Solar Terrestrial Activity Report

Last update issued on June 23, 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 17, 2003)]

Recent activity

The geomagnetic field was unsettled to active on June 22. Solar wind speed ranged between 453 and 581 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 110.2. The planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 17.0).
Three hour interval K indices: 33433333 (planetary), 32321233 (Boulder - source USAF).

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

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

Region 10386 decayed slowly and quietly. There is still a magnetic delta structure in the center of the region. Although the region is small a minor M class flare is possible.
Region 10387 was quiet and stable. The region is magnetically simply structured and does not currently appear to be capable of producing any significant flares.
Region 10388 decayed quickly losing most of its penumbral area and quite a few spots. Flares: C1.0 at 09:49 and C1.2 at 21:46 UTC.
New region 10390 rotated into view at the northeast limb.

Spotted regions not numbered by NOAA/SEC:
[S191] A new bipolar region emerged in the northeast quadrant on June 22 southeast of the trailing spots of region 10387. Location at midnight: N14E17.

Coronal mass ejections (CMEs)

June 20-22: 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 25-30.

Processed SOHO EIT 284 image at 13:06 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 23 as a high speed stream from coronal hole CH45 dominates the solar wind. Quiet to unsettled is likely on June 24-27 becoming mostly unsettled to minor storm June 28 to July 4.

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 good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: none, several stations noted with most of them coming from Brazil. Radio Cristal del Uruguay was heard only occasionally.]

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     N28W62     plage
10386 2003.06.16 14 17 S06W08 0090 DAI beta-gamma-delta
10387 2003.06.18 21 28 N18E10 0270 EAO  
10388 2003.06.19 17 18 S02W32 0130 DAO  
10389 2003.06.20     S12W12     plage
10390 2003.06.22 2 4 N15E76 0080 DAI classification was DAO
at midnight
S186 emerged on
2003.06.17
    S18W71     plage
S187 emerged on
2003.06.17
    S22W52     plage
S191 emerged on
2003.06.22
  5 N14E17 0030 CSO  
Total spot count: 54 72
SSN: 94 122

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)
2003.06 132.4 (1) 84.3 (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]