| The Wind Imaging Interferometer (WINDII) on board the Upper Atmosphere Research Satellite measures winds from the Doppler shifts of five different emissions from the thermosphere and upper mesosphere. As part of the measurement process the volume emission rate (photon cm−3 s −1), is accurately measured.;This includes the atomic oxygen O(1S) emission at 557.7 nm, which during the daytime is emitted over a large altitude range from about 85 to over 250 km. Two distinct peaks in altitude are formed, one near 100 km (lower thermosphere) and one near 145 km (middle thermosphere). Each involves very different production processes, so while both respond closely to solar variability effects, each is responding to different components of the solar spectrum.;The correlation of these two emission regions with different solar indices is presented, for both daily averages and for short term variations that include solar flares, which strongly (and only) affects the lower thermosphere peak. Relevant atmospheric processes including the influences of planetary waves that may impact upon the determination of solar variability are also described. |
