mira L. Pöhlker ◽  
...  
Keyword(s):  
Rain Forest ◽  
Amazon Basin ◽  
Dimethyl Sulfide ◽  
Aerosol Particles ◽  
Amazon Region ◽  
Volcanic Emissions ◽  
Airborne Measurements ◽  
Amazon Rain Forest ◽  
Sulfur Emissions

Abstract. Long-range transport (LRT) plays an important role in the Amazon rain forest by bringing in different primary and secondary aerosol particles from distant sources. The atmospheric oxidation of dimethyl sulfide (DMS), emitted from marine plankton, is considered an important sulfate source over the Amazon rain forest, with a lesser contribution from terrestrial soil and vegetation sulfur emissions. Volcanic sulfur emissions from Africa could be a source of particulate sulfate to the Amazonian atmosphere upon transatlantic transport but no observations have been published. By using satellite observations, together with ground‑based and airborne aerosol particle observations, this paper provides evidence of the influence that volcanic emissions have on the aerosol properties that have been observed in central Amazonia. Under the volcanic influence, sulfate mass concentrations reached up to 3.6 µg m−3 (hourly mean) at ground level, the highest value ever reported in the Amazon region. The hygroscopicity parameter was higher than the characteristic dry-season average, reaching a maximum of 0.36 for accumulation mode aerosol particles. Airborne measurements and satellite data indicated the transport of two different volcanic plumes reaching the Amazon Basin in September 2014 with a sulfate-enhanced layer at an altitude between 4 and 5 km. These observations show that remote volcanic sources can episodically affect the aerosol cycling over the Amazon rain forest and perturb the background conditions. Further studies should address the long-term effect of volcanogenic aerosol particles over the Amazon Basin by running long-term and intensive field measurements in the Amazon region and by monitoring African emissions and their transatlantic transport.

scholarly journals Effects of Twenty-First-Century Climate Change on the Amazon Rain Forest

2008 ◽  
Vol 21 (3) ◽  
pp. 542-560 ◽  
Author(s):  
Kerry H. Cook ◽  
Edward K. Vizy
Keyword(s):  
Climate Change ◽  
Rain Forest ◽  
Model Simulation ◽  
Coupled Model ◽  
Atmospheric Model ◽  
First Century ◽  
Surface Boundary ◽  
Subtropical Climate ◽  
Amazon Rain Forest ◽  
Twenty First Century

Abstract A regional atmospheric model with 60-km resolution is asynchronously coupled with a potential vegetation model to study the implications of twenty-first-century climate change for the tropical and subtropical climate and vegetation of South America. The coupled model produces an accurate simulation of the present day climate and vegetation. Future climate is simulated by increasing atmospheric CO2 levels to 757 ppmv and imposing lateral and surface boundary conditions derived from a GCM simulation for 2081–2100 from the Canadian Climate Center GCM. The coupled regional model simulation projects a 70% reduction in the extent of the Amazon rain forest by the end of the twenty-first century and a large eastward expansion of the caatinga vegetation that is prominent in the Nordeste region of Brazil today. These changes in vegetation are related to reductions in annual mean rainfall and a modification of the seasonal cycle that are associated with a weakening of tropical circulation systems.

scholarly journals Could Protected Areas in Brazil’s Semi-Arid Conserve Endangered Birds Facing Climatic and Land Cover Changes?

2020 ◽  
pp. 50-70
Author(s):  
Tiago Castro Silva ◽  
Lara Gomes Côrtes ◽  
Marinez Ferreira de Siqueira
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Protected Areas ◽  
Land Cover Change ◽  
Ecological Niche ◽  
Climate Changes ◽  
Global Climate ◽  
Climatic Conditions ◽  
Global Climate Changes ◽  
The Face

Protected areas act as pillars on which conservation strategies are built. Besides human activities, global climate changes are an additional concern to species’ conservation. In northeastern Brazil, climate change should lead to a replacement of the current native vegetation by semi-desert vegetation. This study evaluates whether the protected areas of the Caatinga can contribute to the maintenance of suitable climatic conditions for endangered birds over time in the face of global climate changes and land cover change. We used ecological niche models as input layers in a spatial prioritization program, in which stability indices were used to weight the targets. Results predicted that most taxa (18) will have their suitability lowered in the future, and all taxa (23) will have their ecological niche geographically displaced. However, our results showed that the Caatinga’s protected areas system integrated with a set of priority areas can maintain suitable climatic conditions for endangered birds in the face of climate change and land cover change. On average, Caatinga’s protected areas system could protect climatic stability areas at least 1.7 times greater than the scenarios without it. This reinforces the importance of protected areas as a biodiversity conservation strategy. 
  

