The observations of O2*, O*, Na and OH* airglow emissions is a tool extensively used to infer temperatures at mesopause height and information about dynamical processes, such as gravity waves, planetary waves, and tides. Moreover, the airglow measurements are used to determine atomic oxygen, ozone, and atomic hydrogen which are very difficult to measure by other methods, and, in perspective, can be used to retrieve the chemical heating rate from the most significant exothermic reaction in the mesopause and water vapor. A number of investigations, which based on airglow measurements, are focused on temperature trends. Recently, airglow emissions were detected on Mars and Venus that give rise new abilities.
In spite of large application, less attention was devoted to parameters of the airglow layers such as thickness, altitude, and number density. Concerning the airglow layers a number of questions arise. How do the altitudes of the layers change? How do the intensities (number density) change? Which variations in temperature corresponds to the layers variations? How do the variations depend on the Lyman-alpha variation? How much of the variation is dependent on chemistry, dynamics and the Lyman-alpha, respectively? What is the relative behavior of the layers? What are the dependences between the heights and intensities of the emissions (number densities) of the layers? These questions can be asked about the variation of height, number density, thickness, and corresponding temperature in the framework of seasonal-latitudinal, short-term, and long-term variability. The questions on formation-relaxation processes of the airglow layers are represent an additional field of interest.

Solicited people: Alexander Feigin, feigin@appl.sci-nnov.ru; Valentine Yankovsky, valentine.yankovsky@spbu.ru; Tom Slanger, tom.slanger@sri.com