Solar Terrestrial Activity Report

Last major update issued on March 7, 2004 at 09:15 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 on March 6. Solar wind speed ranged between 347 and 438 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 104.5. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 6.5).
Three hour interval K indices: 22122221 (planetary), 13112222 (Boulder).

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

At midnight there were 4 spotted regions on the visible disk. Solar flare activity was moderate. A total of 7 C and 1 M class events was recorded during the day. 

Region 10567 decayed quickly losing two thirds of its penumbral area and most of the spots.
Region 10569 was quiet and stable.
Region 10570 rotated fully into view. There is a small magnetic delta structure at the eastern edge of the large leading penumbra. The region is complex with negative polarity areas in the east and in the west with several smaller areas of positive polarity in between. M class flares are possible.

Spotted regions not numbered by NOAA/SEC:
[S367] A new region emerged east of region 10569 on March 6. Location at midnight: S13E13.

Coronal mass ejections (CMEs)

March 4-6: 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 recurrent coronal hole (CH84) mostly in the northern hemisphere will likely reach a geoeffective position on March 7-10.

Processed SOHO/EIT 284 image at 19:06 UTC on March 6. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet on March 7-8 and most of March 9. Then a high speed stream from coronal hole CH84 will arrive and cause unsettled to major storm conditions, primarily on March 10-11. Unsettled to active is expected for March 12-13.

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to fair at sunrise, poor during nighttime. Propagation along long distance north-south paths is fair to good at sunrise, poor during nighttime. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). WLAM Lewiston ME was heard at sunrise, CPN Radio (Perú) was there as well. The sunrise opening was above average with many stations from the US east coast, the Caribbean and northern South America being heard].

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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.

Active region Date numbered SEC
Location at midnight Area Classification Comment
10567 2004.02.27 17 8 S12W55 0210 EAO classification was DAO
at midnight, area 0080
10569 2004.03.04 7 8 S11E03 0070 DAO  
10570 2004.03.05 7 19 S13E70 0340 CKO beta-gamma-delta
classification was FKO
at midnight
emerged on
  2 S13E13 0010 AXX  
Total spot count: 31 37
SSN: 61 77

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2003.02 124.5 46.0 78.3 (-2.5)
2003.03 131.4 61.1 74.0 (-4.3)
2003.04 126.4 60.0 70.1 (-3.9)
2003.05 115.7 55.2 67.6 (-2.5)
2003.06 129.3 77.4 65.0 (-2.6)
2003.07 127.7 83.3 61.8 (-3.2)
2003.08 122.1 72.7 60.0 (-1.8)
2003.09 112.2 48.7 (58.9 predicted, -1.1)
2003.10 151.7 65.5 (56.2 predicted, -2.7)
2003.11 140.8 67.3 (53.5 predicted, -2.7)
2003.12 114.9 46.5 (50.9 predicted, -2.6)
2004.01 114.1 37.2 (46.7 predicted, -4.2)
2004.02 107.0 46.0 (42.1 predicted, -4.6)
2004.03 100.0 (1) 10.5 (2) (39.7 predicted, -2.4)

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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.

[DX-Listeners' Club]