This study identifies 38 cases of windthrows in the Amazonia to explore the relationship between windthrows and the characteristics (storm passing time, cloud top temperature, and maximum precipitation) of mesoscale convective systems (MCSs) that produced them.
Fan-shaped dead forest patches were found over the entire Amazonia. These patches, over 37 hectares, affect the role the Amazon forests played in the world’s carbon cycle. Scientists found that frequent storms result in these dead forest patches, but how does the process happen? In this study, we explored the three characteristics of storms, including their passing over time, cloud top temperature, and associated precipitation, to identify their relationship with the size of the dead forests. We found that long-lived storms with thicker and tall clouds, result in bigger sizes of dead forest patches. Moreover, forests in the western Amazonia are more vulnerable to storms than forests on the other parts of the Amazonia.
My research explores how extreme storms impact tree loss in tropical forests, especially in the Amazon. These storms, responsible for 50-90% of annual rainfall in the tropics, often result in toppling trees, which disrupts the forest’s ability to store carbon, a crucial ability to fight climate change. Previously, these phenomena were studied separately, but my work connects them. By analyzing satellite data, I’ve started uncovering relationships between the characteristics of extreme storms and tree loss sizes. This understanding can improve climate models, providing more accurate predictions about our changing environment.
Our research delved into the relationship between large-scale storm systems known as mesoscale convective systems (MCSs) and the phenomenon of ‘windthrow’ – when storms uproot trees – in the Amazon rainforest. We examined 38 pairs of windthrow and their associated MCS events to identify the specific storm characteristics influencing the extent of windthrow. We found that MCSs with a longer storm duration tended to result in more extensive windthrow. We found a positive correlation between the storm’s duration and the area of forest affected. The depth of convection clouds within the storm also played a role. Deep convection caused larger windthrow across the entire Amazon. In contrast, shallow convection led to medium-sized windthrows in western Amazonia and smaller ones in central Amazonia. Interestingly, we observed that rainfall wasn’t uniformly distributed among forest disturbances of the same size, suggesting the need for more precise precipitation data to establish a clearer relationship with windthrow sizes. This study offers detailed case studies on windthrows and corresponding MCS features. It helps reduce the uncertainty of previous research due to data mismatches between MCSs and windthrows, offering fresh insights into how land and atmosphere interact. These findings are important for refining our climate models and, ultimately, our understanding of climate change impacts on the ecosystem.
Figure. The workflow of correlating a windthrow event on the land surface to its associated convective storm in the atmosphere using remote sensing images from both land and meteorological satellites. Image courtesy of Yanlei Feng.
Contact: Yanlei Feng (UC Berkeley PhD graduates, currently at Carnegie Institute for Science), email@example.com
This research was supported as part of the Next Generation Ecosystem Experiments-Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under contract number DE-AC02-05CH11231. We acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6. We thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the data and providing access, and the multiple funding agencies who support CMIP6 and ESGF.
Publication: Feng, Y., Negrón‐Juárez, R.I., Chiang, J.C. and Chambers, J.Q., 2023. Case studies of forest windthrows and mesoscale convective systems in Amazonia. Geophysical Research Letters, 50(12), p.e2023GL104395. https://doi.org/10.1029/2023GL104395