Space weather

Solar wind speed Solar wind magnetic fields Noon 10.7cm radio flux
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Update

Update

Update
ALERT
Geomagnetic K-index of 4
Issued: 2019-06-13 23.55 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 Jun 13 2355 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-06-13 23.48 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 Jun 13 2348 UTC
Valid To: 2019 Jun 14 0600 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-06-12 12.14 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 Jun 12 1213 UTC
Valid To: 2019 Jun 12 2100 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

CANCEL WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2019-06-09 13.27 UTC
Geomagnetic Storm Category G1 Predicted
Cancel Serial Number: 858
Original Issue Time: 2019 Jun 08 1757 UTC

Comment: Conditions no longer meet Watch criteria.

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

ALERT
Geomagnetic K-index of 5
Issued: 2019-06-08 18.47 UTC
Geomagnetic K-index of 5
Threshold Reached: 2019 Jun 08 1840 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2019-06-08 18.25 UTC
Geomagnetic K-index of 5 expected
Valid From: 2019 Jun 08 1824 UTC
Valid To: 2019 Jun 09 0600 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2019-06-08 17.57 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Jun 09: G1 (Minor) Jun 10: None (Below G1) Jun 11: None (Below G1)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-06-08 17.44 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3634
Valid From: 2019 Jun 08 1500 UTC
Now Valid Until: 2019 Jun 09 0600 UTC
Warning Condition: persisitence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Geomagnetic K-index of 4
Issued: 2019-06-08 17.21 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 Jun 08 1713 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2019-06-08 15.35 UTC
Geomagnetic K-index of 5 expected
Valid From: 2019 Jun 08 1534 UTC
Valid To: 2019 Jun 08 1800 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-06-08 15.00 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 Jun 08 1500 UTC
Valid To: 2019 Jun 08 2100 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2019-06-03 13.52 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2947
Begin Time: 2019 May 30 1535 UTC
Yesterday Maximum 2MeV Flux: 3771 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2019-06-02 09.02 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2946
Begin Time: 2019 May 30 1535 UTC
Yesterday Maximum 2MeV Flux: 5692 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2019-06-01 08.59 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2945
Begin Time: 2019 May 30 1535 UTC
Yesterday Maximum 2MeV Flux: 4446 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2019-05-31 08.59 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2944
Begin Time: 2019 May 30 1535 UTC
Yesterday Maximum 2MeV Flux: 1766 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2019-05-30 15.51 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 30 1535 UTC
Station: GOES-15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-05-29 08.53 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3632
Valid From: 2019 May 29 0328 UTC
Now Valid Until: 2019 May 29 1500 UTC
Warning Condition: Persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Geomagnetic K-index of 4
Issued: 2019-05-29 05.51 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 May 29 0551 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-05-29 03.28 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 May 29 0328 UTC
Valid To: 2019 May 29 0900 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2019-05-27 07.37 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 May 27 0736 UTC
Valid To: 2019 May 27 1200 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Table

