Studies for Mesopause Temperature Distribution Characteristics Based on the Sodium Lidar Data

As the boundary of mesosphere and thermosphere, mesopause is an important area for studying the middle and upper atmosphere, many energy coupling processes happen here, study for the temperature distribution characters will improve our understanding of the climatology of this region. This paper studies the annual and seasonal temperature distribution characteristics based on the Langfang sodium lidar data in 2013. Results show that, the annual mean mesopause locates at around 97.5 km with the temperature 191.2 K. Under the influence of exothermic chemical reactions, there is a relative maximum temperature 198 K at 91 km on the annual profile. The seasonal temperature at mesopause region is influenced by solar radiation and atmospheric dynamics. In winter, solar radiation is the primary factor, producing a higher mesopause of 181 K at 99 km altitude. In summer, the rising atmosphere from lower altitude makes a colder mesopause at 88 km altitude with the temperature 177 K. Harmonic analysis demonstrates a strong change in annual amplitudes over a rather small altitude range, coupling with the annual phase profile, and it is shown that dynamics in lower mesopause region and solar radiation in upper mesopause region play the key role in determining the thermal structure respectively.