Last update issued on July 25, 2003 at 04:25 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update July 21, 2003)]
The geomagnetic field was quiet to active on July 24. Solar wind speed ranged between 341 and 469 km/sec, gradually decreasing all day.
Solar flux measured at 20h UTC on 2.8 GHz was 125.2. The planetary A
index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.8).
Three hour interval K indices: 32102334 (planetary), 22212224 (Boulder).
The background x-ray flux is at the class B5 level.
At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. A total of 4 C class events was recorded during the day.
Region 10409 decayed quickly and will rotate out of view today. Flare: C1.4 at 01:23 UTC.
Region 10410 decayed quietly and is rotating over the southwest limb.
Region 10411 decayed slowly and quietly.
Region 10412 was quiet and rotated mostly out of view at the northwest limb.
Region 10414 added a few trailing spots and was quiet.
Region 10415 decayed quickly and had only a few tiny spots left by midnight, the region could become spotless today.
Region 10417 rotated out of view at the southwest limb. Flares: C1.6 at 02:49, C1.4 at 07:34
and C1.2 at 14:03 UTC.
Region 10419 developed slowly early in the day, then decayed and could soon become spotless.
New region 10420 rotated into view at the northeast limb.
July 22-24: No potentially 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 large coronal hole (CH49) in the southern hemisphere will be in a geoeffective position on July 24-31.
Processed GOES SXI coronal structure image at 00:00 UTC on July 25. Base SXI image courtesy of NOAA/SEC. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on July 25 and most of July 26. A high speed stream from coronal hole CH49 will likely reach Earth on July 26 and cause unsettled to minor storm conditions until August 3.
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 to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. This station and other stations on other frequencies above 1350 kHz could be heard well over an hour after local sunrise.]
| 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 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 |
|---|---|---|---|---|---|---|---|
| 10409 | 2003.07.13 | 4 | 5 | N14W76 | 0040 | CSO |
area was 0020 at midnight |
| 10410 | 2003.07.13 | 12 | 14 | S13W79 | 0580 | EKO | |
| 10411 | 2003.07.15 | 1 | 2 | N13W54 | 0030 | HSX | |
| 10412 | 2003.07.16 | 1 | 1 | N15W85 | 0040 | HAX | |
| 10413 | 2003.07.16 | N20W58 | plage | ||||
| 10414 | 2003.07.17 | 4 | 4 | S04W20 | 0130 | CAO | |
| 10415 | 2003.07.19 | 2 | 3 | N11W39 | 0040 | HAX |
classification was CRO at midnight, area 0010 |
| 10417 | 2003.07.20 | 5 | S22W91 | 0110 | CSO | rotated out of view | |
| 10418 | 2003.07.20 | 1 | S05W64 | 0010 | AXX | spotless | |
| 10419 | 2003.07.23 | 3 | 3 | N11E50 | 0010 | BXO | |
| 10420 | 2003.07.24 | 1 | 1 | N11E79 | 0040 | HAX | |
| Total spot count: | 34 | 33 | |||||
| SSN: | 134 | 113 | |||||
| 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) |
| 2002.06 | 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 | 82.0 (-3.2) |
| 2003.01 | 144.0 | 79.7 | (79.7 predicted, -2.3) |
| 2003.02 | 124.5 | 46.0 | (74.7 predicted, -5.0) |
| 2003.03 | 131.4 | 61.1 | (69.0 predicted, -5.7) |
| 2003.04 | 126.4 | 60.0 | (64.1 predicted, -4.9) |
| 2003.05 | 115.7 | 55.2 | (59.2 predicted, -4.9) |
| 2003.06 | 129.3 | 77.4 | (55.2 predicted, -4.0) |
| 2003.07 | 134.9 (1) | 118.2 (2) | (51.6 predicted, -3.6) |
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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