Programme Atmosphere and Climate (ATMO)

PT4. Composition and dynamics of the upper troposphere and middle atmosphere

In Programme Topic 4 we investigate the composition and dynamics of the upper troposphere and middle atmosphere.
 Ozone depletion; IMK-ASF, KIT; Sinnhuber et al. 2011; Geophysical Research Letters, volume 38, more information: doi:10.1029/2011GL049784

The region of the upper troposphere and middle atmosphere plays an important role in the climate system. This atmospheric region impacts on surface climate via radiative effects and dynamical couplings.

Changes in temperature as well as in distributions and concentrations of radiatively active gases (greenhouse gases), and the abundance of cloud particles in the upper troposphere - lower stratosphere (UTLS) result in particularly large changes in the atmospheric radiative forcing. Consequently, surface climate exhibits a large sensitivity to temperature and composition changes in the UTLS.

 

Our research focuses on

  • stratosphere-troposphere exchange
  • cirrus clouds
  • ozone-climate interactions
  • dynamic couplings
  • large-scale processes, variability and trends

Our aim is

  • to quantify key physical and chemical processes in the upper troposphere and middle atmosphere by utilizing integrated measurement systems covering global to local scales
  • to improve climate projections by a better representation of these key processes in chemistry-climate models

 

 

 

Subtopics

CLaMS simulation of CO in ca. 18 km altitude in the Asian monsoon ©S. Ploeger Atmos. Chem. Phys., 15, 13145-13159, 2015 www.atmos-chem-phys.net/15/13145/2015/ doi:10.5194/acp-15-13145-2015

 

Figure: Ploeger et al. 2015

ST1. Stratosphere-troposphere exchange

We deploy data collected on research and passenger aircraft combined with state-of-the art Langrangian (CLaMS) and Eulerian (COSMO...) models to study bidirectional stratosphere-troposphere exchange especially in the radiatively crucial altitude range of ~6 to ~20 km.

Contributing institutes:

 

 

Anvil outflow of a tropical convective system sampled during the HALO-Mission ACRIDICON-CHUVA 2014 in the Brasilian Amazon.; Photo: DLR (CC-BY 3.0)

 

Photo:DLR(CC-BY 3.0)

ST2. Cirrus clouds

Upper tropospheric cirrus ice clouds influence the climate because they reflect the incoming sunlight and absorb the outgoing radiation emitted by the Earth. We investigate cirrus formation and properties based on laboratory as well as atmospheric observations. We contribute to the development of parametrizations required to estimate the role of cirrus clouds in the Earth's atmosphere with global climate models.

Contributing institutes:

 

 

 

 

HALO research aircraft; Photo: DLR

 

Photo: DLR

ST3. Stratospheric ozone and climate change

The evolution of the stratospheric ozone layer during the 21st century will be strongly influenced by trends in temperature and circulation along with atmospheric composition change due to increasing concentrations of greenhouse gases. We study the chemical and physical processes affecting the stratospheric ozone layer by satellite remote sensing measurements, numerical modelling, field campaign observations and laboratory experiments. We also investigate the possible impacts of proposed "climate engineering" measures on the ozone layer.

Contributing institutes:

 

 

 

 

 

 

Figure: Preusse, FZJ

ST4. Dynamic couplings

The atmosphere impacts on surface climate via radiative and dynamical processes. In particular there is growing evidence that dynamical couplings in the middle atmosphere - troposphere system have a significant impact on regional weather patterns and climate. We study atmospheric wave dynamics based on high spatial resolution temperature observations by satellite instruments and radio occultation measurements. We derive gravity wave parametrizations for Medium-Range Weather Forecasts models and examine the impact of different parametrizations on climate simulations.

Contributing institutes:

 

 

 

 

 

 

 

COS distribution measured by MIPAS betw. Dec and Feb. 2001-2012; Glatthorn et al. 2015; DOI: 10.1002/2015GL066293

 

Figure: Glatthor et al. 2015

ST5. Trends, variability and large-scale processes

We investigate the trends and variability of atmospheric trace species and the underlying large-scale processes from the upper troposphere up to the thermosphere. Our research is mainly based on global satellite data such as those provided by the Michelson Interferometer for Atmospheric Sounding (MIPAS) onboard Envisat. The goal is to obtain knowledge about stratospheric and mesopheric circulation patterns and mixing and about feedbacks between circulation and chemistry.

Contributing institute: