Recent research from Washington University in St. Louis has shed light on the significant role that dark-brown carbon (d-BrC) plays as a snow-warming agent in the aftermath of wildfires. This type of carbon, which is light-absorbing and water-insoluble, has been found to be 1.6 times more potent than black carbon, previously thought to be the main driver of snow melting. While the deposition of water-insoluble organic carbon on snow has been observed in various regions, the specific effects of d-BrC had not been thoroughly investigated until now.
Researchers liken d-BrC to the “evil cousin” of black carbon, as both types of particles are deposited onto snow surfaces in a similar manner. However, unlike black carbon, d-BrC cannot be easily washed away or bleached, making it a persistent snow-warming agent. As these particles darken the snow and reduce its reflectivity, the surrounding air temperatures increase, perpetuating the warming cycle. By overlooking the contribution of d-BrC, previous studies may have underestimated the extent of snow melt caused by wildfire smoke deposition.
Understanding the impact of d-BrC on snow melt is crucial for developing more accurate climate models and measurements. As wildfires continue to grow in size and frequency, policymakers will need to address the mitigation of this form of carbon to prevent accelerated snow melt. Despite d-BrC absorbing slightly less light than black carbon, its higher abundance in wildfire plumes makes it a significant factor in snow warming effects.
Experimental Approaches to Studying Snow-Aerosol Interactions
To further investigate the real-world effects of d-BrC, researchers at WashU will be conducting experiments using a specialized snow globe in the lab. By atomizing water droplets into the chamber and depositing aerosols on the snow surface, they aim to replicate the conditions of wildfire smoke deposition on snow. This experimental approach will provide valuable insights into the mechanisms behind snow melting due to aerosol particles.
The findings of this study highlight the importance of considering the role of d-BrC in snow warming effects caused by wildfires. By uncovering the unique properties of this type of carbon and its impact on snow reflectivity, researchers are paving the way for more accurate climate predictions and informed policy decisions to mitigate the consequences of wildfire-induced snow melt.