Virtual Observatory of the Alps

Linking the high altitude research stations in the Alps

Environmental Research Station Schneefernerhaus

Main Topic I

 

Atmospheric variability and trends

The atmosphere is a complex system. It is characterized by a variety of chemical, dynamic and radiation-related processes. Our knowledge about these processes is still incomplete. Therefore, forecasts about climatic development are still quite uncertain. Improved measurement and analyzing techniques should fill these gaps

Within this main topic, scientists focus on the following questions within the framework of three subprojects: How does atmospheric water vapor influence our climate? How does the concentration of further greenhouse gases like carbon dioxide or methane change? What's the matter with aerosols? The Alpine region influences the flow properties in the atmosphere, because of its complex topography. Due to the atmospheric overflow of the Alps, so called gravity waves are generated. Those comparatively small-scaled waves influence the large-scaled atmospheric flow systems stronger than expected. Therefore, the question is analyzed, how the structure function of such gravity waves look like in the Alpine region. 

 

Subprojects

TPI/01: Experimental climatic research to analyze interactions between water vapor, clouds, temperature and radiation in the Alpine region

TPI/02: Trends of gases and aerososl that have an impact on the climate and spatiotemporal deposition of persistent environmental pollutants

TPI/03: The Alps - homogenous source of atmospheric dynamic in climate model? Transnational studies of dynamic of atmospheric waves in the mountains (LUDWIG)

 

TPI/01: Experimental climatic research to analylze interactions between water vapor, clouds, temperature and radiation in the Alpine region

Water vapor contributes significantly to the atmospheric greenhouse effect, because it interferes in the earth´s radiation budget like no other trace gas and influences thereby the temperature. The sunrays warm up the surface of the earth. As a consequence, the surface emits long-waved radiation into the atmosphere. Just a part of this infrared radiation gets into the space, because it is partly absorbed by atmospheric water vapor. The air, that is thereby heated, emits thermal radiation back to the earth ("atmospheric back radiation") and consequently the temperature increases. The more heating of the earth, the higher increases the concentration of water vapor in the atmosphere. Thus, also the atmospheric back radiation increases (water vapor feedback). This process enhances the greenhouse effects, in case additional cloud formation and precipitation are not counteracting. In which dimensions will water vapor enhance the greenhouse effect and change our climate? Scientists under the leadership of the Karlsruhe Institute of Technology (KIT) at the location Garmisch-Partenkirchen focus on this topic.

 

Experiments to improve climate models

In this subproject, a so-called "radiation-closure-experiment" is performed at the Zugspitze location. Here, radiation codes are applied, that are used in these climate models, to simulate the atmospheric back radiation. These simulations are based on optical remote sounding measurements of the most important influencing variables (water vapor and temperature profile, microphysical properties of ice clouds). They are compared to simultaneous direct measurements of spectral infrared radiation. If there are any differences detectable in this comparison (means the "closure" fails), this indicates quantitatively an error of the radiation codes that can be corrected subsequently. In addition, existing long-term remote sensing measurement series with regard to trends in water vapor should be evaluated. Besides trends of water vapor, the main focus is on the trends of water vapor in height regions that are especially difficult in climate issues of the lower stratosphere.

 

TPI/02: Trends of gases and aerosols that have an impact on the climate and spatiotemporal deposition of persistent environmental pollutants

The chemical and physical condition of the earth´s atmosphere plays an important role in the observation and research of climate change. Locations in the high mountain region are particularly well-suited. They are far away from large cities and metropolitan areas. Thus, such locations generate more representative measurement conditions than the valley, which results in a greater reliability and significance of the measurement results. This applies for long-term acquisition of metrological measurement series, which describe the climate budget, for the trend climate-related trace gases and aerosols, as well as for environmental pollutants like pesticides, industrial chemicals and products of combustion. The aim of this subproject is to provide secure statements about the development of these measured quantities.

Those statements form the basis for a more precise forecast of the development of the climate and secure the registration of changes in chemical environmental pollution like air quality in central Europe.

Therefore, scientists of the German Meteorological Office at the Hohenpeißenberg and the Federal Environment Agency at the Zugspitze, as well as the Helmholtz Center Munich, generate long-term measurement series. Within the scope of the cooperation in the international VAO project, the time series will be analyzed in comparison to other central European Alpine locations in Germany, Austria, Switzerland, Italy and Bulgaria.

The consequent and continuous protection of the data quality objectives in the framework of this project is the main prerequisite for a worldwide comparability on a high standard. The measurement series should be published regularly on the website of the Alpine data analysis center AlpEnDAC. In this way, the environmental policy can react on changes quickly and control the climate protection measures as well as the implementation of the Stockholm convention. This convention comprises international prohibitions and restrictions with respect to generating and applying selected persistent environmental pollutants.

 

TPI/03: The Alps - homogenous source of atmospheric dynamic in climate models? Transnational studies of dynamic of atmopheric waves in the mountains (LUDWIG)

 

The aim of this subproject is to contribute to the improvement of climate, atmospheric and weather models and their forecast by means of analyzing gravity waves in the Alpine region.

Gravity waves are air circulations with horizontally wavelength from a few to several thousand kilometers. Their period duration is between a few minutes to several hours. They can move on long distances in the atmosphere and thereby link the different regions of the atmosphere. Gravity waves are even capable to influence spacious air flows. Often they are formed in high mountain ranges. Due to the low scale, gravity waves are just oversimplified contained in climate and atmosphere models. The goal of this subproject is to figure out if the gravity waves activity in the Alpine region is constant or varies during the year.

 

Climate observation with GRIPS

In this framework a team of experts under the leadership of the German Aerospace Center of the DLR analyzes the activity of gravity waves at different research stations in the Alpine region by means of identical land-related measurement instruments (GRIPS and FAIM instruments). The scientists use airglow that occurs in the height of 80 to 100 km for their measurements. The intensity of this airglow is modulated by gravity waves. With the aid of the measured data, the scientists can determine characteristic parameters of the gravity waves, like amplitude, period duration respectively wave length and energy. Thereby the prerequisite for an improved integration of gravity waves into climate and weather models is created.

Besides gravity waves, also infrasound waves influence airglow. Both types of waves can be produced by natural disasters like storms, tsunamis and earthquakes. Their identification in measurement data of that kind can provide additional information about the appearance respectively the activity of natural catastrophes.

Furthermore the measurement of airglow allows to draw conclusions of the temperature in those high altitudes. Unlike on the ground, carbon dioxide has a cooling effect there, whereas this cooling effect is stronger than the heating at the ground. Long-term measurements at different locations enable to make earlier statements about the carbon dioxide-based greenhouse effect in the future.

Contact TP I / 01
Dr. Ralf Sussmann
KIT IMK-IFU
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Tel. ++49 (0)8821 183 159
Fax ++49 (0)8821 73573

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Contact TP I / 02
Contact TP I / 03
Prof. Dr. Michael Bittner
DLR - DFD
Uni Augsburg-AFE
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Tel. +49 8153 28-1379
Fax +49 8153 28-1363

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Dr. Sabine Wüst
DLR - DFD
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Tel. +49 8153 28-1325
Fax +49 8153 28-1363

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