It’s Quiet… Too Quiet.

Do you know what makes running a space weather blog easier? Space weather. Like, space weather actually happening.

Guess what’s not happening?  Space weather.  

That is, of course, and exaggeration.  Just like weather on the Earth, space weather is always happening.  Just like on Earth, however, when things are calm and boring, you are less likely to get cool news stories.  

This has been exactly the case with space weather.  The only events that we have observed in the past month or so are from coronal holes.  These are regions on the sun where the solar wind is faster than other places.  The fast solar wind catches up to the slow solar wind on the way to the Earth and compresses up against it.  This is similar to when you’re driving to work, and the slow guy in the fast lane causes ten cars to impatiently bunch up together.  When this bunched-up solar wind arrives at Earth, it creates a small space weather storm.  These types of events are boring and very easy to predict: given a slowly changing Sun, a single coronal hole (the source of fast solar wind) will create a space weather storm every 27 days, which is the time it takes for the Sun to rotate once.

To make things more interesting, we need solar active regions, or sunspots, to spice things up.  Sun spots are small regions on the Sun’s surface where the Sun’s magnetic field and particles are active and unstable.  They are the source of real space weather storms. 

The major problem for interesting space weather is that there are no sunspots.  None!

Images from the Solar Dynamic Observatory showing that Sun spots are on spring break.

This story from NASA has all the details, but the gist of it is that we are currently in a stretch of such weak solar activity that there are no observable sunspots.  The Sun has an activity cycle of 11 years.  We are right in the middle of solar minimum of Cycle 24, one of the most boring solar cycles in recorded history.  The cycle has hit an activity level of zero.  This is so boring that it wraps over and becomes interesting again.

Periods like this are sparse but not unheard of.  There have been long stretches of boring, notably, the Maunder Minimum of the late 1600s and early 1700s.  To be clear, we are not anywhere near that level of inactivity.  Indeed, if you wander over to the Solar Dynamics Observatory data site, you can see that sunspots have already returned.  However, the increasing amount of boring has led some scientists to wonder if we’re not heading into a new prolonged period of solar boring.  This would be especially exciting for solar physicists, who work to understand the solar dynamo.  For space weather, however, it would just be… boring.

See you on the dark side of the Sun.

This is pretty cool- CLaSP professor Justin Kasper is going to be featured in an upcoming Discovery Channel documentary called “The Dark Side of the Sun“.  The program will discuss space weather effects and how we learn about the Sun.  It will include extensive discussion on an upcoming mission, Solar Probe Plus, which will get closer to the sun than any previous mission.  It’s always exciting to see CLaSP researchers in the limelight for their work!

GPS as a Space Weather Monitor

GPS satellite orbits around the Earth.  Each satellite has a radiation sensor that can be used to learn more about the radiation belts.
GPS satellite orbits around the Earth. Each satellite has a radiation sensor that can be used to learn more about the radiation belts.

Big space weather news this week: measurements of the “radiation belts” made by the Global Positioning System satellites are now available to space weather researchers.  This is a huge deal for several reasons, but let’s start by unpacking that sentence:

Continue reading “GPS as a Space Weather Monitor”

New Breakthroughs in Space Weather Prediction at Michigan

A simulated (left) vs. observed (right) CME as seen from near-Earth.  CLaSP's EEGL model is successfully reproducing key features of observations.
A simulated (left) vs. observed (right) CME as seen from near-Earth. CLaSP’s EEGL model is successfully reproducing key features of observations.

One of the ongoing research projects here at the University of Michigan’s Climate and Space department is computer simulations of eruptive events from the solar atmosphere into the solar system.  “Eruptive events” are explosions of material (mostly super-hot hydrogen gas) and magnetic fields into space.  The atmosphere of the sun is locked in a delicate balance between gravity, which holds the atmosphere down, and the expansive force of the super-hot atmosphere, which pushes it away.  On top of this are complicated magnetic and electric forces.  When the balance breaks down, you get an explosion of material into space.  These are known as “coronal mass ejections”, or CMEs.  Simulating these events is incredibly difficult because the physics behind CMEs is only tenuously understood.