scholarly journals Impact of a drier Early–Mid-Holocene climate upon Amazonian forests

2008 ◽  
Vol 363 (1498) ◽  
pp. 1829-1838 ◽  
Author(s):  
Francis E Mayle ◽  
Mitchell J Power
Keyword(s):  
Amazon Basin ◽  
Forest Cover ◽  
Cloud Forest ◽  
Fire Regimes ◽  
Climatic Conditions ◽  
Spatial And Temporal Variation ◽  
Cloud Base ◽  
Amazon Forest ◽  
The Impact ◽  
Forest Biome

This paper uses a palaeoecological approach to examine the impact of drier climatic conditions of the Early–Mid-Holocene ( ca 8000–4000 years ago) upon Amazonia's forests and their fire regimes. Palaeovegetation (pollen data) and palaeofire (charcoal) records are synthesized from 20 sites within the present tropical forest biome, and the underlying causes of any emergent patterns or changes are explored by reference to independent palaeoclimate data and present-day patterns of precipitation, forest cover and fire activity across Amazonia. During the Early–Mid-Holocene, Andean cloud forest taxa were replaced by lowland tree taxa as the cloud base rose while lowland ecotonal areas, which are presently covered by evergreen rainforest, were instead dominated by savannahs and/or semi-deciduous dry forests. Elsewhere in the Amazon Basin there is considerable spatial and temporal variation in patterns of vegetation disturbance and fire, which probably reflects the complex heterogeneous patterns in precipitation and seasonality across the basin, and the interactions between climate change, drought- and fire susceptibility of the forests, and Palaeo-Indian land use. Our analysis shows that the forest biome in most parts of Amazonia appears to have been remarkably resilient to climatic conditions significantly drier than those of today, despite widespread evidence of forest burning. Only in ecotonal areas is there evidence of biome replacement in the Holocene. From this palaeoecological perspective, we argue against the Amazon forest ‘dieback’ scenario simulated for the future.

The Relevance of Biogeochemistry to Amazon Development and Conservation

2001 ◽  
Author(s):  
Michael McClain
Keyword(s):  
Rain Forest ◽  
Amazon Basin ◽  
Biological Diversity ◽  
Regional Climate ◽  
Ecological Integrity ◽  
The Public ◽  
Amazon Rain Forest ◽  
News Service ◽  
Gold Miners ◽  
Earth’S Climate

To read the press of recent years, one might imagine that the fate of the world rests in the hands of those who would develop the Amazon basin. Waves of incoming colonists are blamed for the bulk of the deforestation and development (Schomberg 1998), but Asian logging firms, multinational oil companies, and gold miners are also portrayed as destructive agents hacking down the forest, systematically undermining its biodiversity, and severely contaminating its myriad ecosystems (Althaus 1996, Ferreira 1996, James 1998). The effects of these varied threats are regularly broadcast in alarming tones. Rueters News Service warned in January 1998 that “Brazil’s Amazon rain forest, the world’s richest trove of biological diversity and source of much of the Earth’s oxygen, continues to be ravaged” (Craig 1998). And, in April 1999, a writer for the Associated Press communicated the “fear” of unspecified scientists that “damage to the rain forest... could throw the Earth’s climate out of balance” (Donn 1999). Clearly, the fate of the Amazon and the implications of its fate to the overall Earth system are topics of enormous scientific and popular interest. While there is little disagreement that the complete destruction of Amazon forests would be catastrophic, what about partial deforestation of the region? How much, and which parts, of the Amazon can be converted to sustainable human land uses without compromising the ecological integrity of the conserved areas? How might this development impact regional climate, adjoining coastal systems, and overall global processes? Answers to these volatile questions remain elusive and seemingly endless strands of controversy swirl about them. At the heart of the matter, yet largely beyond the public discussion, are biogeochemical cycles that support and regulate the functioning of the Amazonia’s biological systems. Moreover, it is the incomplete understanding of these cycles that promotes uncertainty and feeds the controversy. The purpose of this book is to present a coherent assessment of our current understanding of the biogeochemical functioning of the Amazon basin. Although it is surely presumptuous to assume that this presentation will shed sufficient light on the uncertainties to eliminate the current controversies, we hope that it will provide a basis for lifting the discussion to a higher level.

