SOLAR WEATHER




Solar Cycle Progession

Geomagnetic Activity -- The Kp Index and the NOAA POES Auroral Activity Level
In order to know whether you have a chance of seeing an aurora, you need to know the level of geomagnetic activity at the time you are viewing. There is a simple index called Kp, a number from 0 to 9, which is used to refer to geomagnetic activity for a 3-hour period. If the GEOPHYSICAL ACTIVITY FORECAST is for "storm" levels SEC expects Kp indices of 5 or greater. Another indication of geomagnetic activity is the NOAA POES Auroral Activity Level, which is a number from 1 to 10.

Current Estimated Planetary K-index

K-indices of 5 or greater indicate storm-level geomagnetic activity.



This chart is updated every 15 minutes at 1, 16, 31, and 46 minutes past the hour. Use the browser Refresh or Reload option to ensure the latest data is shown. Boulder, Colorado and Fredericksburg, Virginia are mid-latitude stations. College, Alaska is a high-latitude station. Estimated Planetary is a combined measure of several mid- and high-latitude stations.

K-index Warnings are issued when a Boulder K-indices of 4, 5, 6, and 7 or greater is expected.
K-index Alerts are issued when the Boulder K-index reaches 4, 5, 6, 7, 8, or 9 in a 3-hour period.


Current Auroral Activity



This plot shows the current extent and position of the auroral oval in the northern/southern hemisphere, extrapolated from measurements taken during the most recent polar pass of the NOAA POES satellite.

The red arrow in the plot, that looks like a clock hand, points toward the noon meridian.

The statistical pattern depicting the auroral oval is appropriate to the auroral activity level determined from the power flux observed during the most recent polar satellite pass. The power fluxes in the statistical pattern are color coded on a scale from 0 to 10 ergs .cm-2.sec-1 according to the color bar on the right. The pattern has been oriented with respect to the underlying geographic map using the current universal time, updated every ten minutes.

This presentation provides an estimate of the location, extent, and intensity of aurora on a global basis. For example, the presentation gives a guide to the possibility that the aurora is located near a given location in the northern hemisphere under the conditions that existed at the time of the most recent polar satellite pass.

Normalization factor (n)
A normalization factor of less than 2.0 indicates a reasonable level of confidence in the estimate of power. The more the value of n exceeds 2.0, the less confidence should be placed in the estimate of hemispheric power and the activity level.

The process to estimate the hemispheric power, and the level of auroral activity, involves using this normalization factor which takes into account how effective the satellite was in sampling the aurora during its transit over the polar region. A large (> 2.0) normalization factor indicates that the transit through the aurora was not very effective and the resulting estimate of auroral activity has a lower confidence.

Instruments on board the NOAA Polar-orbiting Operational Environmental Satellite (POES) continually monitor the power flux carried by the protons and electrons that produce aurora in the atmosphere. SEC has developed a technique that uses the power flux observations obtained during a single pass of the satellite over a polar region (which takes about 25 minutes) to estimate the total power deposited in an entire polar region by these auroral particles. The power input estimate is converted to an auroral activity index that ranges from 1 to 10.

Current D-Region Absorption Prediction

Current 3-day Solar X-Ray Flux

Geomagnetic Indices

Fredericksburg, Boulder, College, and Estimated Planetary A and K Indices: The daily 24-hour A index and eight 3-hourly K indices from the Fredericksburg and Boulder (middle-latitude), and College (high-latitude) USGS stations monitoring Earth's magnetic field.
The estimated planetary 24 hour A index and eight 3-hourly K indices are derived in real time from a network of western hemisphere ground-based magnetometers.
K indices range from 0 (very quiet) to 9 (extremely disturbed).
A indices range from 0 (very quiet) to 400 (extremely disturbed). An A index of 30 or greater indicates geomagnetic storm conditions.

Latest Geomagnetic A and K Indices

Latest WWV Geophysical Alert Message

NOAA Space Weather Scale for Geomagnetic Storms

Category

Effect

Physical measure

Average Frequency
(1 cycle = 11 years)

Scale

Descriptor

Duration of event will influence severity of effects

   

Geomagnetic Storms

Kp values*
determined every 3 hours
Number of storm events when Kp level was met;
(number of storm days)

G 5

Extreme

Power systems: : widespread voltage control problems and protective system problems can occur, some grid systems may experience complete collapse or blackouts. Transformers may experience damage.

Spacecraft operations: may experience extensive surface charging, problems with orientation, uplink/downlink and tracking satellites.

Other systems: pipeline currents can reach hundreds of amps, HF (high frequency) radio propagation may be impossible in many areas for one to two days, satellite navigation may be degraded for days, low-frequency radio navigation can be out for hours, and aurora has been seen as low as Florida and southern Texas (typically 40 geomagnetic lat.)**.

Kp = 9

4 per cycle
(4 days per cycle)

G 4

Severe

Power systems: possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.

Spacecraft operations: may experience surface charging and tracking problems, corrections may be needed for orientation problems.

Other systems: induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45 geomagnetic lat.)**.

Kp = 8, including a 9-

100 per cycle
(60 days per cycle)

G 3

Strong

Power systems: voltage corrections may be required, false alarms triggered on some protection devices.

Spacecraft operations: surface charging may occur on satellite components, drag may increase on low-Earth-orbit satellites, and corrections may be needed for orientation problems.

Other systems: intermittent satellite navigation and low-frequency radio navigation problems may occur, HF radio may be intermittent, and aurora has been seen as low as Illinois and Oregon (typically 50 geomagnetic lat.)**.

Kp = 7

200 per cycle
(130 days per cycle)

G 2

Moderate

Power systems: high-latitude power systems may experience voltage alarms, long-duration storms may cause transformer damage.

Spacecraft operations: corrective actions to orientation may be required by ground control; possible changes in drag affect orbit predictions.

Other systems: HF radio propagation can fade at higher latitudes, and aurora has been seen as low as New York and Idaho (typically 55 geomagnetic lat.)**.

Kp = 6

600 per cycle
(360 days per cycle)

G 1

Minor

Power systems: weak power grid fluctuations can occur.

Spacecraft operations: minor impact on satellite operations possible.

Other systems: migratory animals are affected at this and higher levels; aurora is commonly visible at high latitudes (northern Michigan and Maine)**.

Kp = 5

1700 per cycle
(900 days per cycle)

* Based on this measure, but other physical measures are also considered.
** For specific locations around the globe, use geomagnetic latitude to determine likely sightings


NOAA Space Weather Scale for Solar Radiation Storms

Category

Effect

Physical measure

Average Frequency
(1 cycle = 11 years)

Scale

Descriptor

Duration of event will influence severity of effects

   

Solar Radiation Storms

Flux level of >= 10 MeV particles (ions)*

Number of events when flux level was met (number of storm days**)

S 5

Extreme

Biological: unavoidable high radiation hazard to astronauts on EVA (extra-vehicular activity); high radiation exposure to passengers and crew in commercial jets at high latitudes (approximately 100 chest x-rays) is possible.

Satellite operations: satellites may be rendered useless, memory impacts can cause loss of control, may cause serious noise in image data, star-trackers may be unable to locate sources; permanent damage to solar panels possible.

Other systems: complete blackout of HF (high frequency) communications possible through the polar regions, and position errors make navigation operations extremely difficult.

105

Fewer than 1 per cycle

S 4

Severe

Biological: unavoidable radiation hazard to astronauts on EVA; elevated radiation exposure to passengers and crew in commercial jets at high latitudes (approximately 10 chest x-rays) is possible.

Satellite operations: may experience memory device problems and noise on imaging systems; star-tracker problems may cause orientation problems, and solar panel efficiency can be degraded.

Other systems: blackout of HF radio communications through the polar regions and increased navigation errors over several days are likely.

104

3 per cycle

 

S 3

Strong

Biological: radiation hazard avoidance recommended for astronauts on EVA; passengers and crew in commercial jets at high latitudes may receive low-level radiation exposure (approximately 1 chest x-ray).

Satellite operations: single-event upsets, noise in imaging systems, and slight reduction of efficiency in solar panel are likely.

Other systems: degraded HF radio propagation through the polar regions and navigation position errors likely.

103

10 per cycle

 

S 2

Moderate

Biological: none.

Satellite operations: infrequent single-event upsets possible.

