Finding Wildfire’s Fingerprint in the Atmosphere

27 January 2020

Published by https://eos.org/

GLOBAL –  Wildfires seem to be everywhere in the news lately. For those of us in the United States, and particularly in California, “wildfire season” evokes a clear sense of dread, having personally touched so many us. (I have several friends who lost homes—thankfully, though, nothing more—during the 2017 Thomas Fire in my hometown.) Last year, a public uproar ensued when photos of the burning Brazilian Amazon spread across Twitter and eventually to international news outlets. In Indonesia, ultrafine particles from agricultural practices that ignite peatlands have serious effects on the health of tens of thousands of people in the region each year.

The air is filling with smoke. Scientists, gratefully, are busy figuring out the answers to all our questions: What is the smoke made of, where is it all going, and just how bad is it? We’ve compiled this special issue of Eos to take a close look at the growing field of wildfire emissions research, pulling in experts from across a dozen disciplines of the geosciences. Find a complete list of our coverage in the sidebar at the right.

First, Ralph Kahn of NASA’s Goddard Space Flight Center offers us a critical global perspective on wildfires. An expert on aerosols and remote sensing technology, Kahn describes the many satellite instruments being used to study wildfire emissions today. Scientists are overcoming the disadvantages of observations from space from any one satellite (e.g., relatively low resolution, narrow observation bands, orbital paths that limit revisits) by combining data from what are now a wealth of instruments overhead. The gaps in these low-Earth-orbit observations of smoke plumes, in both spatial and temporal coverage, can also be filled in by chemical transport models; the models themselves can be constrained and validated by the observational data. With each pass overhead, our Earth observers are giving us a clearer picture of smoke emissions and how they travel through the atmosphere.

A major challenge right now is figuring out the effects of wildfires on global climate, and the reverse: the changing climate’s effect on wildfires. In our feature story, you’ll meet the FIREX-AQ team flying over the western United States in a DC-8, trying to collect enough information to more accurately incorporate fires into global climate models. It’s a Herculean job when one considers the wild variations of fires in size, biomass fuel, and, of course, whether they’re ignited by human or natural sources. Most models today don’t even attempt to incorporate them, but FIREX-AQ and several other teams in our feature story believe that understanding wildfires is crucial to truly understanding—and forecasting—our climate.

In a bit of respite from these disasters, read our news story about some habitat protection provided by our favorite dam builders. Ecohydrologist Emily Fairfax searched through records of forest fires in North America that occurred near beaver habitats and discovered that their dams acted as irrigation channels, keeping nearby vegetation insulated from the flames. Be sure to watch the stop-motion animation Fairfax created to illustrate the beavers’ influence on their wooded surroundings.

Come back to Eos.org for more articles as part of our wildfire emissions special coverage through February.

—Heather Goss (@heathermg), Editor in Chief