A photo from open sources Through analysis of observations of several years and computer simulation, scientists have found an increasing the appearance of luminous (silver) clouds at lower latitudes, than previously. First discovered in 1885, silver blue clouds sometimes soar in the night sky near the poles, radiating arbitrary glow. A phenomenon known as silvery clouds in The 20th century began to be observed in ever lower latitudes – between 40th and 50th parallels, puzzling scientists with the question: if the area the habitat of these clouds has really changed, then information about This is connected with understanding the weather and climate of the whole Earth.
A photo from open sources
NASA’s mission called Aeronomy of Ice in the Mesosphere or AIM (translated as “target”), was launched in 2007 for observation silvery clouds, but so far there have been images clouds only near the poles. Now scientists have collected information from several other past and current missions and applied computer a simulation that systematically shows that quantity these bright shining clouds really increased in the area between 40 and 50 degrees north latitude, in the area that covers the northern third of the USA and the southernmost part of Canada. Study published online in the journal Geophysical exploration: atmosphere (Journal of Geophysical Research: Atmospheres) March 18, 2014 of the year.
“Silvery clouds form at a height of 50 miles above surface – so high that they can reflect solar light toward Earth, said James Russell, lead author of the work, atmosphere and planet researcher from Hampton University, state Virginia – AIM and other studies have shown that for cloud formation requires three factors: very low temperatures, water vapor and meteorite dust. Meteorite dust creates areas for which water vapor clings, while low temperatures do not cause the formation of water ice. ”
To study long-term changes in silver clouds Russell and his colleagues used archival data on water vapor and temperatures as well as a proven computer model to translate this data into cloud information. They are used temperature data from 2002 to 2011 from a NASA mission TIMED (energy and dynamics of the mesosphere, ionosphere and thermosphere) and water vapor data from the Aura mission (Aura) from 2005 to 2011. For data processing model used developed by Mark Herwig, co-author of the work.
This model was tested by comparing its weekend data from observations of the Osiris scientific apparatus on the Swedish satellite One that was launched in 2001, as well as with observations US Department of Defense STPSat-1 mission tool SHIMMER, both during flight, these devices were observed silvery clouds on more low latitudes at different time periods. Output is excellent correlated with actual observations, giving a team of scientists Confidence in the chosen model.
The model showed that the appearance of silvery clouds is indeed increased from 2002 to 2011. These changes correlate with the overall a decrease in temperature at an altitude where in the atmosphere silvery clouds. Temperatures at this height vary by high and lower latitudes, indeed, the coldest place in the atmosphere at this height in summer is above the poles, but temperature changes that have arisen raise questions about changes in the general climate system.
Russell and his team will continue research to determine is there an increase in the incidence of silvery clouds and accompanied by a decrease in temperature over 10 years with a decrease in solar heat and energy that happened naturally way when changing solar activity from a maximum in 2002 to the solar minimum in 2009.
“When the sun is at a minimum of its activity, atmospheric heating decreases and a tendency to cool appears which is to be expected, “said Russell.
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