The sun is going into the deepest Solar Minima of Space Age with research showing the absence of sunspots for most of 2018, while the ultraviolet output of the sun dropped sharply and the upper atmosphere of Earth is responding.
Close to the Edge of Space, the Atmosphere is Losing Heat Energy
Martin Mlynczak of the NASA Langley Research Center said:
“We see a cooling trend. High above Earth’s surface, near the edge of space, our atmosphere is losing heat energy. If current trends continue, it could soon set a Space Age record for cold.”
The SABER instruments which are on-board the NASA TIMED satellite revealed the results after monitoring the infrared emissions from CO2 along with NO, nitric oxide. Both of the substances play a huge role in the energy balance of air which is between 100 to 300 kilometers above the surface of the planet according to spaceweatherarchive.com. SABER makes an assessment of the thermal state of the gas at the top of the atmosphere; this is the layer that researchers have given the name of “the thermosphere”.
There is good and bad to the Solar Minimum
Mlynczak, the associate principal investigator for SABER said:
“The thermosphere always cools off during Solar Minimum. It’s one of the most important ways the solar cycle affects our planet.”
The atmosphere shrinks when it cools, which means the radius of Earth’s atmosphere decreases, which in turn means the aerodynamic drag on the satellites lying in orbit in low-Earth is also decreased, leading to their life being extended. There is both good and bad news to this effect with the bad being that natural decay of junk in space is delayed, leaving the environment around Earth cluttered for longer.
The Thermosphere Climate Index
Mlynczak introduced the “Thermosphere Climate Index” recently so as to be able to track what has been happening in the thermosphere. The TCI is a number shown in watts revealing the heat NO molecules put out into space. When the index is high during Solar Maximum it is hot and when the Solar Minimum is low it is cold. At the moment it is extremely low. Mlynczak went on to say SABER is showing 33 billion Watts of infrared power from NO. He pointed out this was smaller than seen in active phases of the solar cycle by around ten times.
Researchers Used SABER to Calculate the Index Back to the 1940s
The Thermal Climate Index has been calculated back to 1940 despite the fact SABER has only been orbiting for the last 17 years.
Mlynczak said:
“SABER taught us to do this by revealing how TCI depends on other variables such as geomagnetic activity and the sun’s UV output–things that have been measured for decades.”
The Thermosphere Climate Index is not on the point of setting a space-age cold record as 2018 is coming to an end. Mlynczak said, “We’re not there quite yet, but it could happen in a matter of months.”
James Russell, the SABER Principal Investigator at Hampton University, said:
“We are especially pleased that SABER is gathering information so important for tracking the effect of the Sun on our atmosphere. A more than 16-year record of long-term changes in the thermal condition of the atmosphere more than 70 miles above the surface is something we did not expect for an instrument designed to last only 3-years in-orbit.”
Spaceweather. com will be including the Thermosphere Climate Index as regular data feed on the website allowing people to keep up with the state of the upper atmosphere.