The ionised trail
A meteoroid travelling at 11–72 km/s compresses and heats air in front of it, stripping electrons from atoms and creating a cylindrical plasma column tens of kilometres long. This column reflects VHF radio (30–50 MHz) almost perfectly for a fraction of a second. A radar ping detects the reflection and measures its Doppler shift.
Wind in the mesosphere
Commercial weather balloons stop at 30 km. Satellites look down from above 100 km. The mesosphere (50–85 km) was a blind spot until meteor radars filled it. By tracking how ionised trails drift, meteor radars map wind speed and direction at altitudes where no other sensor routinely reaches.
Gravity waves and climate
Atmospheric gravity waves — oscillations driven by buoyancy, not to be confused with spacetime ripples — transfer energy and momentum from the troposphere to the upper atmosphere. Meteor radars detect their breaking and dissipation, providing data for climate models that predict long-term trends in atmospheric circulation.
Global networks
Major systems include the SkiYMet network (operating since the 1990s), the AMBER system, and the upcoming NASA MEaDI project. Together they form a sparse but valuable global wind map at the edge of space, 24 hours a day, with no balloons and no satellites.