Abstract

The upper troposphere/lower stratosphere (UTLS) is believed to exhibit a very high potential for significant chemistry-climate feedbacks. In this talk I will review the UTLS characteristics that make this region important for chemistry-climate coupling and summarize what is known about potential feedback mechanisms. The most prominent UTLS characteristics have been discovered in studies using aircraft, balloon, and satellite measurements, which were challenging due to prevailing local conditions such as low temperatures and pressures but also high dynamical variability and occurrence of clouds. Using the example of the Earth-Explorer 7 mission candidate PREMIER , I will illustrate that further advances in our knowledge can still be expected. The investigation of feedback mechanisms on the other hand heavily relies on the use of chemistry-climate models, which in recent years have greatly increased our knowledge of the role of the UTLS in chemistry-climate coupling. Examples shown will include the impact of a changing climate on the distributions of radiatively active gases and its consequences for the troposphere.