The VIIRS day-night band detects nighttime light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, reflected moonlight, and auroras.
In this view, the northern lights appear as a bright white strip across parts of Montana, Wyoming, the Dakotas, Minnesota, Wisconsin, Iowa, and Michigan. But auroras are dynamic, and different coverage and patterns of light would have been visible at other times of the night. And while these satellite data are shown in grayscale, viewers on the ground saw colors from green (the most common) to purple to red. Atmospheric compounds found at different altitudes influence an aurora’s color.
It boggles the mind a bit that by imaging the aurorae from above, with city lights visible and states and lakes outlined, what we kind of have, above, is a map of the aurorae—at least at a single moment in time.
We were warned that this weekend’s solar storm could have an impact on GPS and navigation systems. 404 Media reports that it’s causing outages in the GPS and real-time kinematic (RTK) positioning systems used in many farmers’ tractors, right in the middle of planting. This is a bigger problem than you might think: quite a lot of crops are grown using precision agriculture, “with farmers using increasingly automated tractors to plant crops in perfectly straight lines with uniform spacing. […] If the planting or harvesting is even slightly off, the tractors or harvesters could damage crops or plant crooked or inconsistently, which can cause problems during the growing season and ultimately reduce yield.” To say nothing of the harvest. Precision agriculture achieves centimetre-level accuracy, but also relies on it, and losing it at one step of the process can’t be good. [Engadget, The Verge]
It turns out that auroras are a thing you can generate weather maps for. NOAA’s Space Weather Prediction Center has this experimental Aurora Dashboard that predicts the visibility of the aurora borealis and australis for the next two nights.
(And space weather is in fact something that NOAA tracks: the term covers the effects of solar phenomena, cosmic rays, the ionosphere—think aurora sunspots, solar flares, coronal mass ejections, and their impacts on climate, communications, the power grid, GPS.)