page_title: Weather radar
section_title: Meteorite fall detection
hierarchical_section_title: Weather radar / Specialized applications / Meteorite fall detection
caption_attribution_description: English: NOAA NEXRAD radar image of meteorites falling in the Park Forest, IL meteorite fall of 26 March 2003
context_page_description: Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type. Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather.
  During World War II, radar operators discovered that weather was causing echoes on their screen, masking potential enemy targets. Techniques were developed to filter them, but scientists began to study the phenomenon. Soon after the war, surplus radars were used to detect precipitation. Since then, weather radar has evolved on its own and is now used by national weather services, research departments in universities, and in television stations' weather departments. Raw images are routinely used and specialized software can take radar data to make short term forecasts of future positions and intensities of rain, snow, hail, and other weather phenomena.
context_section_description: At right, an image showing the Park Forest, Illinois, meteorite fall which occurred on 26 March 2003. The red-green feature at the upper left is the motion of clouds near the radar itself, and a signature of falling meteorites is seen inside the yellow ellipse at image center. The intermixed red and green pixels indicate turbulence, in this case arising from the wakes of falling, high-velocity meteorites.
  According to the American Meteor Society, meteorite falls occur on a daily basis somewhere on Earth. However, the database of worldwide meteorite falls maintained by the Meteoritical Society typically records only about 10-15 new meteorite falls annually
  Meteorites occur when a meteoroid falls into the Earth's atmosphere, generating an optically bright meteor by ionization and frictional heating. If the meteoroid is large enough and infall velocity is low enough, surviving meteorites will reach the ground. When the falling meteorites decelerate below about 2–4 km/s, usually at an altitude between 15 and 25 km, they no longer generate an optically bright meteor and enter "dark flight". Because of this, most meteorite falls occurring into the oceans, during the day, or otherwise go unnoticed.
  It is in dark flight that falling meteorites typically fall through the interaction volumes of most types of radars. It has been demonstrated that it is possible to identify falling meteorites in weather radar imagery by different studies. This is especially useful for meteorite recovery, as weather radar are part of widespread networks and scan the atmosphere continuously. Furthermore, the meteorites cause a perturbation of local winds by turbulence, which is noticeable on Doppler outputs, and are falling nearly vertically so their resting place on the ground is close to their radar signature.
caption: NOAA NEXRAD radar image of the Park Forest, IL, meteorite fall of 26 March 2003.
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