Sunday, July 25, 2010

Sharp Thunder

Sharp Thunder VBR MP3 200.4 kb, Sharp Thunder OGG format 112.8 kb which is a free, open standard container format maintained by the Xiph.Org Foundation. The OGG format is unrestricted by software patents and is designed to provide for efficient streaming and manipulation of high quality digital multimedia.

US Dept of Commerce, National Oceanic and Atmospheric Administration, National Weather Service. The information on government servers is in the public domain, unless specifically annotated otherwise, and may be used freely by the public.

Generally speaking, works created by U.S. Government employees are not eligible for copyright protection in the United States. See Circular 1 "COPYRIGHT BASICS" PDF from the U.S. Copyright Office.

The temperature of the atmosphere affects the thunder sound you hear as well as how far away you can hear it. Sound waves move faster in warm air than they do in cool air. Typically, the air temperature decreases with height. When this occurs, thunder will normally have an audible range up to 10 miles (16 km).

However, when the air temperature increases with height, called an inversion, sound waves are refracted (bent back toward the earth) as they move due to their faster motion in the warmer air. Normally, only the direct sound of thunder is heard. But refraction can add some additional sound, effectively amplifying the thunder and making it sound louder.

Graphic showing how refraction of sound leads to louder thunderThis is more common in the winter as thunderstorms develop in the warm air above a cooler surface air mass. If the lightning in these "elevated thunderstorms" remains above the inversion, then most of the thunder sound also remains above the inversion. However, much of the sound waves from cloud-to-ground strikes remain below the inversion giving thunder a much louder impact.

This audio is part of the collection: Community Audio
Artist/Composer: National Oceanic and Atmospheric Administration
Keywords: Thunder
Creative Commons license: Public Domain

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