Will Amazonia Dry Out? Magnitude and Causes of Change from IPCC Climate Model Projections

2012 ◽  
Vol 16 (3) ◽  
pp. 1-27 ◽  
Author(s):  
Brian Cook ◽  
Ning Zeng ◽  
Jin-Ho Yoon
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Rain Forest ◽  
Dry Season ◽  
Future Climate Change ◽  
Vegetation Model ◽  
Co2 Fertilization ◽  
Dynamic Vegetation Model ◽  
The Core ◽  
Amazon Rain Forest

Abstract The Amazon rain forest may undergo significant change in response to future climate change. To determine the likelihood and causes of such changes, the authors analyzed the output of 24 models from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) and a dynamic vegetation model, Vegetation–Global–Atmosphere–Soil (VEGAS), driven by these climate output. Their results suggest that the core of the Amazon rain forest should remain largely stable because rainfall in the core of the basin is projected to increase in nearly all models. However, the periphery, notably the southern edge of Amazonia and farther south into central Brazil (SAB), is in danger of drying out, driven by two main processes. First, a decline in precipitation of 11% during the southern Amazonia’s dry season (May–September) reduces soil moisture. Two dynamical mechanisms may explain the forecast reduction in dry season rainfall: 1) a general subtropical drying under global warming when the dry season southern Amazon basin is under the control of subtropical high pressure and 2) a stronger north–south tropical Atlantic sea surface temperature gradient and, to a lesser degree, a warmer eastern equatorial Pacific. The drying corresponds to a lengthening of the dry season by approximately 10 days. The decline in soil moisture occurs despite an increase in precipitation during the wet season, because of nonlinear responses in hydrology associated with the decline in dry season precipitation, ecosystem dynamics, and an increase in evaporative demand due to the general warming. In terms of ecosystem response, higher maintenance cost and reduced productivity under warming may also have additional adverse impact. Although the IPCC models have substantial intermodel variation in precipitation change, these latter two hydroecological effects are highly robust because of the general warming simulated by all models. As a result, when forced by these climate projections, a dynamic vegetation model VEGAS projects an enhancement of fire risk by 20%–30% in the SAB region. Fire danger reaches its peak in Amazonia during the dry season, and this danger is expected to increase primarily because of the reduction in soil moisture and the decrease in dry season rainfall. VEGAS also projects a reduction of about 0.77 in leaf area index (LAI) over the SAB region. The vegetation response may be partially mediated by the CO2 fertilization effect, because a sensitivity experiment without CO2 fertilization shows a higher 0.89 decrease in LAI. Southern Amazonia is currently under intense human influence as a result of deforestation and land-use change. Should this direct human impact continue at present rates, added pressure to the region’s ecosystems from climate change may subject the region to profound changes in the twenty-first century.

scholarly journals A New Background Method for Greenhouse Gases Flux Calculation Based in Back-Trajectories Over the Amazon

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 734
Author(s):  
Lucas Gatti Domingues ◽  
Luciana Vanni Gatti ◽  
Afonso Aquino ◽  
Alber Sánchez ◽  
Caio Correia ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Rain Forest ◽  
Vertical Profile ◽  
Amazon Basin ◽  
Spatial Scales ◽  
Co2 Flux ◽  
Back Trajectory ◽  
Amazon Forest ◽  
Back Trajectories ◽  
Amazon Rain Forest

