Duque Gardeazábal (2025) Some sources of hydroclimate and renewable energy variability in tropical South America

Identification

• Journal: BORIS Theses (Bern Open Research Information System) (Bern University Library, Hochschulstrasse 6, 3012 Bern, Switzerland)
• Year: 2025
• Date: 2025-12-03
• Authors: Duque Gardeazábal, Nicolás
• DOI: 10.48549/6949

Research Groups

• Universität Bern, Bern
• Oeschger Centre for Climate Change Research (OCCR)
• Institute of Geography

Short Summary

This thesis investigates how ocean-atmospheric modes and external aerosol forcing modulate hydroclimatic variability and potential solar and wind energy in tropical South America. It reveals distinct regional and seasonal impacts of Atlantic modes, the influence of these modes and ENSO on renewable energy capacity factors, and the differing effects of anthropogenic and volcanic aerosols on rainfall.

Objective

• To investigate how a chain of physical processes, induced by ocean–atmospheric modes (ENSO, AMM, Atl3), modulate hydroclimatic variability and the potential solar and wind energy in tropical South America.
• To explore how external aerosol forcing (anthropogenic and volcanic) influences these mechanisms and subsequently rainfall in tropical South America.

Study Configuration

• Spatial Scale: Tropical South America, including specific regions such as the North Caribbean, Eastern Brazil, the Andes (Peru/Bolivia), Guianas, and eastern Orinoco.
• Temporal Scale: Seasonal, interannual, and long-term hydroclimatic variability.

Methodology and Data

• Models used: Not explicitly stated as specific climate models. Analytical methods include composites and partial correlations.
• Data sources: Reanalysis data, satellite data, historical reanalyses, observations, and paleo-reanalysis.

Main Results

• Atlantic Meridional Mode (AMM) and Atlantic Niño (Atl3) influence South America's evapotranspiration, atmospheric circulation, and other variables, with seasonally and geographically distinct impacts. AMM-related anomalies migrate from eastern South America during austral autumn toward western Orinoco by austral spring, while Atl3 impacts are more localized in the Guianas and eastern Orinoco.
• Atlantic modes alter the water and energy cycles in different regions compared to El Niño–Southern Oscillation (ENSO).
• ENSO, AMM, and Atl3 influence wind and solar capacity factors in energy hubs (North Caribbean, Eastern Brazil, Andes) through modifications in sea level pressure, winds, moisture divergence, radiation, cross-equatorial winds, and clouds.
• Limited complementarity was found between wind and solar energy at interannual scales in the studied energy hubs.
• Anthropogenic aerosols progressively reduced the interhemispheric temperature gradient, displacing the Hadley circulation southward and subsequently rainfall.
• Volcanic aerosols are primarily associated with an overall reduction in rainfall, with some eruptions linked to meridional displacements of precipitation.

Contributions

• Provides a comprehensive understanding of the physical processes linking ocean-atmospheric modes (ENSO, AMM, Atl3) to hydroclimatic variability and renewable energy potential in tropical South America.
• Differentiates the regional and seasonal impacts of Atlantic modes from those of ENSO on water and energy cycles.
• Offers insights into the influence of anthropogenic and volcanic aerosols on long-term hydroclimatic variability and rainfall patterns in the region.
• The findings can lead to improved predictions of droughts, floods, and renewable energy variability, supporting early-warning systems and adaptation strategies in a vulnerable region.

Funding

• Not explicitly mentioned in the provided text.

Citation

@article{DuqueGardeazábal2025Some,
  author = {Duque Gardeazábal, Nicolás},
  title = {Some sources of hydroclimate and renewable energy variability in tropical South America},
  journal = {BORIS Theses (Bern Open Research Information System) (Bern University Library, Hochschulstrasse 6, 3012 Bern, Switzerland)},
  year = {2025},
  doi = {10.48549/6949},
  url = {https://doi.org/10.48549/6949}
}

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