Last update issued on July 29, 2003 at 03:30 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 minor storm on July 28. Solar wind speed ranged between 521 and 839 km/sec under the influence of a high speed stream from coronal hole CH49.
Solar flux measured at 20h UTC on 2.8 GHz was 103.4. The planetary A
index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 18.0).
Three hour interval K indices: 22345433 (planetary), 32344433 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 4 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded during the day.
Region 10414 decayed slowly and will rotate out of view at the southwest limb today.
Region 10420 was quiet and stable.
Region 10421 developed slowly and could produce further M class events. There is a magnetic delta structure in the southern part of the leading penumbra. Flare: C1.2 at 11:12 UTC. This region was the source of an impulsive M1.3 flare at 01:39 UTC on July 29.
Region 10422 developed quickly early in the day, then relaxed as the negative polarity area in the center of the region weakened. At this time the region does not seem capable of M class flaring. Flare: C1.0 at 13:49 UTC.
July 26-28: 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 - an extension of the southern polar coronal hole - was in a geoeffective position on July 24-29.
Processed GOES SXI coronal structure image at 23:53 UTC on July 28. 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 minor storm until August 2 due to a high speed stream from coronal hole CH49.
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 Cristal del Uruguay with additionally at least one station from Argentina heard.]
|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
|Location at midnight||Area||Classification||Comment|
area was 0060
|Total spot count:||16||34|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|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||130.6 (1)||126.2 (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.