Proceedings with Extended Abstracts (single PDF file) - Radio ...

Report on Session I.2 “D, E and F Region Coherent Scattering”Conveners: D. Hysell and R. PalmerAbstract: This session was devoted to theory and observations of coherent scatter fromionospheric irregularities at all latitudes. Reports pertaining to mature fields of study likethe auroral and equatorial electrojets, PMSE, sporadic E layers, and equatorial spread Fwere solicited. Recent and planned campaigns like SEEK II and EQUIS II attest to the factthat numerous problems remain unsolved in these areas. In addition, reports on emergingareas of research including long-lived meteor trails, 150 km echoes, daytime spread F, andmidlatitude spread F were sought. Also welcome were papers on new radar techniques thatcan promote rapid progress in these areas such as passive radar, distributed radar, andaperture synthesis imaging.Despite the breadth of the solicitation, most of the papers submitted to this session fell intoone of two categories: low- and mid-latitude E region irregularities and PMSE, indicatingwhere community interest is currently focused. The session was accordingly divided intotwo parts. The main findings of the respective parts are summarized below.E region irregularities: The first part of Session I.2 was chaired by D. Hysell and T. Ogawa.It opened with an invited presentation by J. Chau, D. Hysell, and M. Mila contrasting themorphology and climatology of E region echoes received at equatorial and mid latitudestations: Jicamarca and Piura. Much of the discussion concerned counter electrojetconditions which, although never observed prior to June, 2000 at Jicamarca, have beenobserved on seven occasions since. The observations revealed that counter electrojetirregularities appear only when large reversed zonal electric fields exist and that theirDoppler shifts obey a cosine dependence on zenith angle much like ordinary type 2 echoes.S. Fukao next presented an invited paper by M. Yamamoto and S. Fukao summarizingpreliminary results from the SEEK II rocket campaign conducted in Japan in August, 2002.Rockets launched during the campaign encountered multiple, steep, patchy sporadic Elayers with intense electric fields approaching 10 mV/m and embedded in sheared neutralflow. In a paper by S. Saito, S. Fukao, R. T. Tsunoda, et al., radar interferometry showedthat the quasiperiodic (QP) echoes detected during SEEK II arrived from localized, discretescattering patches drifting southwestward and maintaining altitude as they drifted. Thispicture was consistent with the one presented by G. C. Hussey, C. Haldoupis, and A.Bourdillon et al. who combined azimuth-time-intensity observations from the Valensoleradar in France with soundings from a CADI ionosonde to measure the wind-induced driftsof the sporadic E layer patches. In the invited presentation by C. Haldoupis, M. Kelley, G.Hussey, et al. that followed, the current status of mid-latitude sporadic E layer irregularitieswas summarized, and accumulating evidence of a connection to midlatitude spread F wasemphasized. C. Haldoupis argued that the intense polarization electric fields generated bypatchy sporadic E layers are, ultimately, the cause of F region upwelling and structuring.This novel concept led to a discussion of the roles of the E and F regions as sources andsinks of ionospheric instability. The subsequent paper by J. Urbina, E. Kudeki, and S.Franke discriminated between unstructured scattering layers and QP echoes at mid20