Solar Terrestrial Activity Report

Last update issued on June 18, 2003 at 04:05 UTC. Minor update posted at 04:40 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 active to major storm on June 17. Solar wind speed ranged between 453 and 554 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 121.9. The planetary A index was 50 (STAR Ap - based on the mean of three hour interval ap indices: 52.6).
Three hour interval K indices: 56664444 (planetary), 64634243 (Boulder). [SEC have since June 11 been reporting faulty values for the Boulder K indices in their RSGA and SGAS products. They are using the data from the high latitude magnetometer at College, Alaska instead of the ones recorded at Boulder by USAF.  As of June 16 NOAA/SEC is claiming that the Boulder magnetometer is faulty. The K indices as reported by USAF are used in this report.]

The background x-ray flux is at the class B4 level.

At midnight there were 6 spotted regions on the visible disk. Solar flare activity was high. A total of 4 C and 1 M  class events was recorded during the day.

Region 10380 decayed further and was quiet.
Region 10385 developed slowly with most of the development occurring in the trailing spot section.
Region 10386 developed slowly with penumbral growth observed in the southernmost spots. Further major flares are possible. The region is currently a reversed polarity region. Flares: C1.5 at 01:02, C2.4 at 02:22, C1.1 at 06:05, C5.2/1F at 21:53 and a major long duration M6.8 event peaking at 22:55 UTC. The latter event was associated with a weak type IV and a moderate type II radio sweep.

Spotted regions not numbered by NOAA/SEC:
[S186] A new region emerged in the southern hemisphere near the central meridian on June 17. Location at midnight: S18W06.
[S187] A new region emerged in the southeast quadrant on June 17. Location at midnight: S22E13.
[S188] A new region rotated into view at the northeast limb on June 17. There are leading and trailing positive polarity areas with the negative polarity area in the middle. Location at midnight: N18E77.

Comment added at 04:40 UTC on June 18: A solar wind shock was observed at ACE at approximately 04:30 UTC. This is likely the arrival of the full halo CME observed on June 15-16.

Coronal mass ejections (CMEs)

June 15-16: The X1 flare in region 10386 late on June 15 was associated with an extremely wide full halo CME. The CME was very fast (estimated at just above 2000 km/sec) in its main eastwards direction, speeds in westerly directions were not as impressive. The CME will likely impact Earth during the latter half of June 17 and cause active to major storm conditions.

June 17: A fast partial halo CME was observed in LASCO C3 images after the major M class flare in region 10386 late in the day. The CME could become a full halo CME as it expands further and could reach Earth on June 19.

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 recurrent and well defined trans equatorial coronal hole (CH44) was in a geoeffective position on June 16-17. A new coronal hole (CH45) in the southern hemisphere is developing and will be in a geoeffective position on June 18-19.

Processed SOHO EIT 284 image at 19:06 UTC on June 17. Any black areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be active to major storm on June 18 due to CME effects. A high speed stream from coronal hole CH44 should dominate the solar wind from late on June 18 until  June 21 and cause unsettled to minor storm conditions. Another CME could arrive late on June 19 and increase geomagnetic disturbance levels to major storm.

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

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
Location at midnight Area Classification Comment
10380 2003.06.07 8 2 S15W64 0140 DSO classification was HAX
at midnight
10381 2003.06.09     S18W88     plage
10383 2003.06.11 7   N20W56 0020 BXO now spotless
10385 2003.06.15 8 15 N28E04 0050 CSO classification was DAO
at midnight, area 0100
10386 2003.06.16 17 24 S07E58 0310 DAI beta-gamma-delta
S185 emerged on
    S23W27     now spotless
S186 emerged on
  1 S18W06 0010 HRX  
S187 emerged on
  3 S22E13 0010 BXO  
S188 visible on
  7 N18E77 0050 DSO beta-gamma?
Total spot count: 40 52
SSN: 80 112

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)
2003.06 137.0 (1) 66.3 (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.

[DX-Listeners' Club]