The large amount of carbon stored in trees and soils of the Amazon rain forest is under pressure from land use as well as climate change. Therefore, various efforts to monitor greenhouse gas exchange between the Amazon forest and the atmosphere are now ongoing, including regular vertical profile (surface to 4.5 km) greenhouse gas measurements across the Amazon. These profile measurements can be used to calculate fluxes to and from the rain forest to the atmosphere at large spatial scales by considering the enhancement or depletion relative to the mole fraction of air entering the Amazon basin from the Atlantic, providing an important diagnostic of the state, changes and sensitivities of the forests. Previous studies have estimated greenhouse gas mole fractions of incoming air (‘background’) as a weighted mean of mole fractions measured at two background sites, Barbados (Northern Hemisphere) and Ascension (Southern hemisphere) in the Tropical Atlantic, where the weights were based on sulphur hexafluoride (SF6) measured locally (in the Amazon vertical profiles) and at the two background sites. However, this method requires the accuracy and precision of SF6 measurements to be significantly better than 0.1 parts per trillion (picomole mole−1), which is near the limit for the best SF6 measurements and assumes that there are no SF6 sources in the Amazon basin. We therefore present here an alternative method. Instead of using SF6, we use the geographical position of each air-mass back-trajectory when it intersects the limit connecting these two sites to estimate contributions from Barbados versus Ascension. We furthermore extend the approach to include an observation site further south, Cape Point, South Africa. We evaluate our method using CO2 vertical profile measurements at a coastal site in Brazil comparing with values obtained using this method where we find a high correlation (r2 = 0.77). Similarly, we obtain good agreement for CO2 background when comparing our results with those based on SF6, for the period 2010–2011 when the SF6 measurements had excellent precision and accuracy. We also found high correspondence between the methods for background values of CO, N2O and CH4. Finally, flux estimates based on our new method agree well with the CO2 flux estimates for 2010 and 2011 estimated using the SF6-based method. Together, our findings suggest that our trajectory-based method is a robust new way to derive background air concentrations for the purpose of greenhouse gas flux estimation using vertical profile data.

scholarly journals Impacts of future deforestation and climate change on the hydrology of the Amazon basin: a multi-model analysis with a new set of land-cover change scenarios

2016 ◽  
Author(s):  
Matthieu Guimberteau ◽  
Philippe Ciais ◽  
Agnès Ducharne ◽  
Juan Pablo Boisier ◽  
Ana Paula Dutra Aguiar ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Land Cover Change ◽  
River Discharge ◽  
General Circulation ◽  
Amazon Basin ◽  
Dry Season ◽  
Forest Area ◽  
Basin Scale ◽  
Concentration Changes

Abstract. Neglecting any atmospheric feedback to precipitation, deforestation in Amazon, i.e., replacement of trees by shallow rooted short vegetation, is expected to decrease evapotranspiration (ET). Under energy-limited conditions, this process should lead to higher soil moisture and a consequent increase in river discharge. The magnitude and sign of the response of ET to deforestation depends both on land-cover change (LCC), and on climate and CO2 concentration changes in the future. Using three regional LCC scenarios recently established for the Brazilian and Bolivian Amazon, we investigate the combined impacts of deforestation and climate change on the surface hydrology of the Amazon basin for this century at sub-basin scale. For each LCC scenario, three land surface models (LSMs), LPJmL-DGVM, INLAND-DGVM and ORCHIDEE, are forced by bias-corrected climate simulated by three General Circulation Models (GCMs) for different scenarios of the IPCC 4th Assessment Report (AR4). The GCM results indicate that by 2100, without deforestation, the temperature will have increased by a mean of 3.3 °C (a range of 1.7 to 4.5 °C) over the Amazon basin, intensifing the regional water cycle, whereby precipitation, ET and runoff increase by 8.5, 5.0 and 14 %, respectively. However, under this same scenario in south-east Amazonia, precipitation decreases by 10 % at the end of the dry season and the three LSMs estimate a 6 % decrease of ET, which does not compensate for lower precipitation. Runoff in southeastern Amazonia decreases by 22 %, reducing minimum river discharge from the Rio Tapajós catchment by 31 % in 2100. The low LCC scenario projects a 7 % decline in the area of Amazonian forest by 2100, as compared to 2009; for the high LCC scenario the projection is a 34 % decline. In the extreme deforestation scenario, forest loss partly offsets (−2.5 %) the positive effect of climate change on increasing ET and slightly amplifies (+3.0 %) the increase of runoff. Effects of deforestation are more pronounced in the southern part of the Amazon basin, in particular in the Rio Madeira catchment where up to 56 % of the 2009 forest area is lost. The effect of deforestation on water budgets is more severe at the end of the dry season in the Tapajós and the Xingu catchments where the decrease of ET due to climate change is amplified by forest area loss. Deforestation enhances runoff during this period (+35 %) offsetting the negative effect of climate change (−22 %), and balances the decrease of low flows in the Rio Tapajós.

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