Here at CLaSP, scientists have had a breakthrough with their new EEGGL model- the Eruptive Event Generator: Gibson-Lowe model.  This model has had great success in reproducing solar storm observations, which is the first step towards prediction of these storms before they arrive at Earth.  NASA has recently highlighted this new science, so be sure to give that article a read.  

Space Weather at AGU’s Fall Meeting

Ooooh!  Pretty.
San Francisco’s beautiful commercial district skyline, as viewed from Union Square at night in December.

There are a few reasons for the recent dearth of posts here, but prominently,

  1. The weather in space has been especially boring as of recent,
  2. The end of each year is marked by the American Geophysical Union’s Fall meeting.

The latter, known colloquially as “the AGU meeting” by frequent attendees, is an annual gathering of more than 20,000 scientists, spanning many specialties, at San Francisco’s Moscone Center.  At this meeting, there are thousands of presentations, talks, discussions, and meetings.  It occurs every December and has a penchant for consuming participants- both during and well before the event itself.  This is because it requires a great amount preparation before and endurance throughout: you will run from session to session, talk to talk, poster to poster, meeting to meeting, from very early to very late.  It is an extremely important week where your colleagues, competitors, funders, and managers will all be present, so you must be “on” at all times.

This year’s AGU meeting saw a huge increase in sessions dedicated to space weather, with some very exciting talks and discussions.   Continue reading “Space Weather at AGU’s Fall Meeting”

Another Storm Watch!

Here we go again! NOAA SWPC has issued another storm watch for a G3 level geomagnetic event.  Right now, we’re already at G2 level.  My guess is that we’ll hit G3 if the interplanetary magnetic field turns southward, so keep an eye on the real-time solar wind conditions.  Because the storm has already started, I doubt that this will drive any visible aurora over the United States- by the time nightfall hits, the storm will have subsided again.  But keep your eyes peeled just in case.

Check out my previous storm watch post for an idea of what values to watch as the storm progresses.

Storm Post Mortem – Oct. 13, 2016 Event

Happy Monday.  Let’s take a look at the storm that started Thursday and had potential to reach a G3 level on NOAA’s geoactivity scale.  Click for a larger version:

NOAA SWPC real time solar wind values (top four frames) and observed and predicted Kp and Dst indices (bottom two frames, respectively.)
NOAA SWPC real time solar wind values (top four frames) and observed and predicted Kp and Dst indices (bottom two frames, respectively.)

The outstanding feature in the solar wind during this storm is the long period (near 18 hours!) of southward Interplanetary Magnetic Field (IMF).  This is seen in the red line in the top frame starting shortly after Oct. 13th and lasting into the next day.  Southward IMF conditions are when the solar wind most efficiently transfers energy to the magnetosphere and Earth’s atmosphere, so the storm looks promising on these terms alone.  IMF BZ (the component of the field that is oriented north- and southward, shown in the red line in the plot) reaches a value of almost -30nT!  Values of -10nT are good enough to give us a strong response on the ground; -30nT is approaching what we would expect during a very strong storm.

Now, let’s jump down to the bottom two frames, which show the geomagnetic activity indices KP and DST.  The former is an index of the global space weather activity at Earth and ranges from 1 to 9.  The latter is an index of how much energy is stored in the “ring current” of the magnetosphere, a region that extends out to around 8 Earth radii (around 28,000 miles altitude.)  The more negative DST, the more energy stored.  In my previous post, we had hoped that this storm would intensify from “G2” to “G3” status, or a KP of 7 from 5 or 6; DST had already reached -100nT as I frantically typed.  Unfortunately, my post came during the maximum of activity: both DST and KP recovered after that point.  These are moderate values; this is a typical and relatively uninspiring event.  Browsing the community-driven aurora monitoring website, Aurorasaurus, there is evidence of a light show reaching the northern United States, but not much further south than that.

