Thursday, May 10, 2012

Still Active in the North, AR 11476 Flares Up!

The SWPC in Boulder issued a flare alert after an M-class flare in active region 11476. Here is an EVE plot from noon today showing the history of spectral irradiances. We usually look at the blue line in the top panel, the ESP 0.1-7 nm radiometer. It is very similar to the GOES X-ray measurements. The M-class flare is the spike in the blue line just after 0400 UT today. The dark count is a measure of the energetic particles hitting SDO and usually rises around 1800 UT each day because of the Earth's radiation belts.
Space Weather Message Code: ALTXMF
Serial Number: 170
Issue Time: 2012 May 10 0418 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2012 May 10 0417 UTC
NOAA Scale: R2 - Moderate

NOAA Space Weather Scale descriptions can be found at

Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see