On an ice floe to the North Pole
Drift station NP-35 on a long trip through the Arctic OceanRead out
At the end of August, an unusual Russian-led expedition will launch into the Arctic Ocean. For eight months, the NP-35 drifting station will go on a long trip to the North Pole - without ship propulsion and without a route. The researchers on board want to investigate, among other things, the sea ice and ice-related measurements. The aim is to complement the previously incomplete data in the Arctic and to better understand the key region of global climate change.
Jürgen Graeser from the Alfred Wegener Institute for Polar and Marine Research is part of the Helmholtz Association. For the first time in the history of Russian research of drift stations since 1937/1938, a German participates in the North Pole drift station NP-35. It complements the work of the Russian project partners with measurements in the atmosphere.
Experience with regular Russian drift stations in pack ice dates back to 1952, when the NP-2 research station was launched. While previous drift stations were exclusively for Russian research, an international station is planned for the first time during the International Polar Year. The project is being carried out in collaboration with the Arctic and Antarctic Research Institute (AARI) in Saint Petersburg.
A total of 36 expedition participants will be on board the Russian research vessel "Akademik Fedorov" on August 29, 2007 in Tiksi, Siberia. In the area of the Wrangel Island between 80 to 85 ° north latitude and 170 ° east longitude to 170 ° west longitude a stable ice floe is chosen as basis for the drift station "North Pole 35" (NP-35). The selection is based on the long-term observation of the ice by satellite and is checked by helicopter from aboard the research vessel.
During the winter, the ice floe in the Arctic Ocean will drift across the North Pole. During the drift, various measurements are taken at the station to give information about the current climate change. The planned evacuation takes place after about a year with the "Akademik Fedorov". For wintering, it is planned to fly Graeser and five Russian colleagues after about eight months in April 2008 with the research aircraft "Polar 5" of the Alfred Wegener Institute. For this purpose, a runway will be created on the ice floe. display
The research programArctic sea ice. Christof L pkes / Alfred Wegener Institute
The Russian colleagues examine the area of the upper ocean layer, the sea ice and the snow cover. Atmospheric measurements of meteorological parameters such as temperature, wind, humidity and air pressure are supplemented by measurements of trace gases such as carbon dioxide and ozone. Gr ser will deal with two topics. On the one hand, he uses the captive balloon system to measure meteorological parameters in the so-called planetary boundary layer, which is the lowest layer of the atmosphere up to a height of about 1, 500 meters. He will also carry out ozone soundings to measure the ozone layer in the stratosphere up to a distance of approximately 30 kilometers.
Key region of global climate change
The Arctic is a key region of global climate change. Measurements of sea ice and atmospheric quantities in the Arctic Ocean are still patchy. With this project, the researchers want to identify atmospheric key processes and the changes in the sea ice cover and to investigate the coupling of sea ice and the atmosphere. The project is one of many within the International Polar Year. More than 50, 000 scientists from more than 60 countries are joining forces to explore the polar regions. Their goal is to investigate the role of the Arctic and Antarctic in the climate and ecosystems of the Earth.
Project "Planetary boundary layer"
Planetary boundary layer English: planetary boundary layer (PBL) - is the lowest layer of the atmosphere from the ground to about 1, 500 meters altitude. In the Arctic, this boundary layer is characterized by a high incidence of temperature inversions, that is to say by a very stable atmospheric stratification, which suppresses vertical movements of the air. A realistic representation of the planetary boundary layer is of fundamental importance in climate models, as the lower boundary conditions are defined for all calculations. In particular, when investigating processes that are affected by the boundary layer itself, it is important to know the state of the PBL accurately.
With the regional climate model HIRHAM, AWI scientists in Potsdam create pressure, temperature and wind fields in which cyclones (low-pressure areas) and their train path are identified. They specifically investigate the relationship between cyclone development and different surface conditions for example sea ice cover. The connection of the Arctic planetary boundary layer with cyclones and their trajectories is the aim of the investigations.
Project "Ozone Layer"
The discovery of the Antarctic ozone hole in 1985 triggered intensive research into the polar ozone layer. This layer is about 15 to 25 kilometers high in the stratosphere. Since then, many chemical processes of ozone depletion in the Antarctic have been clarified and the correlation of ozone destruction with anthropogenic emissions of chlorofluorocarbons (CFCs) and halons has been unambiguously demonstrated.
Also, over the Arctic, which is much closer to us, heavy ozone losses occur during certain winters, which have already contributed to a decrease in the ozone layer thickness across Europe - a development that leads to an increase in harmful ultraviolet radiation on the soil. So far, however, the ozone loss in the Arctic is not as pronounced as over the Antarctic. The thickness of the Arctic ozone layer is much more variable compared to the Antarctic. The known chemical mechanisms explain only about half of the observed variability from year to year. Partly misunderstood dynamic processes are therefore as important for the thickness of the ozone layer over the Arctic as the chemical degradation of ozone.
White spot is eradicated
At the Arctic Station of the Alfred Wegener Institute in Ny Ålesund on Spitsbergen (79 ° N), for example, at high altitudes between 25 and 30 kilometers, a strong annual variation of about 30 percent was found. It seems to be in common with the variability of the sun, but can not be explained by known chemistry or by well-known dynamic processes. The investigation of the cause of this variability is at the center of the ozone measurements on NP-35.
For the first time, the measurements of the drift station will yield high-resolution vertical profiles of the ozone distribution in the central Arctic north of 82 degrees latitude - so far a blank spot in the map of the global ozone distribution. This unique data will be combined with existing records of ozone profiles from the Arctic and sub-Arctic. Calculations of air movements and chemical models will help explain the seasonal and annual variability of stratospheric ozone in the Arctic.
(idw - Alfred Wegener Institute for Polar and Marine Research, 19.07.2007 - DLO)