Solar Terrestrial Activity Report

Last update issued on June 17, 2003 at 03:15 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 10, 2003)]

Recent activity

The geomagnetic field was quiet to major storm on June 16. Solar wind speed ranged between 430 and 578 km/sec. While the disturbance which arrived at approximately 19h UTC on June 15 was not very impressive during the first hours after its arrival, the geomagnetic effects increased early on June 16 with minor storming observed. Activity decreased after noon but then another disturbance arrived. Both solar wind speed and the total field of the interplanetary magnetic field increased suddenly near 16:45 UTC. By 19h UTC solar wind speed had increased from 450 to 550 km/sec and later on leveled out between 520 and 540 km/sec. The new disturbance caused an increase in geomagnetic activity levels with major storming observed late in the day.

Solar flux measured at 20h UTC on 2.8 GHz was 122.6. The planetary A index was 32 (STAR Ap - based on the mean of three hour interval ap indices: 33.4).
Three hour interval K indices: 45254356 (planetary), 42143135 (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 USAF K indices are used in this report.]

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

At midnight there were 5 spotted regions on the visible disk. Solar flare activity was moderate. A total of 1 C and 2 M  class events was recorded during the day.

Region 10380 generally decayed. Some new spots emerged in the northern part of the region, however, only a few of those spots was visible towards the end of the day. Flare: C1.6 at 21:56 UTC.
Region 10383 reemerged with several spots.
Region 10385 added a few spots and was quiet.
Region 10386 rotated fully into view revealing a moderately large region with a magnetic delta structure in the western part of the largest penumbra. Further major flares are possible. The region is currently a reversed polarity region. Flares: M1.0 at 02:48 and M1.7 at 12:00 UTC.

Spotted regions not numbered by NOAA/SEC:
[S185] A new region emerged in the southwest quadrant early in the day and developed slowly. Location at midnight: S23W14. This is currently a reversed polarity region.

Coronal mass ejections (CMEs)

June 14: The erupting filament noted late on June 13 may have triggered activity in and near region 10380. SOHO EIT images display an apparent sequence of activity beginning with the filament eruption in the north, then an eruption in region 10380 and finally a filament eruption to the east southeast of region 10380. A faint full halo CME was observed in LASCO C3 images early in the day and may have been related to this activity. The distribution of the ejected material correlates fairly well with the location of the activity, however, we cannot disregard the possibility that the CME could be related to backside activity.

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.

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.

Processed SOHO EIT 284 image at 19:06 UTC on June 16. Any black areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be active to major storm on June 17-18 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.

Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor and will likely be very poor until at least June 22. Propagation along north-south paths is poor. [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
Location at midnight Area Classification Comment
10378 2003.06.05     N14W79     plage
10380 2003.06.07 16 8 S16W51 0160 DAI beta-gamma
classification was DSO
at midnight
10381 2003.06.09 1   S18W75 0040 HRX now spotless
10383 2003.06.11 1 7 N19W40 0000 AXX classification was CSO
at midnight, area 0030
10385 2003.06.15 10 11 N29E17 0070 DAO  
10386 2003.06.16 13 23 S07E71 0190 DAO beta-gamma-delta
classification was DAI
at midnight, area 0350
S185 emerged on
  4 S23W14 0020 CSO  
Total spot count: 41 53
SSN: 91 103

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)
2003.06 137.9 (1) 63.7 (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]