Speaker: Bernd Karcher (German Aerospace Centre)
Title: On contrail cirrus lifetimes
Abstract:
This talk presents a process-based investigation of lifetime statistics of persistent contrails and contrail cirrus clouds based on an idealized dynamical microphysical model. Cloud lifetimes are estimated by tracking the microphysical evolution of a cirrus layer that evolves in a large-scale ice-supersaturated area driven by a prescribed dynamical forcing. Special emphasis is given to the crucial role of internal high frequency gravity waves in affecting cirrus lifecycles. Simulated lifetime statistics are compared with satellite observations and categorized into three distinct evolutionary regimes. A parallel is drawn to cold cirrus at the tropical tropopause, for which unequivocal observational evidence is available, and implications for future contrail research are discussed.
Bernd Kärcher has been working at the DLR Institute of Atmospheric Physics since 1997 and has been an adjunct professor in the Faculty of Physics at the Ludwig-Maximilians University of Munich since 2006. He headed a number of cross-sectoral DLR projects on aviation and the climate. His main focus is the physics of clouds. His research work makes a significant contribution to identifying the key physical and dynamical processes involved in the formation of natural ice clouds (cirrus clouds) and contrail cirrus, modeling them and analysing the interplay of these processes in detail. The improved scientific understanding helps to identify the cloud-related climate effects of aviation using airborne measurements or remote sensing methods and represent them in climate models.