Hydroxyl layer: trend of number density and intra-annual variability

摘要: Abstract. The layer of vibrationally excited hydroxyl (OH*) near the mesopause in Earth's atmosphere is widely used to derive temperature at this height and observe dynamical processes such as gravity waves. concentration OH* controlled by product atomic hydrogen, with ozone creating a enhanced region. However, basic influences on are oxygen temperature. long-term monitoring provides information changing atmosphere. It important know which proportion trend results from anthropogenic impacts reflects natural variations. In previous paper (Grygalashvyly et al., 2014), were investigated particularly midlatitudes basis our coupled dynamic chemical transport model LIMA (Leibniz Institute Middle Atmosphere). we consider for number density between years 1961 2009 analyze reason trends global scale. Further, intra-annual Temperature wind have strongest trend. Surprisingly, increase greenhouse gases (GHGs) has no clear influence chemistry OH*. main lies fact that, production term OH*, if hydrogen increases due increasing humidity middle methane oxidation, decreases. maximum found region very variable. intricate domain marked changeable dynamics strong gradients all chemically active minor constituents determining chemistry. responds, part, sensitively small changes these parameters. cause behavior given nonlinear reactions photochemical system being enforced oscillator driven diurnal-periodic solar insolation. At operates vicinity resonance. cycle mirrored data, but Lyman-α radiation small. shows distinct hemispheric differences. calculated values show sometimes step around certain year. We introduce method find out date discuss possible behavior.