How Cold Air Changes What You Hear in Denali

Deep in a remote park, away from the hum of daily life, you start to hear faint birdsong, insects and the crackle of leaves — and a droning plane overhead suddenly sounds startlingly out of place. But in mountain parks like Denali in Alaska, what you hear also depends on the weather. A 2024 study found that temperature inversions can change background sound levels dramatically.

Riley Creek contributes to the soundscape of the Triple Lakes Trail in Denali National Park. Credit: Chris Grahn, National Park Service.

Why parks measure sound

National Park Service scientists monitor, study and protect park sounds, for people and wildlife, as they would any other natural resource. Natural sounds — flowing water, changing weather — affect how much aircraft or vehicle noise is heard, so understanding how ambient sound varies helps researchers improve how they monitor it.

What inversions do

An inversion happens when warmer air sits on top of cooler air, trapping it below. In a subalpine valley in Denali, researchers found:

• Timing. Inversions happened more often between 7:00 p.m. and 9:00 a.m.
• Louder background. Strong inversions — where temperature rises more than 0.06°C per meter of height (about 0.03°F per foot) — raised sound levels by 10–15 decibels.
• Steadier soundscape. Inversions reduced the seasonal swings in sound levels, making it easier to predict and account for noise from sources like aircraft.

Inversions, the authors conclude, play a crucial role in shaping Denali's soundscape. The findings could help scientists design better ways to monitor and reduce noise pollution in similarly remote parks.

Sources

Based on "Changing Weather Influences What We Hear in Remote Areas," by the editors of Park Science, Volume 39, Number 1 (Winter 2024–25), "Research Roundup," National Park Service; a work of the United States government in the public domain. The study: Betchkal and Hug, 2024, "Influence of Atmospheric State on Variability of Long-Term Residual Ambient Sound Level Measurements in a Subalpine Valley," Journal of the Acoustical Society of America 156: 2877–2888.