Investigations of SOFIE meteoric smoke measurements recently lead to the discovery of a seasonal layer of neutralized H2SO4 aerosol mixed with meteoric smoke. This autumnal layer is located above the nominal stratospheric sulfate (H2SO4) aerosol layer and into the lower mesosphere [Hervig et al., 2017]. Meteoric smoke has traditionally been understood as a passive tracer which follows the global mesospheric circulation. Smoke extinctions from SOFIE, however, show that while this is true in the middle to upper mesosphere (pressure < ~0.2 hPa), it is not true near the stratopause.
in the Mesosphere (AIM) satellite mission is exploring Polar Mesospheric Clouds
(PMCs), also called noctilucent clouds, to find out why they
form and why they are changing.
The AIM mission was launced in 2007 and has been extended by NASA through the end of FY15. During this time the
instruments monitor noctilucent clouds to better understand
their variability and possible connection to climate change.
Individual instrument data collection status, as well as spacecraft
and instrument health, will be monitored throughout the life
of the mission and reported periodically on this website.
The primary goal of the AIM mission is to help scientists understand whether the clouds' ephemeral nature, and their variation over time, is related to Earth's changing climate - and to investigate why they form in the first place. By measuring the thermal, chemical and other properties of the environment in which the mysterious clouds form, the AIM mission will provide researchers with a foundation for the study of long-term variations in the mesosphere and its relationship to global climate change. In addition to measuring environmental conditions, the AIM mission will collect data on cloud abundance, how the clouds are distributed, and the size of particles within them.
Glowing silver-blue clouds that sometimes light up summer night skies at high latitudes, after sunset and before sunrise, are called noctilucent clouds. Also known as night shining clouds, they form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth’s surface. They’re seen during summer in polar regions. They’re typically seen between about 45° and 60° latitude, from May through August in the Northern Hemisphere or November through February in the Southern Hemisphere.
Noctilucent clouds are thought to be made of ice crystals that form on fine dust particles from meteors. They can only form when temperatures are incredibly low and when there’s water available to form ice crystals.
Why do these clouds – which require such cold temperatures – form in the summer?
Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6o to 16o below the horizon. If you see luminous blue-white tendrils spreading across the sky, you've probably spotted a noctilucent cloud. Although noctilucent clouds appear most often at arctic latitudes, they have been sighted in recent years as far south as Colorado, Utah and Virginia. NLCs are seasonal, appearing most often in late spring and summer. In the northern hemisphere, the best time to look would be between mid-May and the end of August.
AIM NASA SCIENCE RELEASES & NEWS
NASA’s AIM Observes Early Noctilucent Ice Clouds Over Antarctica
Date: December 2, 2016 www.nasa.gov
Data from NASA’s Aeronomy of Ice in the Mesosphere, or AIM, spacecraft shows the sky over Antarctica is glowing electric blue due to the start of noctilucent, or night-shining, cloud season in the Southern Hemisphere. This data was collected from Nov. 17-28, 2016.
“The strange behavior of noctilucent clouds over Antarctica in recent months has researchers on the trail of new teleconnections in Earth's atmosphere, which can alter weather and climate on a global scale.”
“Earth's poles are separated by four oceans, six continents and more than 12,000 nautical miles. Turns out, that's not so far apart. New data from NASA's AIM spacecraft have revealed "teleconnections" in Earth's atmosphere that stretch all the way from the North Pole to the South Pole and back again, linking weather and climate more closely than simple geography would suggest.”
“Data from NASA's AIM spacecraft show that noctilucent clouds are like a great "geophysical light bulb." They turn on every year in late spring, reaching almost full intensity over a period of no more than 5 to 10 days. A vast bank of electric-blue clouds has appeared over Antarctica, signaling the start of the season for southern hemisphere noctilucent clouds.”
“Glowing electric-blue at the edge of space, noctilucent clouds have surprised researchers by appearing early this year. The unexpected apparition hints at a change in the "teleconnections" of Earth's atmosphere.”
“Anyone who's ever seen a noctilucent cloud or “NLC” would agree: They look alien. The electric-blue ripples and pale tendrils of NLCs reaching across the night sky resemble something from another world. Researchers say that's not far off. A key ingredient for the mysterious clouds comes from outer space. "We've detected bits of 'meteor smoke' embedded in noctilucent clouds," reports James Russell of Hampton University, principal investigator of NASA's AIM mission to study the phenomenon. "This discovery supports the theory that meteor dust is the nucleating agent around which NLCs form."
Strange Clouds at the Edge of Space
Date: August 25, 2008 View Article Source: NASA
“When in space, keep an eye on the window. You never know what you might see. Last month, astronauts on board the International Space Station (ISS) witnessed a beautiful display of noctilucent or "night-shining" clouds. The station was located about 340 km over western Mongolia on July 22nd when the crew snapped this picture”
FY 2007 Year in Review: The Science Mission Directorate's Input to the President's Space and Aeronautics Report2007
Date: December 2007 View Article Source: NASA
“NASA SMD successfully launched four new space science missions designed to improve our understanding of solar processes, the Earth, and the history of the solar system. Those missions are: …. Aeronomy of Ice in the Mesosphere (AIM), launched on April 25.”
Date: February 19, 2003 View Article Source: NASA
“They hover on the edge of space. Thin, wispy clouds, glowing electric blue. Some scientists think they're seeded by space dust. Others suspect they're a telltale sign of global warming.They're called noctilucent or "night-shining" clouds (NLCs). And whatever causes them, they're lovely. "Over the past few weeks we've been enjoying outstanding views of these clouds above the southern hemisphere," said space station astronaut Don Pettit during a NASA TV broadcast last month. "We routinely see them when we're flying over Australia and the tip of South America."