Date Radio flux 10.7 cm SESC Sunspot number Sunspot area 10E-6 New regions GOES15 X-ray Bkgd flux Flares
X-ray Optical
C M X S 1 2 3
May 18, 2019 71 11 140 0 A7.9 0 0 0 0 0 0 0
May 19, 2019 68 0 0 0 A7.3 0 0 0 0 0 0 0
May 20, 2019 69 0 0 0 A6.7 0 0 0 0 0 0 0
May 21, 2019 68 0 0 0 A6.3 0 0 0 0 0 0 0
May 22, 2019 67 0 0 0 A6.3 0 0 0 0 0 0 0
May 23, 2019 67 0 0 0 A6.2 0 0 0 0 0 0 0
May 24, 2019 66 0 0 0 A6.3 0 0 0 0 0 0 0
May 25, 2019 67 0 0 0 A6.3 0 0 0 0 0 0 0
May 26, 2019 68 0 0 0 A6.3 0 0 0 0 0 0 0
May 27, 2019 68 0 0 0 A6.2 0 0 0 0 0 0 0
May 28, 2019 68 0 0 0 A6.5 0 0 0 0 0 0 0
May 29, 2019 68 0 0 0 A6.8 0 0 0 0 0 0 0
May 30, 2019 69 0 0 0 A7.3 0 0 0 0 0 0 0
May 31, 2019 69 0 0 0 A7.5 0 0 0 0 0 0 0
Jun 1, 2019 70 0 0 0 A7.8 0 0 0 0 0 0 0
Jun 2, 2019 70 0 0 0 A7.7 0 0 0 0 0 0 0
Jun 3, 2019 70 0 0 0 A7.3 0 0 0 0 0 0 0
Jun 4, 2019 70 0 0 0 A7.3 0 0 0 0 0 0 0
Jun 5, 2019 70 0 0 0 A7.3 0 0 0 0 0 0 0
Jun 6, 2019 69 0 0 0 A7.1 0 0 0 0 0 0 0
Jun 7, 2019 69 0 0 0 A7.1 0 0 0 0 0 0 0
Jun 8, 2019 68 0 0 0 A7.1 0 0 0 0 0 0 0
Jun 9, 2019 68 0 0 0 A6.8 0 0 0 0 0 0 0
Jun 10, 2019 69 0 0 0 A6.8 0 0 0 0 0 0 0
Jun 11, 2019 70 0 0 0 A7.0 0 0 0 0 0 0 0
Jun 12, 2019 70 0 0 0 A6.9 0 0 0 0 0 0 0
Jun 13, 2019 68 0 0 0 A6.9 0 0 0 0 0 0 0
Jun 14, 2019 68 0 0 0 A6.9 0 0 0 0 0 0 0
Jun 15, 2019 67 0 0 0 A6.8 0 0 0 0 0 0 0
Jun 16, 2019 66 0 0 0 A6.5 0 0 0 0 0 0 0
Average/Total 69 0 5 0 0 0 0 0 0 0 0

Summary graph

Flares

Solar wind

Solar Wind

The solar wind is a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons, protons and alpha particles with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature, and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy, from the high temperature of the corona and magnetic, electrical and electromagnetic phenomena in it.

The solar wind is divided into two components, respectively termed the slow solar wind and the fast solar wind. The slow solar wind has a velocity of about 400 km/s, a temperature of 1.4–1.6×10e6 K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s, a temperature of 8×10e5 K and it nearly matches the composition of the Sun's photosphere. The slow solar wind is twice as dense and more variable in intensity than the fast solar wind. The slow wind also has a more complex structure, with turbulent regions and large-scale structures.

Solar radio flux at 10.7 cm

Solar radio flux at 10.7 cm

The solar radio flux at 10.7 cm (2800 MHz) is an excellent indicator of solar activity. Often called the F10.7 index, it is one of the longest running records of solar activity. The F10.7 radio emissions originates high in the chromosphere and low in the corona of the solar atmosphere. The F10.7 correlates well with the sunspot number as well as a number of UltraViolet (UV) and visible solar irradiance records. Reported in “solar flux units”, (s.f.u.), the F10.7 can vary from below 50 s.f.u., to above 300 s.f.u., over the course of a solar cycle.

Flares

Flares

A solar flare is a sudden flash of brightness observed over the Sun's surface or the solar limb, which is interpreted as a large energy release of up to 6 × 10e25 joules of energy. They are often, but not always, followed by a colossal coronal mass ejection. The flare ejects clouds of electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two after the event.

Solar flares affect all layers of the solar atmosphere (photosphere, chromosphere, and corona), when the plasma medium is heated to tens of millions of kelvin, while the electrons, protons, and heavier ions are accelerated to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy is spread over frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. The same energy releases may produce coronal mass ejections (CME), although the relation between CMEs and flares is still not well established.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one every week when the Sun is "quiet", following the 11-year cycle (the solar cycle). Large flares are less frequent than smaller ones.

Classification

Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square metre, W/m2) of 100 to 800 picometre X-rays near Earth, as measured on the GOES spacecraft.

Classification Peak Flux Range at 100-800 picometer
W/m2
A < 10e-7
B 10e-7 to 10e-6
C 10e-6 to 10e-5
M 10e-5 to 10e-4
X 10e-4 to 10e-3
Z > 10e-3

An earlier flare classification is based on Hα spectral observations. The scheme uses both the intensity and emitting surface. The classification in intensity is qualitative, referring to the flares as: (f)aint, (n)ormal or (b)rilliant. The emitting surface is measured in terms of millionths of the hemisphere and is described below. (The total hemisphere area AH = 6.2 × 1012 km2.)

