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The ARRL Image Communications Handbook -- Use Amateur Radio to see and talk with other hams! Enjoy the imaging modes: NBTV, ATV, SSTV and WEFAX.
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Solar Wind, Proton Storm Assaulting Earth
NEWINGTON, CT, Jan 17, 2005--This may be the week to check the sky for a display of northern lights and to check the radio for auroral propagation on VHF. A long-duration X-class solar flare earlier today (UTC) from giant sunspot 720 is expected to generate a major geomagnetic storm when it arrives January 18 or 19 (UTC). Spaceweather.com has issued an aurora alert. X-class flares are major events that can trigger worldwide radio blackouts and long-lasting radiation storms. A space weather alert from the National Oceanic and Atmospheric Administration (NOAA) Space Environment Center (SEC) warns that a geomagnetic K index of 6 is expected through today UTC. A watch for a geomagnetic A index of 100 also remains in effect through January 17 UTC. NOAA says active sunspot region 720 has produced several strong solar events.
"Short-wave radio communications through the sunlit hemisphere of Earth experienced significant signal degradation during these solar flares," said a NOAA Space Weather Advisory issued at 1937 UTC today. "Associated strong geomagnetic and radiation storms are under way." NOAA says five large solar flares (CMEs) have produced moderate to strong radio blackouts since Saturday. The largest was measured at X3.8 at 0659 today.
The Solar Terrestrial Activity Report said NASA's Advanced Composition Explorer (ACE) observed a strong increase in proton levels. "Currently, all solar wind measurements are invalid due to the proton storm," the report continued. "Severe geomagnetic storming has been observed since just before noon." NASA says solar wind speeds resulting from the huge coronal mass ejection (CME) or ejections earlier today have compromised the ability of the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) to measure them.
The geomagnetic field is expected to generate active to severe storm conditions for the remainder of January 17 with unsettled to major storm conditions on January 18, due to the CME's effects.
Calling active region 720 "a large and complex sunspot cluster," NOAA predicted further major eruptions are possible from this region before it rotates out of view on January 22.
"Agencies impacted by solar flare radio blackouts, geomagnetic storms and solar radiation storms should continue to closely monitor the space environment through the remainder of this week," the NOAA's bulletin advised.
Page last modified: 05:14 PM, 17 Jan 2005 ET
Page author: awextra@arrl.org
Copyright © 2005, American Radio Relay League, Inc. All Rights Reserved.
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