Solar Terrestrial Activity Report

Last update issued on June 6, 2003 at 06:45 UTC. Images added at 10:04 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 quiet to unsettled on June 5. Solar wind speed ranged between 461 and 750 km/sec under the decreasing influence of a high speed stream from the western part of coronal hole CH42. The high speed stream from the eastern part of CH42 is dominating the solar wind early on June 6.

Solar flux measured at 20h UTC on 2.8 GHz was 113.6. The planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.5).
Three hour interval K indices: 33333332 (planetary), 23323232 (Boulder).

The background x-ray flux is at the class B5 level.

At midnight there were 7 spotted regions on the visible disk. Solar flare activity was low. A total of 3 C class events was recorded during the day. A C2.1 long duration event peaking at 10:19 UTC had its origin behind the southeast limb.

Region 10373 decayed further and lost its leader spot.
Region 10375 developed very quickly as new flux emerged in the leading spot section. At least one magnetic delta structure is forming and the region has become capable of producing major flares.. Flare: C1.7 at 17:34 and C1.0 at 23:37 UTC.
Region 10376 decayed further and is losing its trailing spots.
Region 10377 developed slowly and quietly.
New region 10378 rotated into view at the northeast limb.

Spotted regions not yet numbered by NOAA/SEC:
[S176] A new region emerged on June 5 west of region 10375. Location at midnight: N12E14.
[S177] A new region emerged on June 5 in the southwest quadrant. Location at midnight: S20W54.

Coronal mass ejections (CMEs)

June 3-5: 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 6. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be unsettled to minor storm June 6-9 due to a high speed stream from the eastern part of coronal hole CH42.

Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor and will likely stay poor to very poor until at least June 10. Propagation along north-south paths is good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, however, several other stations were observed, at least one of them from Argentina.]

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 4 1 N07W40 0110 CSO classification was HSX
at midnight
10375 2003.06.01 30 48 N12E24 0360 EAI beta-gamma-delta
classification was EKC
at midnight, area 0550
10376 2003.06.02 1 3 S11W30 0030 HSX classification was CSO
at midnight
10377 2003.06.04 7 6 N05E57 0070 DSO classification was DAO
at midnight
10378 2003.06.05 3 3 N16E69 0020 CSO  
S172 emerged on
2003.05.28
    S17W83     plage
S173 emerged on
2003.05.28
    N05W60     plage
S174 emerged on
2003.05.30
    N18W79     plage
S175 emerged on
2003.05.31
    N14W50     plage
S176 emerged on
2003.06.05
  2 N12E14 0010 AXX  
S177 emerged on
2003.06.05
  4 S20W54 0020 CAO  
Total spot count: 45 67
SSN: 95 137

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)
2003.06 113.3 (1) 11.7 (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.


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