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Dynasonde: an Advanced Instrument for Ionospheric Exploration
Real-time data analysis by Dynasondes on the Web
Bear Lake Utah Dynasonde Web presentation at NGDC
Tromsų Norway Dynasonde Web presentation at EISCAT
What is a Dynasonde?
Pulsed radio waves of up to ~ 20 MHz (15m wavelength) may be totally reflected by the ionosphere, giving strong echoes even with rather low transmitted power (a few kW). This is the fundamental principle of the 'ionosonde'. The reflection process is strongly 'dispersive', or frequency-dependent, each frequency being reflected by one, two, or even three specific ionization densities, because the ionized plasma is 'magnetoactive'. Many properties of an echo (its travel time, phase-path, polarization, direction of arrival, amplitude and Doppler ... and even the distribution of these properties within the echo) are significantly modified by ionospheric properties near the reflection level and, to a progressively lesser extent, by the entire ionospheric path below reflection. Among the ionospheric properties are varying solar, auroral, meteoric and other ionization production sources, chemical reactions by which ionization returns to the neutral state, motions induced by winds, turbulence and electric fields, all resulting in very wide spectra of spatial irregularities and motions. Thus, by careful and complete measurement of radio echo properties, a wealth of information becomes available for diagnostics of the ionospheric processes. The Dynasonde evolved at NOAA between 1970 - 1980 as "an ionosonde competent to measure the dynamics of the ionosphere". A few hardware upgrades and continuing software development have maintained the several operating Dynasondes at a 'state of art' functionality.
Active Dynasonde Locations
The Future of the Dynasonde idea
Last Edited on: Wednesday, April 16,
2003 12:35 -0700
