Solar Terrestrial Activity Report

Last update issued on March 1, 2003 at 03:00 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)]

Recent activity

The geomagnetic field was quiet to active on February 28. Solar wind speed ranged between 408 and 505 km/sec under the influence of a high speed stream.

Solar flux measured at 20h UTC on 2.8 GHz was 124.9. The planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 18.4).
Three hour interval K indices: 32343434 (planetary), 31343434 (Boulder).

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

At midnight there were 4 spotted regions on the visible disk, 1 of which has not yet been numbered by SEC/NOAA. Solar flare activity was low. A total of 5 C class events was recorded during the day. A spotless region near the northeast limb (and west northwest of region 10296) was the source of a C1.0 flare at 13:15 UTC. A region at or behind the southeast limb was the origin of a C1.5 flare at 00:37 and a C1.1 flare at 17:51 UTC (as well as a long duration C5.1 event peaking at 01:36 UTC on March 1).

Region 10294 decayed losing most of the small spots observed the day before.
Region 10295 was quiet and stable.
New region 10296 rotated partly into view on February 27 and was numbered the next day. This region has a large leading penumbra and may be capable of producing minor M class flares. Flare: C1.5 at 22:34 UTC.

Spotted regions not yet numbered by SEC/NOAA:
[S112] A new region emerged in the southwest quadrant on February 28. Location at midnight: S30W62.

Coronal mass ejections (CMEs)

February 27-28: 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

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 with a trans equatorial extension will rotate into a geoeffective position on March 1. A collection of smaller coronal holes (CH24) in the southern hemisphere could become geoeffective on March 2.

Processed SOHO EIT 284 image at 01:06 UTC on March 1. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on March 1-2 due to a high speed stream from a coronal hole (CH22). Another high speed stream stream (originating in CH23) could begin late on March 3 or early on March 4 and cause another episode of unsettled to active conditions until March 5 when this stream will be overlapped be a high speed stream from CH24. Quiet to unsettled conditions are likely from March 8. 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 to good. [Propagation conditions are currently monitored every night. Main monitoring frequency: 1470 kHz. Dominant station tonight: Several stations noted including Radio Vibración, Radio Cristal del Uruguay, CPN Radio and Radio Rafaela.]

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.