Information Kiosk

For those who would like to explore recent geomagnetic records and indices, there are several websites on the Internet that you can browse:

FIGURE 5.12 ► Major geomagnetic observatories are distributed throughout the world. Each has a three-letter code name for identification. Most observatories share their magnetic records by contributing copies to the World Data Centers located in those nations willing to fund their operations. Figure provided by the Geomagnetism Section, USGS.

FIGURE 5.12 ► Major geomagnetic observatories are distributed throughout the world. Each has a three-letter code name for identification. Most observatories share their magnetic records by contributing copies to the World Data Centers located in those nations willing to fund their operations. Figure provided by the Geomagnetism Section, USGS.

• Geomagnetism and Space Magnetism Kyoto University, Japan: http:// swdcdb.kugi.kyoto-u.ac.jp

• Geomagnetism Group British Geological Survey, UK: http://ub.nmh. ac.uk

• Geomagnetism Section U.S. Geological Survey, USA: http://geomag. usgs.gov

• Geophysical Institute University of Alaska, USA: http://maxwell.gi. alaska.edu

• National Geophysical Data Center NOAA, USA: http://www.ngdc. noaa.gov—select Solid Earth Geophys/magnetics

Several geostationary satellites, at a distance of about 6 Re over fixed locations of the Earth, and a special solar observer satellite (about 235 Re away in the Earth-Sun line, where various gravitational and centrifugal forces on

TABLE 5.1 ► NOAA Space Weather Scale: Geomagnetic Storms

Category

Effect"

Physical

Average frequency

measure'1

(1 cycle =11 years)e

Scale Descriptor

G5

Extreme

Power systems: grid systems can collapse and transformers experience damage.

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

Other systems: pipeline currents reach hundreds of amps, HF (high frequency) radio propagation impossible in many areas for one to two days, satellite navigation degraded for days, low-frequency radio navigation out for hours, and the aurora seen as low as the equator

II >0

4 per cycle (4 days per cycle)

G4

Severe

Power systems: possible voltage stability problems, portions of grids collapse and protective devices trip.

Kp = 8,

100 per cycle

Spacecraft operations: experience surface charging and tracking problems, orientation problems

including

(60 days per cycle)

need corrections.

a 9-

Other systems: induced pipeline currents affect preventive measures, HF radio propagation sporadic,

satellite navigation degraded for hours, low-frequency radio navigation disrupted, and the

aurora seen as low as the tropics.

G3

Strong

Power systems: voltage corrections required, false alarms triggered on protection devices, and

H £

200 per cycle

high "gas-in-oil" transformer readings likely.

Spacecraft operations: surface charging on satellite components, increased drag on satellite, and orientation problems need corrections.

Other systems: intermittent satellite navigation and low-frequency radio navigation problems, HF radio intermittent, and the aurora seen as low as mid-latitudes.

(130 days per cycle)

G2

Moderate

Power systems: high-latitude power systems affected.

Spacecraft operations: corrective actions required by ground control; changes in drag affect orbit predictions

Other systems: HF radio propagation fades at higher latitudes, and the auroraseen as low as 50 degrees.

Kp = 6

600 per cycle (360 days per cycle)

Gl

Minor

Power systems: weak power grid fluctuations. Spacecraft operations: minor impact on satellite operations

Other systems: the aurora seen at high latitudes (60 degrees); migratory animals begin to be affected.

Kp = 5

1700 per cycle (900 days per cycle)

"Some or all of these effects are possible.

bKp values (may change to use other measures, such as DST, as basis) determined every 3 hours. cNumber of storm events when Kp level was met (number of storm days).

"Some or all of these effects are possible.

bKp values (may change to use other measures, such as DST, as basis) determined every 3 hours. cNumber of storm events when Kp level was met (number of storm days).

TABLE 5.2 ► NOAA Space Weather Scale: Solar Radiation Storms

Category Effect" Physical Average frequency

Scale Descriptor

S5

Extreme

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

Satellite operations loss of some satellites, memory impacts cause loss of control, serious noise in image data, star-trackers unable to locate sources; permanent damage to solar panels. Other systems: No HF (high frequency) communications possible in the polar regions, and position errors make navigation operations extremely difficult.

105

Fewer than 1 per cycle

S4

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). Satellite operations: memory device problems, noise on imaging systems, star-trackers cause orientation problems, and solar panels degraded.

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

104

3 per cycle

S3

Strong

Biological: radiation hazard avoidance recommended for astronauts on EVA; passengers and crew in commerical jets at high latitudes receive low-level radiation (approximately 1 chest x-ray). Satellite operations: likely single-event upsets, noise in imaging systems, permanent damage to exposed components/detectors, and decrease of solar panel currents.

