Sunday, August 6, 2017

Solar Wind Produces Visible Auroras for the Third Day in a Row

Aurora seen over Great Slave Lake at Yellowknife, Canada on Aug. 5. Credit: Bill Braden.

A high-speed stream of solar wind is blowing around Earth for the third day in a row, producing magnificent auroras in the higher latitudes of both the northern and southern hemisphere. The auroras are visible this week over Canada, northern Siberia, Norway as well as over Antarctica.

Auroras are the result of electrons colliding with the upper reaches of Earth’s atmosphere. When space weather activity increases and more frequent and larger storms and substorms occur, auroras extend equatorward. During large events, these phenomena can be observed as far south as the US, Europe, and Asia. Auroras typically form 80 to 500 kilometers above Earth’s surface.

National Oceanic and Atmospheric Administration (NOAA) informs that solar radiation over the past 24 hours, was below S-scale storm level thresholds. Moreover, no S1 (minor) or greater solar radiation storms are expected. However, a chance for R1 (minor) radio blackouts exists today due to potential flare activity from an active region rotating onto the visible solar disk.

NOAA also revealed that the solar activity is expected to be at low levels this month with a chance for M-class flare (R1-R2/minor-moderate) until Aug. 13 due to the return of the old Active Region (AR) 2665 on the sun rotating across the visible disk. The remainder of the outlook period is expected to be at very low levels.

Geomagnetic field activity is expected to range from quiet to G1 (minor) geomagnetic storm levels over the months. G1 storm levels are expected to occur on Aug. 17-18.

No comments:

Post a Comment