Atmospheric Measurement techniques.

Advances in ionospheric and atmospheric measurement techniques will allow a detailed analysis of the effect of the '99 eclipse.

• Global Atmospheric modelling has been used to study the effect of an eclipse on the upper atmosphere. This enables us to make testable predictions about the effect of the eclipse on our upper atmosphere.



• Ionospheric Tomography will be used to study the effect of the eclipse on the distribution of ionisation. According to modelling work, it should be possible to see waves generated by the eclipse in these scans.



• Fabry Perot Interferometers and related instruments will be able to measure the effect of the eclipse on both the temperature and movement of the atmosphere.



• Vertical sounding of the ionosphere. Ionosondes will be deployed to study changes in the ionosphere. Modern ionosondes can not only measure the electron density, but can also obtain information about the spatial distribution of irregularities. This enables the instrument to detect waves as they propagate through the atmosphere, altering the shape of the ionosphere as it does so.



• Oblique sounding uses similar technology to vertical sounding, but spaces the transmitter and receiver apart by anything from ten to several hundred kilometers. Oblique propagation has direct implications to radio communications.



• The Solar Heliospheric Observatory, SOHO , will be in a position to make in-situ measurements of the active regions on the solar disk and lower atmosphere of the sun. We propose to use this information in conjunction with ionospheric measurements to carry out a detailed analysis of ionospheric loss rate during an eclipse.



• The meteor radar bounces radio signals off the trails of meteors as they burn up in the atmosphere. These trails are blown about by the winds and so by measuring the speed with which these trails move, it is possible to infer the wind speed.