Last update issued on April 4, 2003 at 04:00 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update April 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update April 2, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update April 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
[Archived reports (last update April 1, 2003)]
The geomagnetic field was quiet to active on April 3. Solar wind speed ranged between 435 and 482 km/sec under the influence of a high speed stream from coronal hole CH29.
Solar flux measured at 20h UTC on 2.8 GHz was 155.7. The planetary A
index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 15.0).
Three hour interval K indices: 32333334 (planetary), 33333333 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. A total of 14 C class events was recorded during the day.
Region 10321 developed new spots ahead of the largest trailing penumbra while spots north of that penumbra disappeared. C
flares are possible.
Region 10323 decayed further, particularly in the trailing spot section. The region will be rotating partially out of
view today.
Region 10325 was quiet and stable.
Region 10326 was unchanged and quiet.
New region 10329 emerged on April 2 and was numbered the next day. The region decayed on April 3 and could soon become
spotless.
New region 10330 rotated into view at the northeast limb.
Spotted regions not yet numbered by SEC/NOAA:
[S129] A new region emerged northwest of region 10324 in the southeast quadrant on March 30. A minor M class flare is
possible. Location at midnight: S12W34.
Please note that SEC/NOAA has this as region 10324! Flares: C3.6 at 01:41, C1.5 at 04:34, C1.0
at 06:58, C1.9 at 07:17, C6.5/1F at 10:27, C1.8 at 18:18, C1.7 at 19:10, C2.5 at 19:45 and C2.4 at 22:37 UTC.
[S130] A new region emerged on April 2 south southeast of region 10325 with quite a few spots. Slow decay was observed on
April 3. Location at midnight: N07W06.
April 1-3: 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 coronal hole (CH29) in the southern hemisphere was in a geoeffective position on March 30-31. A small coronal hole (CH30) in the southern hemisphere will likely rotate into a geoeffective position on April 5. Another coronal hole (CH31) in the southern hemisphere will probably be in a geoeffective position on April 6-8.
Processed SOHO EIT 284 image at 01:06 UTC on April 4. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on April 4 due to a high speed stream from coronal hole CH29 and quiet to unsettled on April 5-7. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor, propagation along north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) and Cadena Peruana de Noticias]
| Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
 |
 |
|
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 |
|---|---|---|---|---|---|---|---|
| 10318 | 2003.03.22 | S13W89 | plage | ||||
| 10321 | 2003.03.24 | 11 | 12 | N08W54 | 0140 | DAO | beta-gamma |
| 10323 | 2003.03.25 | 16 | 17 | S07W70 | 0240 | EAO |
classification was DAO at midnight, area 0080 |
| 10324 | 2003.03.27 | 21 | S12W25 (SEC: S11W35) |
0200 | DAI |
now spotless location corrected, SECs spots are those of region S129 |
|
| 10325 | 2003.03.27 | 11 | 3 | N12W11 (SEC: N11W09) |
0360 | DKO |
location corrected SECs spots include those of region S130 classification was CKO at midnight |
| 10326 | 2003.03.28 | 4 | 1 | S11W04 | 0030 | CSO |
classification was HSX at midnight |
| 10327 | 2003.03.31 | 6 | S04W53 | 0030 | CAO | now spotless | |
| 10328 | 2003.03.31 | S12W26 |
this is actually region 10324 |
||||
| 10329 | 2003.04.03 | 4 | 3 | N01E18 | 0020 | CSO | formerly region S131 |
| 10330 | 2003.04.03 | 1 | 1 | N07E74 | 0140 | HHX |
area was 0250 at midnight |
| S129 | emerged on 2003.03.30 |
23 | S12W34 | 0270 | DAI |
beta-gamma see comment for regions 10324, 10328 |
|
| S130 | emerged on 2003.04.02 |
8 | N07W06 | 0010 | BXO |
see comment for region 10325 |
|
| Total spot count: | 74 | 68 | |||||
| SSN: | 154 | 148 | |||||
| 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) |
| 2002.03 | 179.5 | 98.4 | 113.3 (-1.3) |
| 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 | (91.0 predicted, -3.6) |
| 2002.11 | 168.7 | 95.0 | (85.7 predicted, -5.3) |
| 2002.12 | 157.2 | 81.6 | (81.3 predicted, -4.4) |
| 2003.01 | 144.0 | 79.5 | (78.3 predicted, -3.0) |
| 2003.02 | 124.5 | 46.2 | (73.3 predicted, -5.0) |
| 2003.03 | 131.4 | 61.5 | (67.6 predicted, -5.7) |
| 2003.04 | 155.4 (1) | 16.8 (2) | (62.7 predicted, -4.9) |
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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