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

103

10 per cycle

S2

Satellite operations: infrequent single-event upsets.

Other systems: small effects on HF propagation through the polar cap and navigation at the polar cap impacted.

102

25 per cycle

SI

Minor

Biological: none. Satellite operations: none.

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

10

50 per cycle

"Some or all of these effects are possible.

''Flux level of >10 MeV particles (ions). Flux levels are 5 min averages. Flux in particles: s-1ster_1cm-2. cNumber of events when flux level was met (number of storm days; these events can last more than one day).

"Some or all of these effects are possible.

''Flux level of >10 MeV particles (ions). Flux levels are 5 min averages. Flux in particles: s-1ster_1cm-2. cNumber of events when flux level was met (number of storm days; these events can last more than one day).

TABLE 5.3 ► NOAA Space Weather Scale: Radio Blackouts

Category

Effect"

Physical

Average frequency

measure''

(1 cycle = 11 years)c

Scale

Descriptor

R5

Extreme

HF Radio: Complete HF (high frequency) radio blackout on the entire sunlit side of the Earth lasting for a number of hours. No HF radio contact with mariners or en route aviators. 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

R4

Severe

HF Radio-. HF radio communication blackout for one to two hours on most ofthe sunlit side

X10

8 per cycle

of Earth. HF radio contact lost during this time for mariners and en route aviators

( 10"3)

(8 days per cycle)

Navigation: Outages of low-frequency navigation signals cause increased error in positioning for

mariners and general aviators for one to two hours. Minor disruptions of satellite navigation

possible on the sunlit side of Earth.

R3

Strong

HF Radio: Wide area blackout of HF radio communication signals, loss of radio contact for mariners

XI

175 per cycle

and en route aviators for about an hour on sunlit side of Earth.

(10"4)

(140 days per cycle)

Navigation: Low-frequency navigation signals degraded for about an hour, affecting maritime

and general aviation positioning.

R2

Moderate

HF Radio: Limited blackout of HF radio communication signals on sunlit side, loss of radio contact

M5

350 per cycle

for tens of minutes for mariners and en route aviators.

(5 x 10~5)

(300 days per cycle)

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

and general aviation positioning.

R1

Minor

HF Radio: Weak or minor degradation of HF radio communication signals on sunlit side, occasional

Ml

2000 per cycle

loss of radio contact for mariners and en route aviators.

(IQ"5)

(950 days per cycle)

Navigation: Low-frequency navigation signals degraded for brief intervals affecting maritime

and general aviation positioning.

a Some or all of these effects are possible.

fcGOES X-ray peak brightness by class and by flux (flux, measured in the 0.1-0.8 nm range, in Wm-2). cNumber of events when flux level was met (number of storm days).

a Some or all of these effects are possible.

fcGOES X-ray peak brightness by class and by flux (flux, measured in the 0.1-0.8 nm range, in Wm-2). cNumber of events when flux level was met (number of storm days).

the satellite are appropriately balanced) collect particle, magnetic field, and radiation information to monitor the space environment. Such data, together with measurements from solar and magnetic observatories, are used by Space Environment Forecast Centers around the world to warn nations of the solar-terrestrial storms that impact modern life.

Information about the recent (and past) disturbances in the space environment between the Sun and the Earth can be explored ait the following websites:

• Geophysical Institute, University of Alaska, USA: http://www.pfrr. alaska.edu/~pfrr/AURORA/INDEX.HTML; also http://www.doc3. gi.alaska.edu

• Goddard Space Flight Center, NASA, USA: http://sohowww.nascom. nasa.gov/gallery/LASCO; also http://image.gsfc.nasa.gov/poetry; also http://www.spaceweather.com; also http://www-spof.gsfc. nasa.gov/Education/lntro.html

• IPS Radio and Space Services, Sydney, Australia: http://www.ips.gov. au

• Marshall Space Flight Center, NASA, USA: http://uvisun.msfc.nasa. gov/UVI/currentJmage.html

• Solar-Terrestrial Physics Division NGDC/NOAA, USA: http.V/www. ngdc.noaa.gov/stp/stp.html

• Space Environment Center, NOAA, USA: http://www.sec.noaa.gov

Crustal magnetic anomaly maps and global charts of the latest field models can be obtained from:

• Map and Book Sales, U.S. Geological Survey, Mailstop 306, Box 25286 Federal Center, Denver, Colorado 80225, USA; fax: 1-303-202-4693; e-mail: [email protected]

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