Last update issued on February 27, 2003 at 03:40 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 24, 2003)]
The geomagnetic field was quiet to active on February 26. Solar wind speed ranged between 358 and 468 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 109.4. The planetary A
index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 17.6).
Three hour interval K indices: 12443334 (planetary), 12343324 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 5 spotted regions on the visible disk, 3 of which have not yet been numbered by SEC/NOAA. Solar flare activity was very low.
Region 10290 decayed quietly.
Region 10292 decayed slowly and quietly.
Spotted regions not yet numbered by SEC/NOAA:
[S108] A new region emerged early on February 26 near the southeast limb. Location at midnight: S06E55.
[S109] A new region emerged in the southeast quadrant early on February 26. Location at midnight: S20E40.
[S110] A new region rotated into view at the southeast limb. This region appears to be capable of C class flaring. Location at midnight: S19E76.
February 24: No obviously geoeffective CMEs observed.
No new LASCO images will become available until Feb.27 or 28 thus preventing CME analysis.
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 recurrent, trans equatorial coronal hole (CH21) was in a geoeffective position on February 23-24. The northernmost part of a coronal hole (CH22) in the southern hemisphere may have been geoeffective on February 26-27. A coronal hole (CH23) in the northern hemisphere will rotate into a geoeffective position on March 1.
Processed SOHO EIT 284 image at 01:06 UTC on February 27. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to minor storm on February 27 and quiet to active on February 28-March 2 due to high speed streams from coronal holes (CH21 and CH22). 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. [Propagation conditions are currently monitored every night. Main monitoring frequency: 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. After s/off several weak stations observed. On Febr.26 Rádio Mensagem, Jacarei (SP), Brazil was identified at 03h UTC.]
|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|
classification was CAO
at midnight, area 0090
classification was HSX
at midnight, area 0020
|Total spot count:||15||18|
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||124.8 (1)||82.4 (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.