Season’s First Shining Clouds Caught over Northern Hemisphere
03.07.2007 - Logistics, Other
A National Aeronautics and Space Administration's (NASA) satellite, the Aeronomy of Ice in the Mesosphere (AIM), has observed this season's first iridescent polar clouds. They were first detected at 70 degrees north on May 25 by the AIM satellite and then on June 6 by Earth observers in northern Europe.
These mysterious clouds are called Polar Mesospheric Clouds, PMCs, when they are viewed from space and noctilucent clouds when they are caught by observers on Earth. They form at 50 miles above the Earth's surface during the respective summer season of each hemisphere: from mid-May through end of August for the northern hemisphere and from late-November through mid-March in the southern hemisphere.
Within the International Polar Year's scientific program, AIM constitutes the ninth Small Explorers mission under the NASA's Explorer Program. Early results from the AIM mission will be reported in Fairbanks, Alaska, in late August 2007 during a press conference on PMCs and other high altitude layered phenomena.
Very little is known about how these clouds form over the poles, why they are occurring more frequently than before and at lower latitudes, and why they are brighter. The AIM will gather information over two complete polar mesospheric cloud seasons in the two poles. It will be studied whether the changes in the clouds can be related to global climate change.
