Last update issued on April 3, 2003 at 03:50 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update 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 2. Solar wind speed ranged between 446 and 555 km/sec under the influence of a high speed stream from coronal hole CH28.
Solar flux measured at 20h UTC on 2.8 GHz was 157.5. The planetary A
index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 21.5).
Three hour interval K indices: 24444334 (planetary), 33444433 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight there were 9 spotted regions on the visible disk. Solar flare activity was low. A total of 6 C class events was recorded during the day.
Region 10321 lost all leader spots while slow development continued to the north of the largest trailing spot. C class
flaring is possible as the region has become somewhat more complex. Flare: C1.0 at 17:13 UTC.
Region 10323 decayed quickly losing more than half of the penumbral area.
Region 10324 was quiet and stable. Please observe that SEC/NOAA has this as region 10328 while their region 10324 is
region S129.
Region 10325 decayed slightly with all spots outside of the large penumbra disappearing.
Region 10326 was unchanged and quiet.
Region 10327 decayed slowly and quietly.
Spotted regions not yet numbered by SEC/NOAA:
[S129] A new region emerged northwest of region 10324 in the southeast quadrant on March 30. Location at midnight: S12W21.
Please note that SEC/NOAA has this as region 10324! Flares: C1.8 at 00:14, C1.1 at 12:36, C3.6
at 15:16, C1.1 at 21:36 and C1.0 at 22:45 UTC.
[S130] A new region emerged on April 2 south southeast of region 10325 with quite a few spots. Location at midnight:
N07E07.
[S131] A new region emerged in the northeast quadrant on April 2. Location at midnight: N01E30.
March 31-April 2: 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 6-7.
Processed SOHO EIT 284 image at 01:06 UTC on April 3. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on April 3-4 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 station tonight: Radio Vibración (Venezuela)]
| 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 | 1 | S13W76 | 0030 | HRX | now spotless | |
| 10319 | 2003.03.23 | 2 | N12W88 | 0120 | HSX | rotated out of view | |
| 10321 | 2003.03.24 | 14 | 13 | N07W40 | 0180 | DAO | beta-gamma |
| 10323 | 2003.03.25 | 26 | 21 | S07W56 | 0270 | EAI |
classification was DAI at midnight, area 0130 |
| 10324 | 2003.03.27 | 22 | 3 | S12W12 (SEC: S12W21) |
0120 | DAO |
location corrected, SECs spots are those of region S129 classification was AXX at midnight, area 0000 |
| 10325 | 2003.03.27 | 21 | 2 | N12E01 (SEC: N10E05) |
0310 | EHI |
location corrected SECs spots include those of region S130 classification was HHX at midnight, area 0300 |
| 10326 | 2003.03.28 | 2 | 2 | S11E09 | 0030 | HSX | |
| 10327 | 2003.03.31 | 6 | 4 | S05W38 | 0030 | CRO |
classification was DSO at midnight |
| 10328 | 2003.03.31 | 5 | S12W13 | 0010 | AXX |
this is actually region 10324 |
|
| S129 | emerged on 2003.03.30 |
30 | S12W21 | 0200 | DAI |
beta-gamma see comment for regions 10324, 10328 |
|
| S130 | emerged on 2003.04.02 |
15 | N07E07 | 0030 | DSO |
see comment for region 10325 |
|
| S131 | emerged on 2003.04.02 |
5 | N01E30 | 0030 | CSO | ||
| Total spot count: | 99 | 95 | |||||
| SSN: | 189 | 185 | |||||
| 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 | 155.3 (1) | 11.7 (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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