Quantifying Fire-Induced Surface Climate Changes in the Savanna and Rainforest Biomes of Brazil

Fernando De Sales

San Diego State University

Monday, Aug 12, 2024, 1:00 pm MT
DSRC Room GC402

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Abstract

In the first six months of 2024, the main Brazilian biomes broke records in the number of wildfires. The Cerrado (tropical savanna) has experienced the highest number of fire outbreaks ever recorded in the period since 1998, when the fires began to be monitored by satellites. In the Amazon rainforest, the number of fire outbreaks in the first half of 2024 has been the highest in the last 20 years. Long-term climate change projections indicate warmer and drier conditions in both biomes favoring longer and more intense fires.

This study uses a combined-research approach based on remote-sensing and modeling to quantify the effects of burned areas on the surface climate in both aforementioned Brazilian biomes. Our estimates indicate that between 2007 and 2020, approximately 6% of the savanna and 2% of the rainforest were burned on average. Non-parametric quantile regression analyses based on model simulations indicate that latent heat flux decreases on average by approximately 0.17 W m−2 in the savanna and 0.60 W m−2 in the rainforest per each 1 km2 burned, with most of the impacts registered during the onset of the wet season. Sensible and ground heat fluxes are also impacted but at less intensity. Near-surface air is warmer and drier, especially over the rainforest burned sites. Lastly our experiments indicate that fires reduce gross primary production in the savanna and rainforest by 12% and 10%, respectively.

About: My research aims at improving our understanding of the interactive processes between the biosphere and the land surface through observations, remote sensing, and numerical modeling. These processes regulate heat, moisture, momentum, and gas exchanges, which in turn help modulate temperature and precipitation regimes; and therefore, are strongly linked to a sustainable human existence. Funding agencies NSF and NASA.

Affiliation: Associate Professor of Climate Science, Geography Department, San Diego State University

Ph.D. University of California, Los Angeles (advisor: Dr. Yongkang Xue)
M.Sc. Universidade de São Paulo (2000)
B.Sc. Universidade de São Paulo (1998)