To the Arctic and Back Again: Research from Aerospace

Icy frost, massive pack ice and powerful cyclones between polar night and all-day light: The Arctic makes it hard for science to unlock its secrets. For over 25 years now, the Alfred Wegener Institute for Polar and Marine Research (AWI) in Bremerhaven explores the Arctic and Antarctic also from out of the air. In the past year, the German polar aeroplane POLAR 5 departed for a very special Arctic measurement flight. POLAR 5, a modified DC-3, is the latest aeroplane of the polar flying squadron. It took up operations only two-and-a-half years ago. POLAR 5 can fly longer distances and at the same time carry more weight than its predecessors, so that now much more encompassing areas can be explored than was hitherto possible. Furthermore, POLAR 5 features numerous in-situ and remote measuring systems, which can be employed in parallel and for different purposes.

Within the context of the PAM-ARCMIP Campaign (Pan-Arctic Measurements and Arctic Climate Model Simulations), the high flyer took off from Spitsbergen for Alaska in April 2009 and covered a wide, hitherto inaccessible and hence unexplored area. It landed on only two metre thin ice on an ice float at the Russian drift station NP-36. This additional refuelling stop enabled a flight as far as 88° 40´ North, a northern record for POLAR 5. “The mere preparation logistics of the trans-Arctic tour were a major challenge. Without international cooperation, this encompassing project never would have been realisable”, says Dr. Andreas Herber. The AWI physicist headed the project.

During the measuring flight, 20 scientists and 6 engineers from Germany, Italy, Canada and the USA collected data on aerosols, trace gases, the thickness of marine ice as well as weather data. Aerosols are floating particles such as dust, sand, emissions from traffic or industry, but also large organic molecules emitted by forests. Like water droplets and ice crystals, aerosols have an effect on the climate and so far figure amongst the greatest uncertainty factors in estimating future climate changes.

Sensors register how much the aerosols cloud the atmosphere. “We have found a high degree of aerosol pollution over the entire Arctic with the highest values above Barrow, the northern-most community in Alaska.” Yet where does the Arctic haze come from? According to analysis of the POLAR 5 data, most of it seems to come from the Asian part of Russia, from Northern America and Europe. Weather conditions in early 2009 brought large clouds to the North Pole region and the volcanic eruption of Mount Redoubt one month prior to measurements increased the whole affair.

Furthermore, the campaign rendered for the first time ever also large-scale data regarding the distribution of marine ice in the Arctic. Whereas such measurements usually require an ice thickness probe attached underneath a helicopter,this could be employed for the first time from an aeroplane and this meant that a much larger area could be covered. POLAR 5 lowered the probe on a wire rope and pulled it across the ice surface in twenty metres height. “When combining these data with satellite measurementsand model calculations, we obtain another important element in predicting what will happen to the Arctic ice.” The flight revealed ice thickness ranging between 2.5 metres in two-year-old ice in the vicinity to the Pole and 4 metres in several-year-old ice at the Canadian coast. On the whole, the ice was thicker here than in previous years, perhaps it has recovered – temporarily. “The major trend of receding marine ice continues”, Herber is convinced.

Yet in order to be able to make reliable predictions as regards its future, further detailed measurements from the entire Arctic are required. And hence Herber and his colleagues will take off with POLAR 5 again in the spring of 2011: This time, they start from the opposite direction in Alaska, along the Canadian and Greenland coast to Spitsbergen with a detour to the inner Arctic in order to augment and refine the 2009 image.