Solar Terrestrial Activity Report

Last update issued on June 22, 2003 at 03:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update June 3, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 3, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 3, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update April 13, 2003)]
[Archived reports (last update June 17, 2003)]

Recent activity

The geomagnetic field was unsettled to minor storm on June 21. Solar wind speed ranged between 472 and 564 km/sec under the influence of a high speed stream from coronal hole CH45.

Solar flux measured at 20h UTC on 2.8 GHz was 115.0. The planetary A index was 23 (STAR Ap - based on the mean of three hour interval ap indices: 23.8).
Three hour interval K indices: 44533433 (planetary), 23322532 (Boulder - source USAF).

The background x-ray flux is at the class B2 level.

At midnight there were 3 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events was recorded during the day.

Region 10386 decayed slowly and appears to have lost its magnetic delta structure. A minor M class flare is possible. Flares: C1.7 at 00:14 and C1.4 at 17:30 UTC.
Region 10387 increased its penumbral area further but remained fairly simply structured.
Region 10388 decayed slowly with most of the leading spots disappearing and the main penumbrae losing some area. Slow development was observed between the trailing and intermediate spot sections. Flares: C2.2 at 02:35 and C2.5 at 13:13 UTC.

Coronal mass ejections (CMEs)

June 19-21: No obviously geoeffective CMEs observed.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A new coronal hole (CH45) in the southern hemisphere was in a geoeffective position on June 18-19. A huge, recurrent coronal hole (CH46) mainly in the southern hemisphere but with trans equatorial extensions will rotate into a geoeffective position on June 25-29. A new coronal hole in the northern hemisphere is developing but is probably too far to the north to become geoeffective.

Processed SOHO EIT 284 image at 01:06 UTC on June 22. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to active on June 22-23 as a high speed stream from coronal hole CH45 dominates the solar wind. Quiet to unsettled is likely on June 24-26.

Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor and will likely stay very poor until at least June 24. Propagation along north-south paths is poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay.]

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions (Recent map)

Compare to the previous day's image.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SEC or where SEC has observed no spots.

Solar region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10385 2003.06.15 3   N28W49 0020 CSO now spotless
10386 2003.06.16 20 25 S07E04 0100 DAC beta-gamma
10387 2003.06.18 21 22 N18E23 0260 ESO classification was EAO
at midnight, area 0330
10388 2003.06.19 22 27 S03W19 0140 EAI beta-gamma
10389 2003.06.20 2   S12E01 0010 AXX now spotless
S186 emerged on
2003.06.17
    S18W58     plage
S187 emerged on
2003.06.17
    S22W39     plage
Total spot count: 68 74
SSN: 118 104

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2002.05 178.4 120.8 108.8 (-1.7)
2002.06 148.7 88.3 106.2 (-2.6)
2002.07 173.5 99.6 102.7 (-3.5)
2002.08 183.6 116.4 98.7 (-4.0)
2002.09 175.8 109.6 94.6 (-4.1)
2002.10 167.0 97.5 90.5 (-4.1)
2002.11 168.7 95.5 85.2 (-5.3)
2002.12 157.2 80.8 (81.4 predicted, -3.8)
2003.01 144.0 79.5 (78.3 predicted, -3.1)
2003.02 124.5 46.2 (73.3 predicted, -5.0)
2003.03 131.4 61.5 (67.6 predicted, -5.7)
2003.04 126.4 60.0 (62.7 predicted, -4.9)
2003.05 115.7 55.2 (57.8 predicted, -4.9)
2003.06 133.5 (1) 81.2 (2) (53.8 predicted, -4.0)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.


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