July 31, 2017 | Climate research in the stratosphere

High altitude research aircraft investigates particle layer above Asia

  • Aerosol cloud above Asia at an altitude of up to 17 kilometres affects the climate
  • M55 Geophysica high altitude research aircraft carries out measurements from Kathmandu for the first time
  • 37 scientific organisations from 15 countries participating
  • Focus: Aeronautics, Climate research

It is one of the big unknowns in climate research. The aerosol cloud that sits above the Asian summer monsoon consists of small droplets and dust particles that reach an altitude of up to 17 kilometres and have an effect on the climate. With the participation of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and under the leadership of the Alfred Wegener Institute (Alfred Wegener Institute (AWI)), an international team of scientists is currently investigating the atmosphere above Nepal with a high altitude research aircraft. The Russian M55 Geophysica research aircraft took off for its first measurement flight in the Asian stratosphere on 27 July 2017. "We plan to carry out a detailed investigation of the composition of the air masses in the Asian monsoon region at an altitude range of 12 to 20 kilometres," says DLR atmospheric researcher Hans Schlager. "Of particular interest to us here are the sources of the aerosol layer that has previously only been observed by satellites."

Gigantic air elevator

During summer, the Asian monsoon affects weather patterns over the entire northern hemisphere. It acts like a giant elevator, carrying vast amounts of air and pollutants up to an altitude of over 16 kilometres, which reach the stratosphere, the level of the Earth's atmosphere where the ozone layer is situated. In the stratosphere, monsoon air spreads around the world and persists for years. Satellite images show a thin cloud of aerosols directly above the monsoon-affected region that stretches across southern Asia – from the Arabian peninsula to the east coast of China.

Scientists from the DLR Institute of Atmospheric Physics studied the presence of aerosol precursor gases, especially sulphur dioxide and nitric oxides, in the upper air layers. "We installed two complex, fully automated measuring instruments on the Geophysica high altitude research aircraft," explains Schlager. "We also developed an ion and trace gas mass spectrometer for this research campaign."

Small particles that affect the climate

Aerosols may either warm or cool Earth's surface depending on their composition and how they interact with cloud formation processes. The climatic effect of aerosols is one of the great uncertainties in climate change forecasting. "The origin and composition of aerosol clouds above monsoon-affected regions and the processes that lead to their formation is a major current focal point in atmospheric research," says Schlager. "We still do not know how the monsoon system reacts to changes in the emission of air pollutants or climate change."

The international team of scientists in the StratoClim project aims to close this knowledge gap. A total of 37 scientific organisations from 11 European countries, as well as from the United States, Bangladesh, India and Nepal, are collaborating on this. Project leader Markus Rex from the AWI is delighted: "For the first time we will be able to study the composition of the air that reaches the tropopause region and the stratosphere above the monsoon."

Following years of effort by various international research teams and numerous failed attempts, the consortium succeeded in gaining access to the unique airspace above the Himalayas and carrying out measurements with the M55 Geophysica in Nepal, India and Bangladesh up to an altitude of 20 kilometres. The first measurement flight on 27 July 2017 is the first of a series of nine research flights that will take place in this region until mid-August and will be accompanied by measurements using high altitude research balloons launched from Nepal, Bangladesh, China, India and Palau.

StratoClim research project

The StratoClim research project (Stratospheric and upper tropospheric processes for better climate predictions) is funded by the European Union. The main objective of the project is to produce more reliable projections of climate change and stratospheric ozone by improving the understanding of key processes in the Upper Troposphere and Stratosphere (UTS). In addition to DLR, more than 30 research institutes and universities from 15 (mainly European) countries are involved in the project, under the aegis of the AWI.


Manuela Braun

Editor HR
German Aerospace Center (DLR)
Central HR Marketing
Münchener Straße 20, 82234 Weßling

Dr Hans Schlager

German Aerospace Center (DLR)
Institute of Atmospheric Physics
Institute of Atmospheric Physics
Münchener Straße 20, 82234 Oberpfaffenhofen

Sebastian Grote

Alfred Wegener Institute (AWI)
Communications and Media Relations
Am Handelshafen 12, 27570 Bremerhaven