A study published recently in the Journal of Geophysical Research: Earth Surface reports on a new technique that can be used to improve wildfire predictions. The technique looks at rock weathering and water storage in hills as clues for understanding risks of wildfires as well as landslides.
Led by Michelle Pedrazas of The University of Texas at Austin, the study is the first to analyze weathering patterns in hills and valleys at a deeper level – literally. Most computer models focus on soil level analyses, but this one also looked at the near-surface layer that includes trees, soils, weathered rock, and fractures, a layer called the "critical zone”.
"This study helps to unravel a mystery in the critical zone research community, the linkage between bedrock weathering, topography, and storage of water in mountainous watersheds," said Eric Pierce, the director of the Environmental Sciences Division at Oak Ridge National Laboratory.
"There's a lot of momentum to do this work right now," adds study co-author Daniella Rempe, an assistant professor at the UT Jackson School of Geosciences Department of Geological Sciences. "This kind of data, across large scales, is what is needed to inform next-generation models of land-surface processes."
The team’s analysis found deeper weathering and fracturing in hilltops and thinner weathering in valleys. They also saw weathering at deeper depths shorter hill slopes compared to taller ones. “Our findings provide evidence for feedbacks between erosion and weathering in mountainous landscapes that result in systematic subsurface structuring and water routing,” the authors write.
These findings are part of the puzzle of understanding the relationships between rock weathering and rock moisture, information that can be used to predict the impacts of droughts and subsequent wildfires.
"We were really seeing the potential impact of our research, [the importance of] where is the water, and when are trees really going to dry up, and what risk that is for society," Pedrazas concludes.