Continuous operation of the FLATLAND ST (stratosphere-mesosphere) radar administered by NOAA is maintained at the Bondville Field Station. The FLATLAND radar, operating at a frequency of 50 MHz, has been designed to investigate the dynamics of the atmosphere above a plain area with insignificant orographical forcing. The routinely measured reflectivity profiles and Doppler spectra are collected in a NOAA database. Joint measurements with the Urbana Field Station MST radar are performed to investigate the horizontal scale lengths of atmospheric gravity waves and to follow the transit of weather fronts.

The 50 MHz Jicamarca Radio Observatory located near Lima, Peru, is used to investigate the structure and dynamics of the equatorial ionosphere. In the mesosphere ion ospheric D region, investigations aim to resolve the internal structure of narrow echoing layers and determine the relevant scattering/reflection mechanisms. In the higher ionosphere, E- and F-region plasma drifts, instabilities, and turbulence are under study. Current projects include efforts to quantify the anisotropies of equatorial plasma turbulence, obtain interferometric images of plasma irregularity structures, and measure the component of ionospheric drifts in the geomagnetic field direction. Major research effort is dedicated to the refinement of radar techniques suitable for these studies.

This is a three-year project funded for stratospheric and mesospheric wind and momentum flux deposition measurements using the 50 MHz radar facilities at the Jicamarca Radio Observatory located near Lima, Peru. The measurements are to be conducted during six 10-day campaigns planned for the 1993=N1995 period. The radar measurements will be used to investigate the enegetics and coupling of various wave motions in the equatorial middle atmo sphere and their influence on the mean flow.

This grant concerns the operation of an ST radar at the university's Sidney Field Station. Tropospheric and stratospheric wind, reflectivity, and aspect sensitivity measurements to be conducted with the Sidney radar will complement similar measurements conducted by similar radars operated at the Urbana Atmospheric Observatory and Bondville Field Station. The three-radar network will be used in correlative studies of atmospheric gravity wave propagation in the troposphere and the lower stratosphere as well as phenomena associated with the evolution and dynamics of weather fronts.