Upper Atmospheric Science Research

Space Physics Research Lab

Taking the measure of ozone depletion

Problem:

To make appropriate decisions about global warming, policy makers need accurate, quantitative information about the extent and effects of ozone depletion.

Solution:

Embry-Riddle researchers are conducting observations of the atmosphere that may provide a more accurate measure of temperature changes in the upper atmosphere resulting from the effects of human activities in the lower atmosphere.

Their research is funded by the NASA and the National Science Foundation.

One of the adverse effects of human activities is the depletion of ozone in the polar region. In the Arctic region, this effect is thought to result from processes that take place in the polar vortex, a huge whirlpool of air that circulates 20-50 kilometers above the Arctic surface during the winter.

During the dark polar winter, polar stratospheric clouds, congealed from water vapor and trace acids from man-made chemicals, grow within the polar vortex. A large number of tiny droplets and crystals then grow in the clouds, their surfaces lined with man-made chlorine.

In early spring, sunlight frees the chlorine from the droplets and crystals, and the released chlorine attacks the ambient ozone, contributing to ozone depletion in the Arctic.

Because every degree of warming in the air near the Earth's surface may be 10 degrees greater in the upper atmosphere, measuring temperature in the upper atmosphere allows researchers to calculate the extent of global warming in the lower atmosphere.

"One of the main goals of our Arctic research is to gain a quantitative understanding of the onset, propagation, and filtering of the gravity waves in the Arctic atmosphere during these warming events," Dr. Sivjee says. "We are doing this through electro-optical remote sensing of the effects of these stratospheric warming events at all heights in the Arctic atmosphere, coupled with extensive numerical model calculations."

The breakdown of the polar vortex appears to generate extensive wavelike disturbances. The researchers have observed the effects of these disturbances in the Arctic mesosphere lower thermosphere (MLT) region extending from Eureka Bay and Resolute Bay in the Canadian Arctic to Sondrestromfjord in Greenland and in Longyearbyen, Spitsbergen, north of Norway.

These disturbances generate gravity waves that appear to be associated with cooling in the region 80-120 kilometers above the Earth's surface. Such a high-altitude cooling precedes every stratospheric warming event and may be a forewarning of impending stratospheric warming associated with polar vortex collapse and polar ozone depletion.

Others taking part in the Embry-Riddle project are Irfan Azeem, assistant professor of engineering physics; Bereket Berhane and Anthony Reynolds, assistant professors of physics; and Deli Shen, senior research associate.

Dr. Sivjee's research group is made up of three faculty members, three research associates, three graduate students, and 30 undergraduate students. The research group is also conducting remote-sensing measurements of the effects of solar disturbances on satellite orbits, satellite communication, and other space activity.

Ongoing atmospheric research

Dr. Sivjee has directed the Space Physics Research Lab (SPRL) at Embry-Riddle since 1986. SPRL pursues electro-optical remote sensing of atomic, molecular and plasma processes in the near-earth space environment. The lab operates state-of-the-art scientific instruments all around the planet, focusing on the polar regions for the study of solar-terrestrial interactions, some of which result in auroral displays.

Atmospheric data collection locations include Eureka (Northwest Territories of Canada), Resolute Bay (Northwest Territories of Canada), Sondrestomfjord (Greenland), Longyearbyen (Svalvard, Norway), the South Pole, San Antonio (Texas), Palmas (Brazil), Adelaide (Australia), as well as Daytona Beach. The instruments include Michelson interferometers, CCD spectrometers, filter-wheel photometers, Ebert-Fastie spectro-photometers, and a recently obtained Fabry-Perot interferometer.