Arctic SOLVE mission living up to its name

One of the objectives of the initial research stage are to hunt for these polar stratospheric clouds.

January 27, 2000
Web posted at: 11:59 a.m. EST (1659 GMT)

By Environmental News Network staff

The first phase of NASA's SOLVE mission, launched in November in Kiruna, Sweden, to measure ozone levels and changes in the upper Arctic atmosphere during winter, is proving to be a success. More than 350 researchers, working in bitter cold, are answering crucial questions about the Arctic atmosphere and ozone hole.

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Scientists have observed unusually low levels of ozone over the Arctic in recent winters, raising concerns that ozone depletion there could become as widespread as in the Antarctic region.

The SAGE III Ozone Loss and Validation Experiment, or SOLVE, is based north of the Arctic Circle at "Arena Arctica," a large hangar that houses scientists and aircraft. There researchers are measuring ozone and other atmospheric gases using instruments on the ground and aboard satellites, airplanes and balloons.

The main objectives of the initial research stage are to measure the distribution of ozone before the anticipated depletion and to hunt for polar stratospheric clouds. So far, the Arctic winter has been very cold, creating favorable conditions for polar cloud formation.

Polar stratospheric clouds contribute to a complex process of ozone breakdown, triggering reactions known as heterogeneous chemical processes that accelerate ozone loss. Although the stratosphere is very dry, extremely cold temperatures cause clouds to form.

To help find the clouds, weather forecasters on the SOLVE team determined the location of the polar vortex and tried to pinpoint areas where temperatures would induce cloud formation. The polar vortex is the wintertime weather pattern in which the stratosphere flows counterclockwise around the North Pole.

More than a decade ago, researchers determined that manmade chlorine and bromine compounds were a primary cause of ozone depletion. Chemical reactions occur on the surface of polar stratospheric clouds, producing ozone-depleting forms of chlorine and bromine.

NASA's DC-8 prepares to take off from its base at Arena Arctica.

NASA's DC-8 aircraft arrived in Kiruna on Nov. 29, 1999. When it returned to the United States on Dec. 16, researchers had taken more measurements of polar stratospheric clouds than at any other time.

The aircraft flew to regions where onboard light detection and ranging instruments could probe the clouds. LIDAR, as it is known, is similar to radar but uses lasers that allow researchers to obtain atmospheric data.

In their reconnaissance, researchers discovered that polar stratospheric clouds were nearly always found over high-latitude islands.

Scientists also found colder-than-expected temperatures inside the vortex northeast of Kiruna over Franz Josef Land in Russia. This proved to be a particularly good area for cloud-hunting.

The four science flights over Russian territory were closely coordinated between Russian scientists and members of the SOLVE team. Scientists sampled polar stratospheric clouds extensively as the aircraft flew through an expanding "cool pool" of air in the vortex. The researchers also measured the "mountain waves" that appear to contribute to the cloud formation.

Two NASA-sponsored SOLVE balloons made successful trips into the polar vortex, which had moved overhead by late November. Both balloons measured air estimated to be six years old that had moved from 100,000 feet to 12,000 feet. The air mass contained ozone, chlorofluorocarbons and other gases.

European airplanes will soon join NASA's research fleet, and scientists will launch more balloons from Esrange, a facility near Kiruna.

SOLVE is a joint project of NASA and the European Commission-sponsored Third European Stratospheric Experiment on Ozone 2000. Research teams include scientists from NASA, Europe, Russia, Japan and Canada.

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