March 22, 2024

Space Weather: March is Aurora Season, Particularly This Year

We should not forget that the Earth's atmosphere can be seriously influenced by the "weather" on the sun!

Auuoral displays are particularly frequent in March for reasons I will explain later.

The sun's surface is not uniform over time, with varying sunspots and "solar storms", including solar flares and coronal mass ejections (CME), that send solar particles away from the sun and can greatly disturb the sun's magnetic fields.  

Such solar disturbances can be associated with higher-latitude auroras and the disruption of  radio communication and electricity transmission.

CMEs and other solar disturbances are modulated by the number of sunspots on the sun's surface, with more sunspots resulting in more activity.

Sunspots vary over time, with an eleven-year cycle being the most prominent (see below)


Importantly, we are now approaching the peak of a cycle (see a blow-up image below).  So there is an increased probability of solar "action" during this period.


But there is more.    

The potential for auroras and other solar impacts on Earth is maximized in our current season.  As shown in the next figure, the number of days in which solar disturbances impact the earth; 's atmosphere peaks in early spring and early fall, near the time of the equinoxes (night and day being similar lengths)

Why is that?     

It has to do with the orientation of the earth's axis relative to the sun.   During the equinox, the poles are oriented perpendicular to the sun's rays and the magnetic fields of the sun and earth are aligned in an optimal way to produce auroras (I will not go into the details here).


As an aside, you can see the nearly simultaneous sunrise north to south from the visible satellite image this morning (below).   The terminator separating day from night is a vertical line from the north to south poles.


So should you expect any auroral activity soon?   The NOAA Space Weather Center has declared a MINOR geomagnetic storm alert after some minor solar flares a few days ago.  Nothing serious, but it should rev up auoral activity in northern latitudes.   Nothing serious.


But be ready for more interesting solar storms.    The geophysical dice are weighted in their favor this year and season.


6 comments:

  1. Lovely sentiment. Too bad you have to travel out of the PNW to see anything.

    ReplyDelete
  2. I look at the "Aurora Dashboard" daily here https://www.swpc.noaa.gov/communities/aurora-dashboard-experimental . It shows that tomorrow night has a fair chance of seeing an aurora in the Seattle area. Low on the northern horizon, and you should be in a dark place.
    ...if only the cloud cover would cooperate.

    ReplyDelete
  3. Weather on the Sun? Don't tell the progressive politicians and ST reporters. They'll be working even harder to lock us down in order that climate change restrictions can be expanded.

    ReplyDelete
  4. OK .... How soon will the Seattle Times chime in with a claim that climate change makes the probability of damage from solar flare events more likely?

    ReplyDelete
  5. I've only ever seen an aurora in the PNW once, at the peak of the 2000 cycle. Would be nice to catch another without heading up to Alaska

    ReplyDelete
  6. Hello Cliff. Do you have a NOAA contact with Rapid Refresh? The HRRR subhourly hasn't updated since 3/13 and the ensemble status shows 3/9. The hourly run is up to date, but no page announcements about maintenance or end of life.

    ReplyDelete

Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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