Last update issued on May 8, 2003 at 02:50 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update May 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update May 1, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update April 13, 2003)]
[Archived reports (last update May 5, 2003)]
The geomagnetic field was unsettled to major storm on May 7. Solar wind speed ranged between 600 and 769 km/sec under the influence of a high speed stream from coronal hole CH38.
Solar flux measured at 20h UTC on 2.8 GHz was 110.2. The planetary A
index was 36 (STAR Ap - based on the mean of three hour interval ap indices: 38.3).
Three hour interval K indices: 55654433 (planetary), 54654433 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight there were 6 spotted regions on the visible disk. Solar flare activity was low. A total of 13 C class events was recorded during the day. An active region behind the northeast limb should soon rotate into view. This region produced a C2.2 flare at 10:27 and a C5.9 flare at 20:49 UTC and may be capable of minor M class flaring.
Region 10348 decayed further as it began to rotate over the southwest limb. A minor M class flare is possible today. Flares:
C1.2 at 00:48, C1.4 at 01:28, C1.3 at 02:56, C4.2 at 07:10, C2.3 at 10:54, C1.2 at 15:54 and C2.0 at 20:32 UTC.
Region 10349 decayed further as most of the region rotated out of view at the southwest limb. Flares:
C3.3 at 06:16, C1.8 at 13:12, C1.3 at 15:15 and C1.7 at 21:41 UTC.
Region 10351 was quiet and stable.
Region 10353 developed slowly adding a few small spots.
Region 10354 was quiet and stable.
Spotted regions not yet numbered by SEC/NOAA:
[S156] A new region emerged in the southeast quadrant on May 7. Location at midnight: S13E07.
May 5-7: No obviously geoeffective CMEs observed.
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 (CH38) in the southern hemisphere will be in a geoeffective position on May 2-9.
Processed SOHO EIT 284 image at 19:06 UTC on May 7. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm until May 11 due to a high speed stream from coronal hole CH38. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor (1510 WWZN Boston audible for a couple of hours) and will likely stay poor to very poor until at least May 12. Propagation along north-south paths is fair to good and is likely to be at least fair until May 12. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: At first a station from Brazil with soccer commentary, then Radio Cristal del Uruguay.]
| Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
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|
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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.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. 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 |
|---|---|---|---|---|---|---|---|
| 10346 | 2003.04.24 | 1 | N13W90 | 0060 | HSX | rotated out of view | |
| 10348 | 2003.04.26 | 15 | 14 | S34W80 | 0420 | FAI | beta-gamma |
| 10349 | 2003.04.26 | 14 | 2 | S14W86 | 0450 | EKI |
barely visible at midnight |
| 10351 | 2003.04.30 | 1 | 1 | N08W15 | 0200 | HSX | |
| 10352 | 2003.05.01 | S24W35 | plage | ||||
| 10353 | 2003.05.04 | 6 | 5 | S16W09 | 0010 | BXO |
classification was CRO at midnight |
| 10354 | 2003.05.04 | 1 | 2 | N19E21 | 0010 | AXX |
classification was HSX at midnight, area 0020 |
| 10355 | 2003.05.05 | 1 | 1 | N13E17 | 0010 | HRX | now spotless |
| S156 | emerged on 2003.05.07 |
1 | S13E07 | 0010 | AXX | ||
| Total spot count: | 39 | 26 | |||||
| SSN: | 109 | 96 | |||||
| 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) |
| 2002.04 | 189.8 | 120.7 | 110.5 (-2.9) |
| 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 | (84.9 predicted, -5.6) |
| 2002.12 | 157.2 | 80.8 | (80.5 predicted, -4.4) |
| 2003.01 | 144.0 | 79.5 | (77.5 predicted, -3.0) |
| 2003.02 | 124.5 | 46.2 | (72.4 predicted, -5.1) |
| 2003.03 | 131.4 | 61.5 | (66.8 predicted, -5.6) |
| 2003.04 | 126.4 | 60.0 | (61.9 predicted, -4.9) |
| 2003.05 | 134.6 (1) | 33.3 (2) | (57.9 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 (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% 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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