National Park Service Soundscape Monitoring

Browse by Park


Spectrograms can be searched by any combination of the name of a national park, state, or year. Or leave the search box blank and click "Go" to see all available files. Your search will retrieve a single image for each monitoring site. Click on that image and scroll through the related spectrograms appearing in the far left column.

How to read a Spectrogram

Click here for example

National Park Spectrograms


Natural Sounds Program


For more than two decades the National Park Service and its contractors have conducted acoustical monitoring at park units throughout the United States. Most of this data has never before been widely accessible to the public, and the Western Soundscape Archive now makes available more than 10,000 spectral images from approximately 200,000 hours of park service sound level monitoring.

Each spectral image, or "spectrogram" is a 24-hour picture of the sounds of an area. The images allow rapid visual assessment of daily acoustic patterns and show the prevalence of many kinds of sound sources, such as aircraft, bird songs, insect choruses, rain, wind, river flows and the environment in general. Such sound signatures can offer clues about an area's biodiversity and ecological health, and are also a window into the increasing impacts of human-caused noise on the environment.

See example spectrograms below. Click to enlarge.

annotated spectrogram

An annotated spectrogram courtesy of the National Park Service

annotated spectrogram from the National Park Service

This is an example of a 24-hour picture of sounds from Pasture Wash, Grand Canyon National Park. Selected aircraft overflight events are annotated. The Park Service has also identified the sounds of a coyote chorus at approximately 0230 and the dawn chorus of birds that extends from approximately 0500 to just after 0800.

unweighted spectrogram

Each spectrogram will be presented in two different forms. One version, such as the spectral image in this example, represents sounds that are heard within the range of human hearing. The other version (see slide below) shows the full spectrum of the recording.

spectrogram from Pasture Wash

An "unweighted" spectrogram not corrected for human hearing.


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