How Long is the Delay Between DSCOVR and Earth?

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Great Question, Thanks Spencer,

The Deep Space Climate Observatory, or DSCOVR, is a satellite launched in 2015 carrying several instruments for measuring space weather. It is stationed about 1.5 millions kilometers from Earth at the gravitational balance point between Earth and the Sun known as Lagrange One. The data from this satellite is available on the space weather prediction center’s website, and it is also used to power the NLN DSCOVR Real Time Solar Wind graphics on this site.

Being 1.5 million kilometers away means there is a lag time between when solar events hit DSCOVR and when they arrive at Earth. Clouds of charged particles that travel on the solar wind, such as CMEs and solar storms, typically travel at between 350 and 800 km/s. At those speeds, it takes between 30 and 75 minutes for events measured at DSCOVR to arrive at Earth. When the solar wind is moving faster, like during a coronal hole high speed wind stream or while Coronal Mass Ejection solar storm is passing, the lag time is less. When wind speeds are more ambient, the lag time is longer. Here’s a helpful chart to help see the relationship between wind speed and lag between DSCOVR and Earth:

This table shows the lag between data is measured at DSCOVR and when it registers at Earth
This table shows the lag between data is measured at DSCOVR and when it registers at Earth

There is currently no way of measuring the orientation of the magnetic fields of clouds traveling on the solar wind until they reach DSCOVR. Space weather forecasters are dependent on the measurements taken at the satellite to seed the models that predict aurora. This is why accurate KP predictions can only be made 30-75 minutes in advance. In addition to letting aurora hunters on Earth know what to expect, the data also provides lead time to near earth satellite operators to know if they need to put their satellites in hibernation or protective modes to shield from magnetic fields that could damage sensitive electronics on board.

Fun Fact – DSCOVR also hosts the EPIC (Earth Polychromatic Imaging Camera) instrument, famously championed by Al Gore. This camera beams a true-color image of Earth about once every two hours. You can see the images it is sending back by following the EPIC twitter account. Read about all the specs of the camera on board here.

"Blue Marble" style image of Earth from EPIC camera on October 17,  2016
“Blue Marble” style image of Earth from EPIC camera on October 17, 2016

Happy Hunting

Are the Aurora and Northern Lights Active Now?

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Thanks for this question Parin,

Your best bet for determining if there is currently aurora activity is to take a peak at the current KP value. The chart on that page shows the current KP and the expected KP over the next 30-75 minutes. KP is a global scale that ranges from 0 to 9, the higher the value, the more active the aurora is and the closer to the equator it may be visible.

Once you know the current KP, you will want to know if it is possible to see aurora where you are at that KP. This map helps with that:

Global KP boundaries map shows what KP you need to see Aurora
Global KP boundaries map shows what KP you need to see Aurora[/

[caption id="attachment_1365" align="aligncenter" width="689"]Southern Hemisphere KP Maps Southern Hemisphere KP Maps

Find your location on this map, If you are in the Northern Hemisphere the KP level you need is the line to the south of your location. Likewise, if you are in the southern hemisphere the value you need is on the line to the north of your location.

Finally, check your weather. Aurora displays are high in the atmosphere. If it is cloudy, the aurora will be above the clouds and you will not be able to see them.

Happy Hunting

Update #2: Mid-October Aurora Reached G2 storming, G3 predicted

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Northern Lights Now – The predicted G1, then upgraded to G2, aurora predicted for October 13-15 is meeting and exceeding expectations. KP values recorded in 3-hour increments by the airforce and SWPC were registering between G1 and G2 for much of the day. KP predictions from the Wing-KP model ranged from 4.67 to 7.67 from Noon GMT through Midnight GMT. SWPC has upgraded the watch level on the 14th to G3. Storming will likely only reach that level if the storm continues to intensify – and there have been some hints that it is starting to wane. Here is the chart showing today’s recorded geomagnetic activity:

Global Geomagnetic activity recorded on Oct 13 in 3-hour increments
Global Geomagnetic activity recorded on Oct 13 in 3-hour increments

At the peak of today’s storm the Bz had rotated powerfully to the south, registering as much as -20 nT. This is some of the strongest negative orientation of the Bz since the Saint Patrick’s day storm of 2015. In addition to being strongly south, the field maintained that orientation for a long time. As of this writing, the Bz had been negative for almost 20 hours. This is the longest duration negative Bz since NLN started producing this graphic that shows the duration certain important thresholds for aurora have been exceeded:

NLN Solar Wind Charts show long duration and powerfully south oriented Bz and strong Bt too
NLN Solar Wind Charts show long duration and powerfully south oriented Bz and strong Bt too

With a storm this strong, we’d normally expect to see many wonderful aurora pictures rolling in from our readers and aurora hunters. However, there were a lot of clouds in the normal viewing locations. In NLN’s HQ city of Burlington Vt it was raining most of the day and is cloudy this evening. The Moon is also nearly full, currently at 94% visible, and is washing out the aurora for people who have clear skies. That isn’t stopping photographers, and there are a few beautiful pictures rolling in. Here are a few. Please tag @northlightalert in your photos if you’d like to have them featured in the NLN blog!

Ontario got in on the action:

And upstate New York in Rochester:

Behind a tractor in Wisconsin:

Just a hint from Ireland: