The Antarctic vortex lasts longer and gets colder than the Arctic vortex. These conditions support the chemistry that leads to massive ozone depletion in the Antarctic region. Record low ozone values over an expanded ozone hole were observed over Antarctica last September and October. Ozone is also declining at mid-latitudes. Mid-latitude ozone losses in the Northern Hemisphere are 6 percent to 10 percent per decade from January to March.
Losses are even larger in the Southern Hemisphere during the winter and spring.
In the Northern Hemisphere, atmospheric motion patterns caused by land masses and mountainous terrain break up the Arctic polar vortex before a massive loss occurs. The proposed fleet of supersonic aircraft would operate in the lower stratosphere, primarily in the northern mid-latitudes. The projected large amounts of aircraft exhaust could alter the stratospheric chemical balance, affecting ozone. It also will study the chemical transformations, especially those affecting ozone. The enhanced payload on the ER-2 aircraft will provide important new information on the chemistry, dynamics and ultraviolet sunlight in the stratosphere.