Solar Terrestrial Activity Report

Last update issued on March 4, 2003 at 03:50 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 3, 2003)]

Recent activity

The geomagnetic field was quiet to active on March 3. Solar wind speed ranged between 350 and 501 km/sec. A high speed coronal hole stream began to influence the solar wind from approximately 08h UTC with a slow and gradual increase in solar wind speed observed since then. The interplanetary magnetic field was occasionally strongly southwards after 1430 UTC.

Solar flux measured at 20h UTC on 2.8 GHz was 149.1. The planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 16.9).
Three hour interval K indices: 31233444 (planetary), 32323443 (Boulder).

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

At midnight there were 7 spotted regions on the visible disk, 1 of which has not yet been numbered by SEC/NOAA. Solar flare activity was low with only a single C class event recorded.

Region 10294 decayed slowly in the previously spotted sections. New spots emerged to the southwest. These spots may belong to a new region but has been included in this region until further development has been observed.
Region 10295 was mostly quiet and stable.
Region 10296 was quiet and added further spots in the very strong positive polarity section. M class flares are possible.
Region 10297 was quiet and stable.
New region 10298 emerged in the southeast quadrant.
[New region 10299 was split off from region 10296. This was a doubtful decision by SEC/NOAA as the spots in region 10299 appear to be the main negative polarity spots of region 10296.]
New region 10300 rotated into view at the northeast limb.

Spotted regions not yet numbered by SEC/NOAA:
[S117] A new region rotated into view at the southeast limb on March 2. Location at midnight: S25E61. Flare: C2.4 long duration event peaking at 21:05 UTC.

Coronal mass ejections (CMEs)

March 1-2: No obviously geoeffective CMEs observed.

March 3: A CME was observed after a long duration C2.4 event in and near region S117 late in the day. While most of the ejected material was observed off of the southeast limb, the LASCO C3 movie indicates that this was a full halo CME. Further details on this event will be added later on.

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 coronal hole (CH23) in the northern hemisphere with a trans equatorial extension was in a geoeffective position on March 1. A coronal hole (CH24) in the southern hemisphere was in a geoeffective position on March 2-3.

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


The geomagnetic field is expected to be unsettled to active until March 7 due to high speed streams from CH23 and 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 poor to fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Rafaela (both with weak signals)]

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.
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.

Solar region Date numbered SEC
Location at midnight Area Classification Comment
10292 2003.02.25 5   S09W92 0080 DAO rotated out of view
10293 2003.02.27     S17W24     plage
10294 2003.02.27 12 7 S07W13 0030 BXO classification was DRO
at midnight
10295 2003.02.27 6 6 S18E14 0050 CSO classification was CAO
at midnight
10296 2003.02.28 20 27 N11E35 0600 DKI classification was EKI
at midnight, STAR spot
count includes region
10297 2003.03.01 4 4 S16E43 0040 DAO classification was CSO
at midnight
10298 2003.03.03 5 7 S08E18 0020 DSO classification was DAO
at midnight
10299 2003.03.03 3   N12E47 0070 CAO only negative polarity
spots, these are the
trailing spots of region
10300 2003.03.03 1 1 N16E66 0010 AXX classification was HRX
at midnight
S114 emerged on
    S14W39     plage
S115 emerged on
    S19E05     now spotless
S116 emerged on
    N13W17     now spotless
S117 visible on
  1 S25E61 0010 AXX  
Total spot count: 56 53
SSN: 136 123

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)
2002.01 226.6 114.1 113.5 (-1.1)
2002.02 205.0 107.4 114.6 (+1.2)
2002.03 179.5 98.4 113.3 (-1.3)
2002.04 189.8 120.7 110.5 (-2.9)
2002.05 178.4 120.8 108.8 (-1.7)
2002.06 148.7 88.3 106.2 (-2.6)
2002.07 173.5 99.6 102.7 (-3.5)
2002.08 183.6 116.4 98.7 (-4.0)
2002.09 175.8 109.6 (94.7 predicted, -4.0)
2002.10 167.0 97.5 (91.2 predicted, -3.5)
2002.11 168.7 95.0 (86.0 predicted, -5.2)
2002.12 157.2 81.6 (81.6 predicted, -4.4)
2003.01 144.0 79.5 (78.6 predicted, -3.0)
2003.02 124.5 46.2 (73.6 predicted, -5.0)
2003.03 135.7 (1) 4.5 (2) (67.9 predicted, -5.7)

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.

[DX-Listeners' Club]