This is a 4-year project to investigate mid-latitude sporadic E layers, layer irregularities, and so-called quasi-periodic (QP) echoes using the Arecibo incoherent scatter radar, its instrument cluster, and a new coherent scatter imaging radar to be deployed near the University of the Virgin Islands (UVI) on St. Croix. A pilot study was carried out during the summer of 2002 which showed that the QP echoes arose from elongated, wavelike structures in sporadic E layers of the kind that has previously been observed at Arecibo and tentatively been associated with convection driven by neutral shear instabilities. Long-term, remote observations by the new autonomous radar in St. Croix will be used together with the Arecibo facility to assess the stability of the neutral mesosphere-lower-thermosphere (MLT) region, identifying the true cause of the layer structuring, and studying the plasma physics involved in producing the QP echoes.
Sporadic E layers and irregularities drastically affect HF and VHF radio wave propagation so the project also has space weather relevance. The project will bring educational experiences in upper atmospheric research to the diverse undergraduate student body at UVI, as well as to graduate students at Cornell and Clemson University. Furthermore, the imaging radar on St. Croix will become part of the Arecibo facility and add to the capabilities of the Incoherent Scatter Radar and optical instrumentation. It will add coherent scatter capabilities to the Arecibo Observatory instrument cluster, accessible by the community for studies of sporadic E, mid-latitude spread F, and meteor echoes, among other topics of general interest. This is a multi-institution proposal with co-investigators and students from Cornell, Clemson, and UVI participating.