Classification Corrected area
(millionths of hemisphere)
S < 100
1 100 - 250
2 250 - 600
3 600 - 1200
4 > 1200

Sunspot number

Sunspots

Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They correspond to concentrations of magnetic field that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere. Sunspots usually appear in pairs, with pair members of opposite magnetic polarity. The number of sunspots varies according to the approximately 11-year solar cycle.

Sunspot populations quickly rise and more slowly fall on an irregular cycle of 11 years, although significant variations in the number of sunspots attending the 11-year period are known over longer spans of time. For example, from 1900 to the 1960s, the solar maxima trend of sunspot count has been upward; from the 1960s to the present, it has diminished somewhat. Over the last decades the Sun has had a markedly high average level of sunspot activity; it was last similarly active over 8,000 years ago.

The number of sunspots correlates with the intensity of solar radiation over the period since 1979, when satellite measurements of absolute radiative flux became available. Since sunspots are darker than the surrounding photosphere it might be expected that more sunspots would lead to less solar radiation and a decreased solar constant. However, the surrounding margins of sunspots are brighter than the average, and so are hotter; overall, more sunspots increase the Sun's solar constant or brightness. The variation caused by the sunspot cycle to solar output is relatively small, on the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W/m2 compared to 1366 W/m2 for the average solar constant).

K-indices



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Data


Estimated Planetary

Estimated Planetary

Date A K-indices (UTC)
0h 3h 6h 9h 12h 15h 18h 21h
May 19, 2019 3 0 0 1 1 1 1 0 2
May 20, 2019 6 3 2 1 1 1 1 1 1
May 21, 2019 4 1 2 1 1 2 0 0 1
May 22, 2019 4 0 1 2 1 1 1 1 1
May 23, 2019 5 1 1 1 2 1 1 1 2
May 24, 2019 5 1 2 1 1 1 1 2 2
May 25, 2019 4 1 1 0 1 1 1 2 2
May 26, 2019 5 1 1 1 0 1 1 1 3
May 27, 2019 10 3 3 3 2 1 3 2 1
May 28, 2019 8 1 1 2 2 2 2 3 3
May 29, 2019 14 3 4 3 3 2 2 3 3
May 30, 2019 8 3 2 2 2 2 1 2 2
May 31, 2019 5 2 2 2 1 1 1 0 1
Jun 1, 2019 3 1 0 1 0 1 1 1 1
Jun 2, 2019 4 2 1 0 0 1 1 1 1
Jun 3, 2019 4 1 1 0 2 1 1 1 1
Jun 4, 2019 7 2 2 2 2 2 2 2 2
Jun 5, 2019 4 2 1 1 0 1 1 1 1
Jun 6, 2019 3 1 1 1 1 1 0 1 0
Jun 7, 2019 4 1 1 1 1 2 1 1 1
Jun 8, 2019 18 1 1 0 2 3 4 5 4
Jun 9, 2019 6 3 2 2 1 1 1 1 1
Jun 10, 2019 3 1 1 0 1 1 1 1 1
Jun 11, 2019 3 1 1 1 1 1 0 1 1
Jun 12, 2019 4 1 2 1 1 1 1 1 0
Jun 13, 2019 10 1 2 2 2 3 2 2 4
Jun 14, 2019 8 3 2 3 2 2 1 1 1
Jun 15, 2019 4 1 2 2 2 1 1 0 1
Jun 16, 2019 4 1 2 1 1 1 1 0 1
Jun 17, 2019 3 0 1 1

