Last update issued on September 4, 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 September 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update September 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update August 28, 2003)]
The geomagnetic field was unsettled to active on September 3. Solar wind speed ranged between 467 and 567 km/sec under the influence of a high speed stream from coronal hole CH54.
Solar flux measured at 20h UTC on 2.8 GHz was 110.4. The planetary A
index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.4).
Three hour interval K indices: 33343334 (planetary), 44343333 (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 very low.
Region 10448 decayed and will likely become spotless today.
Region 10450 was mostly unchanged. SEC finally merged this region with region 10449.
Spotted regions not numbered by NOAA/SEC:
[S247] A new region emerged on August 31 in the southwest quadrant and was mostly unchanged on September 1 and 2. Slow development was observed on September 3. Location at midnight: S09W69. Note that SEC has reused region 10452 for these spots.
[S249] This region emerged on September 3 in the southwest quadrant. Location at midnight: S23W29.
[S250] A new region emerged on September 3 in the southeast quadrant. This region currently has a magnetic delta structure and will have to watched for further development. Location at midnight: S09E37.
September 1-3: 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 recurrent coronal hole (CH54) in the northern hemisphere and with a trans equatorial extension, was in a geoeffective position on August 29- September 3. A trans equatorial coronal hole (CH55) will rotate into a geoeffective position on September 8.
Processed SOHO/EIT 284 image from 01:06 UTC on September 4. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm until September 6 under the influence of a high speed stream from coronal hole CH54.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to fair. Propagation along north-south paths is fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) and Radio Cristal del Uruguay].
|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|
|10442||2003.08.22||1||S12W86||0110||HSX||rotated out of view|
classification was AXX
at midnight, area 0000
spotless, the spots
belong to region S247
|2||S09W69||0040||DSO||see region 10452|
|Total spot count:||19||31|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.03||131.4||61.1||(74.2 predicted, -4.3)|
|2003.04||126.4||60.0||(69.3 predicted, -4.9)|
|2003.05||115.7||55.2||(64.4 predicted, -4.9)|
|2003.06||129.3||77.4||(60.4 predicted, -4.0)|
|2003.07||127.7||85.0||(56.9 predicted, -3.5)|
|2003.08||122.1||72.7||(53.9 predicted, -3.0)|
|2003.09||108.1 (1)||7.4 (2)||(51.9 predicted, -2.0)|
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.