Solar Terrestrial Activity Report

Last update issued on June 8, 2003 at 03:25 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 1, 2003)]

Recent activity

The geomagnetic field was active to minor storm on June 7. Solar wind speed ranged between 573 and 758 km/sec under the influence of a high speed stream from coronal hole CH42.

Solar flux measured at 20h UTC on 2.8 GHz was 133.2. The planetary A index was 24 (STAR Ap - based on the mean of three hour interval ap indices: 25.3).
Three hour interval K indices: 44444445 (planetary), 34433335 (Boulder).

The background x-ray flux is at the class B7 level.

At midnight there were 7 spotted regions on the visible disk. Solar flare activity was low. A total of 11 C class events was recorded during the day. A C1.1 flare was observed in now spotless region S176 at 13:23 UTC.

Region 10373 was quiet and stable.
Region 10375 developed further and has at least 2 magnetic delta structures. M class flaring is likely and a major flare is possible. Flares: C2.6 at 02:19, C1.6 at 03:26, C2.3 at 09:42, C1.5 at 10:37, C1.8 at 11:12, C1.4 at 17:49 and C1.7 at 23:32 UTC
Region 10377 developed slowly and quietly.
Region 10378 decayed slowly and quietly.
New region 10380 rotated into view at the southeast limb on June 6 and was numbered by SEC the next day. This is a fairly complex region capable of producing at least minor M class flares. There is a magnetic delta structure in the main penumbra. Flares: C9.0 long duration event peaking at 00:52, C2.3 at 05:32 and C1.0 at 20:02 UTC.

Spotted regions not yet numbered by NOAA/SEC:
[S178] A new region emerged in the southwest quadrant on June 6 and developed slowly on June 7. Please note that SEC has made a major mistake in reassigning region number 10376 to this region. The spotless region 10376 was located at S11W57 at midnight. Location at midnight: S15W42.
[S180] A new region emerged in the southeast quadrant on June 7. Location at midnight: S07E14.

Coronal mass ejections (CMEs)

June 5-7: 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 huge recurrent coronal hole (CH42) in the southern hemisphere was in a geoeffective position on May 29-June 6.

Processed SOHO EIT 284 image at 01:06 UTC on June 8. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm on June 8-9 and quiet to active on June 10 due to a high speed stream from coronal hole CH42.

Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor and will likely stay poor to very poor until at least June 10. Propagation along north-south paths is fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Cidade AM from Brasil at first, then 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
10373 2003.05.27 1 1 N08W65 0070 HSX  
10375 2003.06.01 41 83 N12W04 0570 EKI beta-gamma-delta
classification was EKC
at midnight, area 0800
10376 2003.06.02 4   S11W57
(SEC:
S14W43)
0060 CHO location corrected
region is spotless,
SECs spots belong
to region S178,
SECs classification is
impossible with an
area of 0060. Very
poor observation by
SEC and USAF
10377 2003.06.04 7 17 N04E29 0070 DSO classification was ESO
at midnight
10378 2003.06.05 2 8 N17E44 0030 CRO classification was CSO
at midnight
10379 2003.06.06     S19W81     plage
10380 2003.06.07 10 23 S16E68 0400 EHO beta-gamma-delta
formerly region S179
classification was DKC
at midnight
S173 emerged on
2003.05.28
    N05W86     plage
S175 emerged on
2003.05.31
    N14W76     plage
S176 emerged on
2003.06.05
    N14W12     now spotless
S178 emerged on
2003.06.06
  4 S15W43 0030 DSO  
S180 emerged on
2003.06.07
  4 S07E14 0020 CRO  
Total spot count: 65 140
SSN: 125 210

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)
2003.06 118.0 (1) 19.1 (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]