The Doppler Rayleigh lidar system at Arecibo

The instrument structure and the operation of a Doppler Rayleigh lidar located at the Arecibo Observatory in Puerto Rico are described. The device consists of an injection seeded, frequency doubled, Nd:YAG laser coupled with a small Newtonian telescope and a single etalon, Fabry-Perot interferometer in its receiver. With this combination of transmitter and receiver, observations of the Doppler spectral components of the Rayleigh backscattered signal from the atmosphere are possible. Neutral wind and temperature up to mesospheric heights are presented. The improvements to the instrument that are underway, which will allow an increase in the temporal and spectral sampling of the winds, are discussed     

Middle-atmospheric Doppler lidar using an iodine-vapor edge filter

We present both modeled capabilities of and experimental data from a Doppler lidar for the stratosphere and the lower mesosphere that uses the edge of a molecular iodine filter in a differential measurement to provide frequency discrimination. Modeled results show a capability for wind measurements to an altitude of 55 km with 1.5-km resolution in 30 min. Experimentally, wind-vector components from 18 to 45 km are measured every 20 min. The molecular-vapor filter provides great advantages with regard to system stability, operation in less-than-optimum weather conditions, and simplicity of data analysis.     

The structure of electromagnetic wave-induced 557.7-nm emission associated with a sporadic- E event over arecibo

We report observations of electromagnetic wave-induced 557.7-nm emission in correspondence with a sporadic low-altitude plasma layer (the sporadic- E layer, E(s)). We show that the structure of 557. 7-nm emission seen for some events results from a transformation of transmitted energy by ionization clouds, compiling the patchy type E(s), and presents a projection of the sporadic- E layer structure on the emission altitude. This allows us to propose the first method for visualizing a horizontal structure of sporadic- E layers.