NASA captures 1st view of polar clouds

[Owlscrying]

June 29

A NASA satellite has captured the first occurrence this summer of mysterious iridescent polar clouds that form 50 miles above Earth's surface.

These mystifying clouds are called Polar Mesospheric Clouds, or PMCs, when they are viewed from space and referred to as "night-shining" clouds, or noctilucent clouds, when viewed by observers on Earth. The clouds form during the Northern Hemisphere's summer season that begins in mid-May and extends through the end of August. They are being seen by AIM's instruments more frequently as the season progresses. The clouds also are seen in the high latitudes of the Southern Hemisphere during the summer months

Very little is known about how these clouds form over the poles, why they are being seen more frequently and at lower latitudes than ever before, or why they have been growing brighter. AIM will observe two complete polar mesospheric cloud seasons over both poles, documenting for the first time the entire, complex life cycle of PMCs.

The AIM instruments are returning valuable information on the global extent and variability of these clouds and preliminary information on their particle sizes and shapes. Early indications are that the clouds occur at high latitudes early in the season then move to lower latitudes as time progresses. The AIM science team is studying these new data to understand whether the changes in the clouds may be related to global climate change.

The satellite was launched on April 25, only four weeks before the first science observations began.

The Cloud Imaging and Particle Size instrument offers a 2-D look at the clouds, collecting multiple views from different angles. The cameras are providing panoramic PMC images of the Arctic polar cap daily. The Solar Occultation For Ice Experiment is measuring new information on cloud particles: their variability with altitude, the chemicals within the clouds and the environment in which the clouds form. The Cosmic Dust Experiment is recording the amount of space dust that enters Earth's atmosphere to help scientists assess the role this dust plays in PMC formation

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