WINDII on UARS: A View of Upper Mesosphere and Lower Thermosphere Dynamics.

Abstract

WINDII, the Wind Imaging Interferometer on the Upper Atmosphere Research Satellite (UARS), has been in orbit since September, 1991 and by 1995 had accumulated more than 14 million images of the upper atmosphere. It employs Doppler imaging using a Michelson interferometer and CCD camera to obtain winds, temperatures and volume emission rates of selected airglow emissions in the visible and near-IR covering the altitude range 80 to 300 km. In this paper we first present wind and emission rate measurements from the O(1S) 557.7 nm night airglow emission resulting from the recombination of atomic oxygen. From these data atmospheric tides have been found to have a profound influence on the distribution of atomic oxygen. A strong longitudinal modulation in winds and emission rate has been found as well, indicating large scale planetary disturbances in atomic oxygen. Observations of daytime 557.7 nm green line emission are then presented, which arise mainly from solar EUV excitation. From these data one can see the response of the green line emission to the solar flux, as well as planetary scale disturbances. During the daytime, scattering from polar mesospheric clouds provides further evidence for the strong dynamics of this region of the atmosphere.

High‐latitude mesospheric mean winds: A comparison between Tromsø (69°N) and Svalbard (78°N)

“…Situating radar systems in polar regions presents obvious difficulties. Without using polar orbits and thus compromising low‐latitude and midlatitude coverage, remote sensing methods, like the WINDII and MLS instruments on the UARS satellite [e.g., Shepherd , 1996], cannot see further than around 75°N. Furthermore, the direct measurement of vertical motion is difficult and values tend to be deduced from convergence and divergence in the horizontal wind field, and thus the veracity of the deduced values is highly dependent on the observations' temporal and spatial resolutions.…”