Solar Terrestrial Activity Report

Last update issued on March 10, 2003 at 03:10 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 3, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 3, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 3, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
[Archived reports (last update March 10, 2003)]

Recent activity

The geomagnetic field was quiet to active on March 9. Solar wind speed ranged between 370 and 440 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 152.7. The planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 11.5).
Three hour interval K indices: 24312233 (planetary), 24421323 (Boulder).

The background x-ray flux is at the class B3-B4 level.

At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. A total of 5 C class events were recorded during the day.

Region 10296 decayed further losing all trailing spots.
Region 10297 decayed slowly and lost most of the small spots which had emerged the previous day. Flares: C2.6 at 00.07, C4.4 at 06:47, C1.6 at 15:20 and C1.2 at 21:01 UTC.
Region 10301 decayed further and could become spotless today.
Region 10305 developed early in the day, then began to decay.
Region 10306 had some small spots emerging just east of the huge penumbra, no other changes were noted. The spots in region 10308 appear to be the trailing spots of region 10306.
New region 10309 emerged early in the day near the northwest limb.
New region 10310 emerged in the southwest quadrant, just southwest of region 10297. Flare: C2.0 at 17:54 UTC.
New region 10311 emerged in the southeast quadrant.

Coronal mass ejections (CMEs)

March 7-9: No obviously geoeffective CMEs observed.

Coronal holes

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 well defined, large, recurrent coronal hole (CH25) will rotate into a geoeffective position on March 12-16.

Processed SOHO EIT 284 image at 19:06 UTC on March 8. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on March 10-14. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor, propagation along north-south paths is poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Cadena Peruana]

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.

Active solar regions (Recent map)

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.

Monthly solar cycle data

1) Running average based on the daily 20:00 UT observed solar flux value at 2800 MHz.
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.