Middle Latitude

Date A K-indices
May 19, 2019 3 0 0 1 1 2 1 1 2
May 20, 2019 7 3 2 2 1 2 1 2 2
May 21, 2019 4 1 2 1 1 2 1 1 1
May 22, 2019 5 0 1 2 2 2 2 1 1
May 23, 2019 5 1 1 1 2 2 2 1 2
May 24, 2019 6 1 2 1 2 2 2 2 2
May 25, 2019 3 1 0 1 1 1 1 2 1
May 26, 2019 6 1 1 1 1 2 2 2 3
May 27, 2019 12 2 3 4 2 3 3 2 1
May 28, 2019 9 1 0 2 2 3 2 3 3
May 29, 2019 16 3 4 4 3 2 2 3 3
May 30, 2019 8 3 2 2 2 2 2 2 2
May 31, 2019 5 2 2 2 1 2 1 1 1
Jun 1, 2019 4 1 0 1 1 2 2 1 2
Jun 2, 2019 4 2 0 0 1 2 2 2 1
Jun 3, 2019 5 1 0 1 2 2 2 2 2
Jun 4, 2019 8 2 1 2 2 2 2 3 2
Jun 5, 2019 5 2 1 1 1 2 1 2 1
Jun 6, 2019 4 0 1 1 1 2 1 2 1
Jun 7, 2019 6 1 0 1 1 3 2 2 2
Jun 8, 2019 14 1 1 0 2 3 4 4 4
Jun 9, 2019 8 4 2 1 2 2 1 1 1
Jun 10, 2019 4 0 0 0 1 3 2 2 1
Jun 11, 2019 3 1 1 0 1 2 1 1 1
Jun 12, 2019 5 1 1 2 2 2 2 1 1
Jun 13, 2019 12 1 2 2 2 4 2 2 4
Jun 14, 2019 13 4 2 3 2 4 2 2 1
Jun 15, 2019 6 1 1 2 2 2 2 1 2
Jun 16, 2019 6 1 2 1 1 2 3 1 1
Jun 17, 2019 1 1 1

High Latitude

Date A K-indices
May 19, 2019 1 0 0 1 0 0 0 0 1
May 20, 2019 3 2 2 2 1 0 1 0 0
May 21, 2019 2 1 0 0 0 2 0 0 1
May 22, 2019 2 0 1 1 2 1 0 0 1
May 23, 2019 4 2 1 0 3 1 1 0 1
May 24, 2019 3 1 2 1 0 1 1 1 1
May 25, 2019 1 0 0 0 0 1 0 1 1
May 26, 2019 1 1 0 0 0 0 0 0 1
May 27, 2019 14 3 3 4 4 3 2 1 0
May 28, 2019 4 1 1 1 1 1 1 2 2
May 29, 2019 28 4 4 6 5 4 2 1 2
May 30, 2019 13 3 3 2 5 2 2 1 1
May 31, 2019 5 2 2 3 2 2 0 0 0
Jun 1, 2019 1 1 1 1 0 0 0 0 0
Jun 2, 2019 1 1 1 0 0 0 0 0 0
Jun 3, 2019 3 1 0 0 2 2 1 0 1
Jun 4, 2019 11 2 2 4 3 2 3 2 1
Jun 5, 2019 2 2 1 1 1 0 0 0 0
Jun 6, 2019 1 1 0 1 0 0 0 0 0
Jun 7, 2019 2 0 0 2 1 0 1 0 0
Jun 8, 2019 10 1 1 0 1 2 4 4 2
Jun 9, 2019 5 2 3 2 1 2 0 1 0
Jun 10, 2019 1 1 1 0 0 0 0 0 1
Jun 11, 2019 1 2 1 0 0 0 0 0 0
Jun 12, 2019 1 1 1 0 2 0 0
Jun 13, 2019 13 1 1 2 3 5 3 2 2
Jun 14, 2019 15 3 2 5 3 4 1 1 1
Jun 15, 2019 4 1 2 2 3 1 0 0 0
Jun 16, 2019 2 1 2 1 0 0 0 1 0
Jun 17, 2019 0 0 0

About

The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label K comes from the German word Kennziffer meaning “characteristic digit”. The K-index was introduced by Julius Bartels in 1938.

The Estimated 3-hour Planetary Kp-index is derived at the NOAA Space Weather Prediction Center using data from the following ground-based magnetometers:

  • Sitka, Alaska
  • Meanook, Canada
  • Ottawa, Canada
  • Fredericksburg, Virginia
  • Hartland, UK
  • Wingst, Germany
  • Niemegk, Germany
  • Canberra, Australia

These data are made available thanks to the cooperative efforts between SWPC and data providers around the world, which currently includes the U.S. Geological Survey, Natural Resources Canada (NRCAN), the British Geological Survey, the German Research Centre for Geosciences (GFZ), and Geoscience Australia. Important magnetometer observations are also contributed by the Institut de Physique du Globe de Paris and the Korean Space Weather Center K-index Watches are issued when the highest predicted NOAA estimated Kp-indices for a day are K = 5, 6, 7, or >= 8 and is reported in terms of the NOAA G scale. K-index Warnings are issued when NOAA estimated Kp-indices of 4, 5, 6, and 7 or greater are expected. K-index Alerts are issued when the NOAA estimated Kp-indices reach 4, 5, 6, 7, 8, or 9.


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