Other systems: small effects on HF propagation through the polar regions and navigation at polar cap locations possibly affected.

102

25 per cycle

S 1

Minor

Biological: none.

Satellite operations: none.

Other systems: minor impacts on HF radio in the polar regions.

10

50 per cycle

* Flux levels are 5 minute averages. Flux in particless-1ster-1cm-2. Based on this measure, but other physical measures are also considered.
** These events can last more than one day.


NOAA Space Weather Scale for Radio Blackouts

Category

Effect

Physical measure

Average Frequency
(1 cycle = 11 years)

Scale

Descriptor

Duration of event will influence severity of effects

   

Radio Blackouts

GOES X-ray peak brightness by class and by flux*

Number of events when flux level was met; (number of storm days)

R 5

Extreme

HF Radio:Complete HF (high frequency**) radio blackout on the entire sunlit side of the Earth lasting for a number of hours. This results in no HF radio contact with mariners and en route aviators in this sector.

Navigation: Low-frequency navigation signals used by maritime and general aviation systems experience outages on the sunlit side of the Earth for many hours, causing loss in positioning. Increased satellite navigation errors in positioning for several hours on the sunlit side of Earth, which may spread into the night side.

X20
(2 x 10-3)

Less than 1 per cycle

 

R 4

Severe

HF Radio: : HF radio communication blackout on most of the sunlit side of Earth for one to two hours. HF radio contact lost during this time.

Navigation: Outages of low-frequency navigation signals cause increased error in positioning for one to two hours. Minor disruptions of satellite navigation possible on the sunlit side of Earth.

X10
(10-3)

8 per cycle
(8 days per cycle)

 

R 3

Strong

HF Radio: Wide area blackout of HF radio communication, loss of radio contact for about an hour on sunlit side of Earth.

Navigation: Low-frequency navigation signals degraded for about an hour.

X1
(10-4)

175 per cycle
(140 days per cycle)

R 2

Moderate

HF Radio: Limited blackout of HF radio communication on sunlit side, loss of radio contact for tens of minutes.

Navigation: Degradation of low-frequency navigation signals for tens of minutes.

M5
(5 x 10-5)

350 per cycle
(300 days per cycle)

R 1

Minor

HF Radio: Weak or minor degradation of HF radio communication on sunlit side, occasional loss of radio contact.

Navigation: Low-frequency navigation signals degraded for brief intervals.

M1
(10-5)

2000 per cycle
(950 days per cycle)

* Flux, measured in the 0.1-0.8 nm range, in Wm-2. Based on this measure, but other physical measures are also considered.
** Other frequencies may also be affected by these conditions.


All information on this page compiled and copied from the webpages of the
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA), SPACE ENVIRONMENT CENTER (SEC)
For complete information, visit their website at: http://sec.noaa.gov




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The aurora borealis is seen over the town of Hyvinkaa in southern Finland October 31, 2003. The aurora is very visible as a result of a second huge magnetic solar storm hitting the Earth on Thursday, just a day after an earlier one hit our planet in what one astronomer called an unprecedented one-two punch. (Lehtikuva/Reuters)



This image photographed at about midnight Alaska Standard time, October 30, 2003 shows aurora over the Matanuska glacier and the Chugach mountains in the Southeast sky. The Matanuska glacier is about 100 miles Northeast of Anchorage. Without any moon, the glacier doesn't show very well. A second huge magnetic solar storm hit Earth Thursday, just a day after an earlier one hurtled into the planet in what one astronomer called an unprecedented one-two punch. 'It's like the Earth is looking right down the barrel of a giant gun pointed at us by the sun ... and it's taken two big shots at us,' said John Kohl of the Harvard-Smithsonian Center for Astrophysics in Massachusetts. (REUTERS/Calvin Hall/www.alaskasaurora.com)



This image photographed at about 6:00 Alaska Standard Time, October 29, 2003 shows aurora over Gunsight mountain located about 110 miles north east of Anchorage. This highly active aurora was photographed in the northwest sky. Powerful solar storms like this one cause a wide variety of aurora, in shape, color and motion. They also can appear in any part of the sky at this northern latitude, rather then the typical North sky. (REUTERS/Calvin Hall/www.alaskasaurora.com)

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