Hemispheric Power

[David Silver]

What does Hemispheric Power refer to? Why 4pm EST Mon June 29 is it moderate/high?

 

[Archmonoth]

It's the amount of energy in the magnetic field. I have seen it at 125+Gigawatt before (in the red). The energy from solar winds and CMEs, flares etc. is absorbed and channeled around in the field. Interplanetary magnetic field - Wikipedia

 

[David Silver]

Thanks, I’m pretty familiar with the IMF, space weather, and it’s effects. Yes it’s “energy”.  I’m asking specifically what measures the “Hemispheric Power”? Which satellite or station? At what altitude is it measured? What is measured, total electron content? And, the rest of my question about today’s measurement. 

Edited June 20, 2022 by David Silver

[3gMike]

18 minutes ago, David Silver said:

Thanks, I’m pretty familiar with the IMF, space weather, and it’s effects. Yes it’s “energy”.  I’m asking specifically what measures the “Hemispheric Power”? Which satellite or station? At what altitude is it measured? What is measured, total electron content? And, the rest of my question about today’s measurement. 

The Hemispheric Power shown on this website is predicted by the SWPC OVATION Model

A technical description of factors taken into account can be found here https://www.swpc.noaa.gov/sites/default/files/images/u33/SOTIRELIS SWW 2010.pdf

The document does mention imaging is also available from the POLAR UV Imager

[David Silver]

Super interesting, very helpful, thank you.

[Archmonoth]

5 hours ago, David Silver said:

Thanks, I’m pretty familiar with the IMF, space weather, and it’s effects. Yes it’s “energy”.  I’m asking specifically what measures the “Hemispheric Power”? Which satellite or station? At what altitude is it measured? What is measured, total electron content? And, the rest of my question about today’s measurement. 

Why is "energy" in quotes? 

The DSCOVR spacecraft is doing the measurements: In Depth | DSCOVR – NASA Solar System Exploration

The measurements are done from Lagrange point 1, about a million miles away. 

Flux is measured, because the swing of the field reflects the disturbance amount. Total electrons aren't measured from what I can find. 

Today seems pretty normal, the swing can range from orange to green pretty quickly. After your post it was back to green within an hour or so. 

[Newbie]

15 hours ago, David Silver said:

Thanks, I’m pretty familiar with the IMF, space weather, and it’s effects. Yes it’s “energy”.  I’m asking specifically what measures the “Hemispheric Power”? Which satellite or station? At what altitude is it measured? What is measured, total electron content? And, the rest of my question about today’s measurement. 

One common piece of information in reference to Aurorae/s is Hemispheric Power. This information is a good indicator of how much auroral activity can be expected. H.P. is an estimate of how much particle energy deposition takes place into earth’s upper atmosphere. Charged particles in the solar wind, ie. plasma: electrons and ions enter the Earth's atmosphere, collide with Earth's atmospheric molecules, there by slowing down and transferring the kinetic energy into light energy. The total particle energy deposited for each hemisphere is estimated in Gigawatts (GW). The higher the number, the  better the Aurorae/s in terms of active motion and intensity.

NOAA SWPC uses a method listed in the OVATION prime model, as has been mentioned, based on a formula that considers seasonal variations and different types of aurorae/s, particle sensor data from DMSP satellites (there are up to four primary operational DMSP satellites which are in sun-synchronous low-earth polar orbits at ~ 450 nautical miles) and solar wind data from DSCOVR (as has also been mentioned).

Hemisperic Power (HP) values in GW (Gigawatts) as follows:

0 -20 : little to no aurorae/s observable.

20 - 50: need higher latitudes in order to see aurorae/s.

50 - 100: very active (motion) Aurora with intense colors

100+: significant geomagnetic storm

Newbie

Edited June 21, 2022 by Newbie
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