Simultaneous measurements of large vertical winds in the upper and lower thermosphere

High resolution vertical wind measurements of the upper and lower thermosphere were made at Poker Flat, Alaska, using a scanning Fabry-Perot spectrometer (FPS). Observations of the λ558 and λ630 nm emissions of atomic oxygen were made on 21 nights and allowed for the simultaneous determination of wind and temperature at altitudes of about 130 and 240 km, respectively. On two occasions, significant upwelling events were measured which lasted between 15 and 25 min. Peak velocities were up to 42 m/s at 130 km and 138 m/s at 240 km. Auroral activity was monitored using a meridian scanning photometer (MSP). On both occasions, the region of upwelling was located on the poleward side of the auroral oval during geomagnetically active conditions. A schematic model is used to describe an event from which the horizontal scale of the upwelling region is estimated to be less than 320 km in the lower thermosphere and less than 800 km in the upper thermosphere.