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Upper Atmosphere Contracting Due to Climate Change

Posted: 14 Sep 2021 03:54 AM PDT https://ei7gl.blogspot.com/2021/09/upper-atmosphere-contracting-due-to.html



A recent study by scientists found that that the Mesosphere, the layer of
the atmosphere 50 to 80 kms above the surface of the Earth, is cooling and contracting. This was based on 30 years of observations and is due to
rising human-made greenhouse gas emissions.
Scott Bailey, an atmospheric scientist at Virginia Tech in Blacksburg, and
lead of the study, published in the Journal of Atmospheric and Solar-Terrestrial Physics said... “You need several decades to get a handle on these trends and isolate what’s happening due to greenhouse gas
emissions, solar cycle changes, and other effects. We had to put together
three satellites’ worth of data.”
Together, the satellites provided about 30 years of observations,
indicating that the summer mesosphere over Earth’s poles is cooling about
2.5 degrees Celsius and contracting 150 to 200 metres per decade.
Interesting from a radio point of view, when the mesosphere contracts, the
rest of the upper atmosphere above sinks with it including the ionosphere.
This could potentially lower the height of the Sporadic-E layer which form during the Summer months at about 105 kms which would result in shorter
skip distances. However, if the region is only dropping 200m or 0.2% in
height per decade then it's unlikely anyone will see any real difference in
the short term.
The contracting atmosphere also means less drag on low orbit satellites
which means that more space junk in low-Earth orbit.

The mesosphere is also known for its noctilucent or polar mesospheric
clouds near the polar regions. These clouds form in summer, when the
mesosphere has all three ingredients to produce the clouds: water vapor,
very cold temperatures, and dust from meteors that burn up in this part of
the atmosphere.
These clouds are getting brighter, drifting farther from the poles, and appearing earlier than usual. This area of the mesosphere also reflects
radio waves and may well play a significant role in multi-hop VHF openings across the polar regions.
Link: NASA Satellites See Upper Atmosphere Cooling and Contracting Due to Climate Change

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