Early-Warning Signals for a Critical Transition in the Coupled Amazon Rainforest-South American Monsoon System

2021 ◽  
Author(s):  
Nils Bochow
Keyword(s):  
Early Warning ◽  
Amazon Rainforest ◽  
South American ◽  
Critical Transition ◽  
The South ◽  
Warning Signals ◽  
Early Warning Signals ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System

<p>The Amazon rainforest is widely recognised as a potential tipping element in the Earth's climate system. While several studies suggest a sudden dieback of the rainforest ecosystem after partial deforestation [e.g., 1, 2], there is still a lack of understanding where to search for early-warning signals that might precede such a dieback. In this work we employ a non-linear model of the moisture transport across the Amazon Basin to propose several statistical and physical early warning signals for a critical transition in the coupled dynamics of the Amazon rainforest and the atmospheric circulation of the South American monsoon. </p><p>Widespread deforestation and its effects on evapotranspiration and radiation have been shown to potentially trigger a collapse of the positive feedback related to latent heat release over the rainforest [3], resulting in substantially reduced rainfall amounts. The model includes a nonlinear contribution representing the acceleration of low-level moisture flow caused by condensational latent heating.  </p><p>Guided by our modelling results, we associate characteristic changes in the hydrological cycle as well as statistical indicators in observed data with deforestation-induced circulation changes that are consistent with the identified early-warning signals. Our findings indicate that in response to deforestation, the coupled atmosphere-vegetation system is destabilising and that further deforestation could trigger a transition of the Amazon rainforest to a savanna state. </p><p>[1] Nobre, C. A., & Borma, L. D. S. (2009). “Tipping points” for the Amazon forest. Current Opinion in Environmental Sustainability. https://doi.org/10.1016/j.cosust.2009.07.003</p><p>[2] Hirota, M., Holmgren, M., Van Nes, E. H., & Scheffer, M. (2011). Global resilience of tropical forest and savanna to critical transitions. Science, 334(6053), 232–235. https://doi.org/10.1126/science.1210657</p><p>[3] Boers, N., Marwan, N., Barbosa, H. M. J., & Kurths, J. (2017). A deforestation-induced tipping point for the South American monsoon system. Scientific Reports, 7. https://doi.org/10.1038/srep41489</p>

scholarly journals Insolation and Greenhouse Gas Forcing of the South American Monsoon System Across Three Glacial‐Interglacial Cycles

2020 ◽  
Vol 47 (14) ◽  
Author(s):  
Alicia Hou ◽  
André Bahr ◽  
Jacek Raddatz ◽  
Silke Voigt ◽  
Markus Greule ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
South American ◽  
The South ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System

scholarly journals Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems—New Perspectives using the SISAL Database

Quaternary ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 6 ◽  
Author(s):  
Michael Deininger ◽  
Brittany Marie Ward ◽  
Valdir F. Novello ◽  
Francisco W. Cruz
Keyword(s):  
South America ◽  
Late Quaternary ◽  
Precipitation Amount ◽  
Ice Age ◽  
Convergence Zone ◽  
South American ◽  
The South ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System

Here we present an overview of speleothem δ18O records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical speleothem δ18O time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millennia. Precession driven summertime insolation is the main driver of convective variability over the continent during the last 120 kyrs (from present day to 120 kyrs BP), including the Holocene. However, there is a dipole between speleothem δ18O records from western and eastern South America. Records located in the central region of Brazil are weakly affected by insolation-driven variability, and instead are more susceptible to the variability associated with the South Atlantic Convergence Zone (SACZ). Cold episodic events in the Northern Hemisphere, such as Heinrich and Bond Events, and the Little Ice Age, increase the convective activity of the SAMS, resulting in increased precipitation amount in South America.

Moisture and heat budgets of the south American monsoon system: climatological aspects

2016 ◽  
Vol 130 (1-2) ◽  
pp. 233-247
Author(s):  
Sâmia R. Garcia ◽  
Mary T. Kayano ◽  
Alan J. P. Calheiros ◽  
Rita Valéria Andreoli ◽  
Rodrigo Augusto Ferreira de Souza
Keyword(s):  
South American ◽  
The South ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System ◽  
Heat Budgets

scholarly journals Forecast Skill of the South American Monsoon System

2012 ◽  
Vol 25 (6) ◽  
pp. 1883-1889 ◽  
Author(s):  
Charles Jones ◽  
Leila M. V. Carvalho ◽  
Brant Liebmann
Keyword(s):  
South American ◽  
The South ◽  
South American Monsoon ◽  
Simple Index ◽  
Climatic Feature ◽  
Probabilistic Forecasts ◽  
Monsoon System ◽  
South American Monsoon System ◽  
Environmental Prediction ◽  
Mean Square Errors

Abstract The South American monsoon system (SAMS) is the most important climatic feature in South America and is characterized by pronounced seasonality in precipitation. This study uses the National Centers for Environmental Prediction Climate Forecast System, reforecasts version 2 (CFSRv2), to investigate the skill of probabilistic forecasts of onset and demise dates, duration, and amplitude of SAMS during 1982–2009. A simple index based on the empirical orthogonal function of precipitation anomalies is employed to characterize onsets, demises, durations, and amplitudes of SAMS. The CFSv2 model has useful skill to forecast seasonal changes in SAMS. Probabilistic forecasts of onset and demise dates have 16.5% and 43.3% improvements, respectively, over climatological forecasts. Verification of hindcasts of durations and amplitudes of SAMS shows relatively small biases and root-mean-square errors.

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