Solar Terrestrial Activity Report

Last major update issued on March 4, 2004 at 04:15 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update March 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16, 2004)]
[Archived reports (last update March 3, 2004)]

Recent activity

The geomagnetic field was quiet to minor storm on March 3. Solar wind speed ranged between 566 and 747 km/sec under the influence of a high speed stream from coronal hole CH83.

Solar flux measured at 20h UTC on 2.8 GHz was 90.4. The planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 16.1).
Three hour interval K indices: 32254342 (planetary), 22243232 (Boulder).

The background x-ray flux is at the class B2 level.

At midnight there was 1 spotted region on the visible disk. Solar flare activity was very low. No C class events was recorded during the day. 

Region 10567 decayed in the leading spot section. A negative polarity area emerged quickly in the trailing spot section and a magnetic delta structure has formed in this part of the region. A minor M class flare is possible.

Coronal mass ejections (CMEs)

March 1-3: No partly or fully earth directed 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 recurrent trans equatorial coronal hole (CH83) was in a geoeffective position on February 26-29. A recurrent coronal hole (CH84) mostly in the northern hemisphere will likely reach a geoeffective position on March 7-8. A small coronal hole in the southern hemisphere is approaching the central meridian and may be numbered tomorrow.

Processed SOHO/EIT 284 image at 01:06 UTC on March 4. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on March 4-6.

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) with CPN Radio (Perú) gradually taking over the frequency].

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. When the high speed stream has arrived the color changes to green.
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 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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.

Monthly solar cycle data

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.