Thursday, September 08, 2005

Space Weather

Last month's sunspot eruption produced aurora borealis sightings as far south as Utah and Colorado. Yesterday, the sun produced an eruption in the X17 class, one of the largest recorded. So if all your HF receivers went out yesterday and you couldn't even get Radio Nederlands on your short wave set, now you know why.

From the "Official Space Weather Advisory" issued by NOAA Space Environment Center Boulder, Colorado, USA:

2005 September 07 at 01:31 p.m. MDT (2005 September 07 1931 UTC)

One of the largest solar flares on record occurred today, September 07. Very active Region 808 produced a powerful X17 flare (R4 on the NOAA Scale) observed on the NOAA GOES satellite at 07/1740 UTC (September 07, 1:40 p.m. EDT). This flare, the 4th largest in the last 15 years, erupted just as the Region 808 sunspot cluster was rotating onto the visible disk of the sun. Intense radio emissions were also associated with this flare. A very bright and fast coronal mass ejection was observed on coronagraph imagery; however, the material was not Earth directed. An S1 - S2 radiation storm is expected following this eruption, but is not expected to begin until late on September 07 or early September 08.

This event created a complete blackout of high frequency communications on the daylit side of Earth. Communications used by emergency services along the Gulf Coast may have experienced problems due to this flare. Low frequency navigation systems may also have experienced a period of significant degradation.

Over the past two weeks, this active region produced a series of significant solar eruptions as it made its passage around the back side of the Sun. Significant eruptions are expected in the coming days. Agencies impacted by space weather storms may experience disruptions over the next two weeks. These include spacecraft operations, electric power systems, HF communications, and low-frequency navigations

Data used to provide space weather services are contributed by NOAA, USAF, NASA, NSF, USGS, the International Space Environment Services and other observatories, universities, and institutions. More information is available at SEC's Web site

I can't imagine an aurora sighting this far south here in the jewel of southern California but that is an amazingly large sunspot.