Resolving the 21st century temperature trends of the upper troposphere-lower stratosphere with satellite observations

Historically, observational information about atmospheric temperature has been limited due to a lack of suitable measurements. Recent advances in satellite observations provide new insight into the fine structure of the free atmosphere, with the upper troposphere and lower stratosphere comprising essential components of the climate system. This is a prerequisite for understanding the complex processes of this part of the atmosphere, which is also known to have a large impact on surface climate. With unprecedented resolution, latest climate observations reveal a dramatic warming of the atmosphere. The tropical upper troposphere has already warmed about 1 K during the first two decades of the 21st century. The tropospheric warming extends into the lower stratosphere in the tropics and southern hemisphere mid-latitudes, forming a prominent hemispheric asymmetry in the temperature trend structure. Together with seasonal trend patterns in the stratosphere, this indicates a possible change in stratospheric circulation.

Automated summary

Historically, limited measurements hindered our understanding of atmospheric temperature. However, recent satellite observations have provided new insights into the fine structure of the upper troposphere and lower stratosphere, which are crucial components of the climate system. These observations reveal a significant warming of the atmosphere, with the tropical upper troposphere warming by 1 K in the first two decades of the 21st century. The warming extends into the lower stratosphere, creating a prominent hemispheric asymmetry in temperature trends and a potential change in stratospheric circulation.