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Thermosphere Climate Index


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49 minutes ago, Newbie said:


There is a metric called Thermosphere Climate Index, it's currently at 16.99. It's the highest value it has been since last solar max.  TCI is a number NASA publishes every day to keep track of the temperature at the top of Earth’s atmosphere–a layer of gas, researchers call “the thermosphere.” At the moment it is considered neutral neither hot nor cold, but is has been steadily increasing. It is a sign that the Sun continues to increase its activity. 

"TCI is based on measurements from the SABER instrument onboard NASA’s TIMED satellite. SABER monitors infrared emissions from carbon dioxide (CO2) and nitric oxide (NO), two substances that play a key role in the energy balance of air 100 to 300 kilometers above our planet’s surface. By measuring the infrared glow of these molecules, SABER can assess the thermal state of gas up there.

Although SABER has been in orbit for only 17 years, Mlynczak and colleagues recently calculated TCI going all the way back to the 1940s. “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,” he explains " T.Phillips Spaceweather.com


Max 49.4 x10^10 W Hot 1957

Min 2.05 x 10^10 W Cold 2009


What was the max value of the last SC?

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8 hours ago, Orneno said:

Very promising, when we’re not expected to hit solar max until 2025 or maybe late 2024 at the earliest!

That may be what you expect, but others think differently. Scott McIntosh et al are suggesting that solar max could be as early as the end of 2023. Both dates are just forecasts. I am not sure where I stand at the moment, but looking at the available data we see that at present the TCI is at a similar value compared to the same time in cycle 24.

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5 hours ago, Drax Spacex said:

Seems to be tracking the 10 yr treasury yield pretty well.

I wonder if the greater number of commercial space vehicle launches in recent years contribute in part to this increase of CO2 and NO in the thermosphere, or if it's just increased solar activity.

In that environment, and at the scale of those particles, it can be assumed a little from column A and a little from column B. The atmosphere is constantly morphing; as particles reach particular elevations, circumstances arise in which those particles "perform functions" they otherwise could not. Subjected to a different blend of weak and strong forces, these particles likely "come and go" in a less traditional sense than the phrase describes; it is likely that subatomic interactions lend that portion of space a proclivity towards changing atomic or molecular identity depending on the factors presented by Earth primarily, near-space environment secondarily, and the Sun tertiarily.

This is not unlike life on Earth itself dealing with arbitrarily-changing circumstances, adapting, and evolving. There is "loss" in a different sense as atoms ionize and effectively translate into other atoms and molecules, as that environment seems to be a "breeding ground" for gasses and water vapor; incoming radiation blows them apart atomically, then radiant Earth-bound energy and baryonic particles join into atomic and molecular structures.

So, we are limited to measuring the atoms and molecules up there. We are not equipped to tap into this process and understand it without being able to discern real quantities of something that is often kept imaginary or arbitrary in calculus. Convenient formulae and explanations have been used in the past to describe various phenomena in the atmosphere, but now that light is being shone, so to speak, on massless particles, and on the confirmed presence of these particles in no scarcity in the Universe, it is pertinent to interject here with the reality of our limitations. It takes particle colliders, and there is no viable way to turn a particle collider into an aeronautical implement... is there? Hmm.

It'd be interesting if we find ourselves in a future, where a mission is being planned to send a super high-tech LEO craft equipped with unfathomably advanced and massive scientific instruments, where it does not necessitate tapping into Earth resources to nearly the same extent as ground-based laboratories. Would humanity object?

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So the thermosphere is basically a high altitude thermal diaper - it heats up and expands during increased solar activity (short term or long term) and perhaps shields the lower altitude layers of the atmosphere from accumulating excess heat? (from convection at least).

SABER seems to be measuing temperature (an intrinsic property) of CO2 and NO which isn't a direct measure of total internal energy (an extrensic property) of the thermosphere.  Not unlike OVATION, I surmise the TCI calculation is using available source data and theoretical mechanizations to extrapolate a prediction of total energy (or power).

I also note the graph for TCI closely matches the graph for Solar Cycle progression - F10.7 cm Radio Flux:  https://www.spaceweatherlive.com/en/solar-activity/solar-cycle.html.  An interesting correlation that has not gone unnoticed, with F30 cm being perhaps an even closer proxy for TCI than F10.7 cm according to this paper:  https://www.swsc-journal.org/articles/swsc/full_html/2017/01/swsc160042/swsc160042.html

TCI provides a curious correlation with solar activity - without needing to look at the Sun at all!

Edited by Drax Spacex
F10.7cm Radio Flux
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  • 7 months later...

I came across this index recently myself; here's what it looks like today:


Interestingly we've already surpassed the peak of SC24 by a comfortable margin, and are now at a comparable level to SC20, which I've seen some indications that this cycle might be similar to. That being said, as stated in the OP the actual measurements only date back 17 years (well, it would be 18 now), while the rest is extrapolated, so I'm not sure exactly how reliable that is; could be that it tracks well enough with the variables that it's viable, I just don't know. At the very least we're clearly past SC24, during which direct measurements were taken.

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Re: SC 20 I was thinking the same thing, but only with regard to the extended 150-170 10.7 flux. Time will tell.   Was also thinking about the downslope, of course.  Sure would be nice to get a repeat performance of Aug 4 1972 with a negative bz this time kids……

Edited by hamateur 1953
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