Polar stratospheric clouds often are referred to as mother-of-pearl clouds because of their iridescent appearance. But in recent years, the clouds have become the focus of many research projects years due to the discovery of their role in ozone depletion.

These clouds form in altitudes between 20 and 30 kilometers when temperatures drop to -80 degrees Celsius and play a vital role in ozone destruction, but essential aspects of these clouds still remain a mystery, according to the European Space Agency. The agency now is using MIPAS, an instrument onboard the Envisat satellite, to collect data on the clouds to provide scientists with information about these clouds necessary for modeling ozone loss

Using data collected by MIPAS, a German-designed instrument that observes the atmosphere in middle infrared range, scientists discovered a belt of nitric acid trihydrate (NAT) PSCs developing in the polar night over Antarctica in 2003 about a month after the first PSCs, which were composed of water crystals, were detected.

The thinning of the ozone is caused by the presence of man-made pollutants in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons. During the southern hemisphere winter, temperatures drop to very low levels causing the chemicals in the stratosphere, which is in complete darkness during the winter, to freeze and form PSCs that contain chlorine.

As the polar spring arrives, sunlight returns and creates chemical reactions in PSCs responsible for converting benign forms of chlorine into highly ozone-reactive radicals that spur ozone depletion. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.

Although scientific efforts have focused on determining PSC composition and their formation mechanisms, the process causing the ozone depletion is far from understood. In order to gain a better understanding of ozone depletion, scientists continue obtaining data from various sources some of which include satellite-enabled equipment, allowing them to measure the key species involved in the process and attempt to measure ozone depletion.