So what happened?  This is a time where the southward IMF values needed a little more help from the solar wind.  The solar wind was relatively slow for a space weather storm (yellow line), staying around 400-500 km/s.  During strong events, we expect much faster values- 600, 800, or even 1000 km/s.  Next, we want a dense solar wind- tens of particles per cubic centimeter.  When the IMF was southward, the solar wind was the least dense: <10 per cubic centimeter.  The IMF was just right, but it didn’t get the help it needed to make this a very exciting space weather storm.

Finally, in the bottom frame, we see a strange discontinuity in the predicted DST as it jumps from -125nT back to zero.  We see a similar jump in the KP plot.  What could’ve happened here?  This is a cold restart of the Space Weather Modeling Framework- something went wrong, and the code needed to be restarted from scratch.  The problem could have happened anywhere in the predictive chain: in the processing of real-time solar wind data, a hardware glitch in the supercomputing environment, or an issue with the SWMF software itself.  This is disappointing, but not completely unexpected- the real-time simulations at SWPC are brand new, and we – the researchers and code developers at the University of Michigan as well as the team at NOAA – will use this event to make the entire system more robust for future storms.

As a scientist, this storm will still be important.  Every storm gives us an opportunity to make new observations of the sun-Earth system.  With our sparse and ever-changing fleet of satellites taking measurements, each storm has the potential for something new to be discovered, even if it is not a record-setting event.  This storm is one of the few that has happened in the lifetime of the young Magnetosphere Multi-Scale (MMS) satellite mission, so I expect some exciting observations to come from that.

Space Weather Alert!

After a series of rather small and, quite frankly, boring space weather events over the past month, it looks like we have something interesting going on!  We are in the middle of a decently-sized space weather storm, and NOAA’s Space Weather Prediction Center (SWPC) warns that it could get stronger tomorrow- reaching a “G3” level on their scale that ranges from G1 to G5.

A large solar event called a coronal mass ejection, or simply a CME, reached the ACE spacecraft around 21:00 UTC (or  around 5pm EDT) on October 12.  (ACE is situated just upstream of the Earth and is first chance for us to directly measure the solar wind before it hits Earth.)  You can see the observations from ACE yourself at SWPC’s website.  Typically, we look for strong, sudden jumps in solar wind speed and magnetic field intensity to find the arrival of a CME.  However, the ACE real-time data is quite spotty right now, so full identification is difficult.  The jump in these values is not very strong, but it’s there.

When we want to tell if a transient event, like a CME, will be geoeffective (that is, will cause a space weather storm at Earth), we want to look at the Interplanetary Magnetic Field (IMF).  The most important factor is the direction of the solar wind: when it’s southward, energy transfer from the solar wind to the Earth is the most efficient.  In ACE observations, this is seen in the Z-component of the IMF.  When IMF BZ is negative, we should expect a strong storm.  IMF BZ has been strongly southward for the past 12 hours, which is surprising!  I would expect this to be a pretty strong storm.

When a storm is underway, there are several geomagnetic indices that tell us about the current conditions.  These are values obtained from ground-based observations of perturbations in the Earth’s magnetic field, then processed into single numbers to help summarize what’s happening.  Let’s look at these:

  • First, there’s KP, which indicates activity on a scale from 1-9.  NOAA considers anything 5 or above to be a storm, and we’re currently sitting at 6.  Things get really exciting at 8 or 9, but 6 is not a storm to scoff at!
  • Next, there’s DST, (bottom plot, in red) which stands for Disturbance Storm Time.  DST attempts to indicate the amount of energy stored in the inner magnetosphere region, measured in nano-Tesla or nT.  A value of zero is observed during quiet times; a more negative number indicates stronger storm conditions.  The strongest storm in the past two decades reached a DST of -500nT.  We’re sitting at -100nT, which is a moderate storm.

With the prediction that things will intensify, keep your eyes on this event, especially if you’re watching for aurora!

This storm is especially exciting because it is the first storm that is being monitored by the Michigan Space Weather Modeling Framework running operationally at SWPC.  You can see the SWMF predicted indices and maps of regional activity over at the SWPC website.