There’s nothing quite like the disappointment when a promising CME fizzles out, or when clouds obscure the sky during a magnificent aurora display (we feel for you in the Pacific Northwest!) Experienced aurora chasers point out that such fickleness is part of the excitement, and that’s true! The reason that the question “when can I see the aurora?” has such a complicated answer is that a lot of things have to go just right, and often they don’t. But from a scientific perspective, the story doesn’t end there. In this post, we’ll give you the lowdown on why making a report on aurorasaurus.org when you don’t see the aurora (a “negative report”) can be as scientifically valuable as reporting when you do.
Recent Aurorasaurus map showing positive and negative reports during an aurora event
You can help improve models
Aurora prediction tools like the Kp Index and OVATION Prime use measurements or estimates of disturbances in the Earth’s magnetic field, which are in turn caused by events like geomagnetic storms. These disturbances help scientists detect space weather events that can affect Earth’s magnetic field region and atmosphere in ways that can create aurora. The tools are global, and therefore not very precise for specific areas. Seeing enhancements in global indicators gives us some warning that aurora might appear, but they can only make general estimates and can’t tell us specifically where the Lights will be visible.
This is where you come in. By reporting whether or not you can see the aurora, you provide ground-truth data that helps clarify a modeled “view line”: an estimate of how far away the aurora can be seen. For instance, by 2016 Aurorasaurus citizen scientists had reported so many sightings outside of the view line that we updated our model to be more accurate. In both the Northern and Southern hemispheres it turned out that the true extent of visibility was further toward the equator than previously estimated. Positive reports in clusters can change our calculation of the view line (see image). At the same time, negative reports with clear skies in regions in which the model predicted aurora visibility are very useful for improving the models. And since reports are mapped on the Aurorasaurus website, making a negative report can save nearby citizen scientists a wild goose chase.
Data from February 3, 2016, showing a cluster of positive (“yes”) aurora sightings triangulated in blue. The black line indicated where the view line would have been had there been no data reported. The red line shows how the view line adapts to the cluster of positive sightings. Negative (“no”) sightings outside of that zone could help confirm the boundary. See Case, Kingman, and MacDonald, 2016
Your reports clarify cloud cover
Clouds are often an aurora chaser’s nemesis; they occur much lower in the atmosphere and can block our view of the sky. However, aurora models can’t tell how much cloud cover is necessary to obscure aurora. Global models of night-time clouds are limited, and not easily available to include on our map currently. Scientific all-sky cameras provide steady feeds of image data for specific locations, but clouds can get in the way of their line of sight. On the other hand, citizen scientists are creative and can photograph through breaks in the clouds or drive to get around the weather. That said, negative reports help other chasers by providing information about cloud cover during auroral events.
Report by user Becca from Vestland, Norway, on October 31, 2021. While this location was under the auroral oval and places to the south saw aurora, weather blocked the view in Vestland
Report by user Becca from Vestland, Norway, on October 31, 2021. While this location was under the auroral oval and places to the south saw aurora, weather blocked the view in Vestland.
You can help spotlight light pollution
Light pollution prevents many people around the world from observing aurora, even during strong storms. Dark skies are increasingly few and far between, and light pollution often washes out our view of the dim aurora, rendering it invisible to our eyes. When you provide a negative report near a light-polluted area, it can report how light pollution affects night sky access and help other chasers know that that location is light polluted.
Anonymous negative report from Washington State, USA, on October 30, 2021, showing light pollution interfering with a user’s view of the sky
You can learn more about dark sky advocacy and how it relates to aurora chasing in this presentation to the Aurorasaurus Ambassadors by Aubrey Larsen and Jake Powell of the Western Night Skies Council.
Still from the Aurorasaurus Ambassadors presentation on dark skies by Aubrey Larsen and Jake Powell, quoting Daniel Bulletts, who partnered with Aubrey to share traditional knowledge.
Backdated reports help
Sometimes after a disappointment we need a little time to process, and that’s okay! While we encourage real-time reports, you can also make backdated reports to the Aurorasaurus website anytime (note that the site accepts 2 reports per hour and 6 per day as a spam prevention measure.) Importantly, Aurorasaurus can’t gather backdated reports from Twitter–in order to count, they have to be submitted directly to the website.
Scientists analyze data after the fact, and our datasets cleaned for public distribution. Your backdated reports–positive or negative–are still relevant and can help reconstruct previous aurora events and in aggregate help improve models.
Making the best of it
It’s rough when our hopes for aurora don’t pan out, but it’s part of the challenge of chasing the elusive. Negative reports can provide information to help current and future aurora chasers. In addition to letting the folks around you know whether the aurora is visible, you can help improve models, gather info about clouds, and provide important data on light pollution. So regardless of what the weather does, your aurora reports are useful! For example, if you successfully outwit the clouds that’s helpful to scientists, and if you are socked in, it can help nearby chasers. So as we head toward aurora season in the northern hemisphere, if you’ve tried to see aurora please make a report, whether positive or negative! Let’s learn more together.
