Last update issued on February 3, 2003 at 04:10 UTC. Minor update posted at 16:54 UTC.
[Solar and geomagnetic data
- last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
[Archived reports (last update February 3, 2003)]
The geomagnetic field was active to major storm on February 2. Solar wind speed ranged between 388 and 597 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 126.7. The planetary A
index was 45 (STAR Ap - based on the mean of three hour interval ap indices: 45.1).
Three hour interval K indices: 55556544 (planetary), 45544544 (Boulder).
The background x-ray flux is at the class B6 level.
At midnight there were 5 spotted regions on the visible disk, 2 of which has not yet been numbered by SEC/NOAA. Solar flare activity was low. A total of 7 C class flares were recorded during the day.
Region 10272 decayed quickly and will likely become spotless before rotating over the southwest limb late today.
Region 10274 was quiet and stable.
Region 10276 developed slowly and has a magnetic delta structure in the trailing spot section. Flares: C1.3 at 01:24, C2.8 at 03:34, C1.1 at 04:47, C1.4 at 05:43, C1.1 at 06:37, C1.4 at 09:10 and C1.0 at 15:33 UTC.
Spotted regions not yet numbered by SEC/NOAA:
[S86] A new region emerged in the southwest quadrant. Location at midnight: S18W09.
[S87] A new region emerged north of region 10274 a few days ago. Initially it was not clear if this was a separate region and the spots were associated with region 10274. Recent development of this region makes it obvious that there are two bipolar regions. Region 10274, which has a single negative spot, has an unspotted positive polarity area to its south and east. Region S87 in the north has narrowly separated positive and negative polarity areas, both with spots. Location at midnight: S04E03.
Comment added at 16:54 UTC on February 3: A coronal stream began to dominate the solar wind as early as 07h UTC today and the geomagnetic field has since been unsettled to active.
There are currently only three spotted regions on the visible disk, regions 10272 and S86 have become spotless.
January 31-February 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 large and well defined trans equatorial extension of the northern polar coronal hole will rotate into a geoeffective position on February 1-3.
Processed SOHO EIT 284 image at 19:06 UTC on January 31. [Due to a CCD bakeout the next image will likely be produced on February 4.] Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on February 3. A possibly strong coronal stream will likely begin to influence the geomagnetic field on February 4 and could cause unsettled to minor storm conditions until February 6 or 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 good.
|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
|Location at midnight||Area||Classification||Comment|
|10269||2003.01.21||1||S07W86||0050||HAX||rotated out of view|
classification was HSX
at midnight, area 0020
classification was HSX
SEC spot count
includes that of region
split off from region
|Total spot count:||21||34|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.08||183.6||116.4||(99.7 predicted, -3.0)|
|2002.09||175.8||109.6||(96.7 predicted, -3.0)|
|2002.10||167.0||97.5||(93.2 predicted, -3.5)|
|2002.11||168.7||95.0||(88.0 predicted, -5.2)|
|2002.12||157.2||81.6||(83.6 predicted, -4.4)|
|2003.01||144.0||79.5||(80.6 predicted, -3.0)|
|2003.02||126.3 (1)||4.9 (2)||(75.5 predicted, -5.1)|
1) Running average based on the daily 20:00 UT observed solar flux value at 2800
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.