Similarities in middle atmosphere structures

Abstract

Similarities of middle atmosphere structures are analyzed on the basis of CRISTA and SABER data which extend from the upper troposphere up into the lower thermosphere. An event of planetary wave breaking is identified that leads to the formation of a surf zone the middle mesosphere (70 km); its structures are seen in temperature, potential vorticity and trace gas mixing ratios. A second analysis compares the structures of the tropopause and the mesopause. A cold point mesopause and a dynamical (potential vorticity) mesopause are suggested similarly as they are used at the tropopause. A lapse rate mesopause, however, appears to be of little use. The dynamical mesopause appears to indicate a transport barrier similar as it is the case at the low altitudes. In summer a "split mesopause" is observed at middle to high latitudes. There is a zonal wind jet near to this apparent mesopause break which is similar to what can be observed at the tropopause.