Assimilated observations of thermospheric winds, the aurora, and ionospheric currents over Alaska

We present simultaneous measurements of thermospheric winds, auroral emissi ons, and ionospheric currents over Alaska, obtained from four separate inst ruments. Thermospheric (F region) wind maps were recorded by an all-sky ima ging Fabry-Perot spectrometer located at Poker Flat and observing at lambda 630.0 nm. Auroral images at lambda 557.7 nm were obtained from the low-res olution visible imager on board the Polar satellite. White-light all-sky au roral images were recorded by ground-based all-sky cameras located in Alask a at Poker Flat (65 degrees 07'N, 212 degrees 34'E) and at Kaktovik (70 deg rees 06'N, 217 degrees 24'E). Finally, the east-west component of the ionos pheric F region plasma convection was inferred using the Alaskan meridian c hain of magnetometers. Montage images of these four data sets are presented , projected onto a geographic map of the Alaskan region. We examine a 10-ho ur period during the Alaskan local nighttime of February 10, 1997. These mo ntages illustrate a close relationship between spatial structures occurring in the aurora, in the ionospheric plasma convection, and in the F region w ind field. Latitudinal shear of the geomagnetic zonal wind, often observed in the premidnight time sector, was seen to be associated with both the equ atorward and poleward boundaries of the discrete aurora. We focus particula rly on a period commencing just after 0900 UT, when a strong shear in the z onal wind was observed to sweep southward across Alaska. After magnetic mid night the wind field was dominated by the emergence of the "cross-polar jet " from the polar cap. This overwhelmed any wind features associated with lo cal auroral processes.