Last update issued on August 23, 2003 at 04:30 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update August 18, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update August 18, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update August 18, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update August 1, 2003)]
The geomagnetic field was unsettled to major storm on August 22. Solar wind speed ranged between 749 and 944 km/sec under the influence of a high speed stream from coronal hole CH52.
Solar flux measured at 20h UTC on 2.8 GHz was 120.9. The planetary A
index was 43 (STAR Ap - based on the mean of three hour interval ap indices: 44.3).
Three hour interval K indices: 55556543 (planetary), 65544433 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 5 spotted regions on the visible disk. Solar flare activity was low. A total of 1 C class event was recorded during the day.
Region 10436 was mostly unchanged and may be capable of producing an isolated minor M class flare. Flare:
C1.9 long duration event peaking at 03:50 UTC.
Region 10439 did not change much and was quiet.
Region 10440 developed moderately quickly and is magnetically simply structured.
Region 10441 developed adding several spots and increasing its penumbral area significantly. There is not much separating the positive and negative polarity areas and the region could become interesting if further development occurs.
New region 10442 rotated fully into view at the southeast limb.
August 20-22: 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 (CH52) in the northern hemisphere was in a geoeffective position on August 17-21, the eastern part is the most well defined part. A coronal hole (CH53) in the southern hemisphere does not currently appear likely to reach geoeffective positions.
Processed GOES SXI coronal structure image at 22:24 UTC on August 22. 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 unsettled to major storm until August 25 due to a high speed stream from coronal hole CH52.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor to useless. 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, several other stations were observed as well.]
|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|
classification was EAI
at midnight, this is
not a compact region
classification was DAO
and area 0130
classification was DAO
and area 0070
|10442||2003.08.22||3||5||S12E65||0110||DAO||formerly region S236|
|Total spot count:||66||71|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.02||124.5||46.0||(77.2 predicted, -3.8)|
|2003.03||131.4||61.1||(71.5 predicted, -5.7)|
|2003.04||126.4||60.0||(66.6 predicted, -4.9)|
|2003.05||115.7||55.2||(61.7 predicted, -4.9)|
|2003.06||129.3||77.4||(57.7 predicted, -4.0)|
|2003.07||127.7||85.0||(54.1 predicted, -3.6)|
|2003.08||123.9 (1)||77.4 (2)||(52.3 predicted, -1.8)|
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 analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.