Instrument Cluster Studies of the Mesosphere and Lower Thermosphere at Arecibo

Instrument Cluster Studies of the Mesosphere and Lower Thermosphedr at Arecibo This award supports a three year program of continued comprehensive studies of mesosphere and lower thermosphere aeronomy. This program builds on the techniques and results of the 1989 AIDA (Arecibo Initiative in Dynamics of the Atmosphere) campaign and will utilize the radar and optical facilities of Arecibo Observatory as well as sodium and iron lidars from Penn State and/or the University of Illinois. Of particular interest are the apparently linked dynamical and chemical processes leading to the formation of ion, neutral sodium, and neutral iron layers in the 80-110 km height range. Additional interest centers on the origin of the 6-hour tide, the relationship of this tide with sporadic intermediate ionization layers, on the occasional unexplained occurrence of ion layers as low as 82 km altitude, and on convective processes as observed in the sodium layer. This research program will culminate in the proposed 1994 AIDA-LAMS (LAyers and MicroStructure) campaign which will utilize several radars and lidars as well as other instruments to investigate these and other phenomena. Several graduate and undergraduate students will be part of this research effort which also involves research residencies at the Observatory.