Advancing knowledge of Earth's thermosphere dynamics with new analyses of the existing and extended WINDII dataset

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The Earth's atmosphere is divided into regions; troposphere, stratosphere, mesosphere, thermosphere. The troposphere is the region where weather occurs while the thermosphere extends upward from 100 km. These regions may be characterized by their population of species, e.g. ozone in the stratosphere and atomic oxygen in the thermosphere, by their temperature and by their winds. Measuring the winds is the most challenging, and the first major initiative was with WINDII, a Wind Imaging Interferometer developed and built in Canada and flown on NASA's Upper Atmosphere Research Satellite, launched in 1991. WINDII was a new and innovative adaptation of the Michelson interferometer using a CCD detector that imaged the airglow occurring in the mesosphere and thermosphere, a photochemical sub-visual glow in the high atmosphere produced by the action of sunlight in the daytime, but persisting at night. The airglow occurs in sharp spectral lines, so tiny shifts in wavelength arising from Doppler effect caused by the wind are measured with the interferometer. WINDII discovered the presence of a huge atmospheric 24 hr tide (250 km/hr) near the equator at 100 km altitude, caused not by the moon's gravitation, but by solar heating; called a "migrating" tide because it moves with the sun. Strong dynamical motions from other waves were found over the entire globe, moving constituents, such as atomic oxygen, from place to place. WINDII celebrated its 20th anniversary last year, and then, with UARS, plunged into the Pacific Ocean. Just recently it has been discovered that there are also "non-migrating" tides, that do not move with the sun, but are driven by strong thunderstorm convection in the troposphere, propagating up to 250 km in the thermosphere. These are seen with WINDII as four wind waves around the Earth, three coming from the three continents and one from tidal propagation as seen from the satellite. The details of the character of these waves and the study of tropospheric effects reaching the thermosphere are the subject of this proposal. Knowledge of this transport of energy from the lower to the upper atmosphere will provide better atmospheric models in the future, for climate and weather prediction.