Comparisons of SABER Temperature Profiles With Rocket, Groundbased, and Satellite Measurements

The SABER instrument has been providing near global measurements of the mesosphere and lower thermosphere since early January 2002. An important goal of that experiment is to obtain the kinetic temperature profile into the lower thermosphere, where the retrieval is complicated by significant contributions due to non-LTE effects and a sharply decreasing CO2 mixing ratio. Non-LTE effects are most noticeable for high latitude summer because of radiative excitation of CO2 molecules at the cold mesopause by emissions from the much warmer stratopause and lower mesosphere. We will show LTE retrievals of temperature from SABER and compare them with correlative measurements from the ground-based sodium (Na) lidar and the falling sphere measurements obtained during the MAC-WAVE observing campaign in northern Europe in early July 2002. We also discuss comparisons with the UARS HALOE instrument. HALOE obtained sunrise profiles at 67 N on July 4. They show temperatures that decrease smoothly with altitude throughout the mesosphere, but with large variations occurring in a layer above the 0.01-hPa level. Some initial SABER comparisons with HALOE profiles for early March indicate good agreement in the retrieval of LTE temperatures for the stratosphere and mesosphere. A plot of the zonally-averaged, ascending minus descending orbital LTE temperatures from SABER for early March shows the signature of a diurnal tide clearly. At this time that result is based solely on the observed differences at each latitude and altitude for the two local times of the SABER measurements of early March. This approximate tidal amplitude reaches 15 K in the tropical middle mesosphere; larger amplitudes are found just below the tropical mesopause. Net tidal amplitudes for the middle latitudes are almost directly out-of-phase with and not quite half the magnitude of those at the Equator. Vertical wavelengths for these tidal variations are about 25 km at the Equator but closer to 30 km at 30 degrees latitude.