Solar Terrestrial Activity Report

Last update issued on August 29, 2003 at 04:00 UTC. 

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update August 18, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update August 18, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update August 18, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update August 28, 2003)]

Recent activity

The geomagnetic field was unsettled to active on August 28. Solar wind speed ranged between 400 and 489 km/sec, probably under the influence of a weak stream from coronal hole CH53.

Solar flux measured at 20h UTC on 2.8 GHz was 118.7. The planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.6).
Three hour interval K indices: 34443333 (planetary), 34443433 (Boulder).

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

At midnight there were 11 spotted regions on the visible disk. Solar flare activity was low. A total of 3 C class events was recorded during the day.

Region 10441 decayed quickly and could become spotless today or tomorrow..
Region 10442 decayed and lost the leader spots.
Region 10444 decayed slowly and quietly.
Region 10445 decayed losing spots and penumbral area. Flares: C1.3 at 13:35 (there was activity at the southeast limb at the same time) and C1.4 at 17:26 UTC.
Region 10446 decayed and could become spotless today.
New region 10447 emerged in the northeast quadrant to the north of region 10444 on August 27 and was numbered the next day by SEC. Slow decay was observed on August 28.
New region 10448 emerged on August 26 in the northeast quadrant and numbered two days later by SEC. The region developed slowly both on August 27 and 28.
New region 10449 rotated into view on August 27 at the southeast limb and was numbered the next day by SEC. No significant changes were observed on August 28. Flare: C1.0 at 08:42 UTC.

Spotted regions not numbered by NOAA/SEC:
[S242] This region emerged in the southwest quadrant on August 28. Location at midnight: S11W53.
[S243] A new region emerged in the southeast quadrant on August 28. Location at midnight: S08E17.
[S244] A new region rotated into view at the southeast limb on August 28 trailing region 10449. While this region currently appears to be a separate region it could be part of region 10449. Location at midnight: S17E79.

Coronal mass ejections (CMEs)

August 26-28: No potentially 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 coronal hole (CH54) in the northern hemisphere will rotate into a geoeffective position on August 30-31.

Processed GOES SXI coronal structure image at 00:00 UTC on August 29. Base SXI image courtesy of NOAA/SEC. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active until September 1. On September 2-3 a high speed stream from coronal hole CH54 will likely cause unsettled to minor storm conditions.

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

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 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.

Solar region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10436 2003.08.17 4   N07W80 0060 CRO spotless
10441 2003.08.21 11 6 N14W47 0040 DAO classification was CSO
at midnight, area 0020
10442 2003.08.22 3 2 S13W06 0080 CSO classification was HSX
at midnight
10443 2003.08.22     N14W72     plage
10444 2003.08.25 10 9 N09W06 0060 DAO  
10445 2003.08.25 11 7 N03W04 0060 DAO  
10446 2003.08.27 2 1 S23E23 0020 CRO classification was AXX
at midnight, area 0010
10447 2003.08.28 5 5 N16W05 0020 CSO formerly region S240
10448 2003.08.28 7 13 N19E34 0050 CSO formerly region S239
classification was DAO
at midnight, area 0080
10449 2003.08.28 3 5 S16E69 0080 DAO formerly region S241
S237 emerged on
2003.08.24
    N24W64     plage
S242 emerged on
2003.08.28
  4 S11W53 0020 CSO  
S243 emerged on
2003.08.28
  1 S08E17 0020 HSX  
S244 visible on
2003.08.28
  1 S17E79 0030 HSX  
Total spot count: 56 54
SSN: 146 164

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)
2002.07 173.5 99.6 102.7 (-3.5)
2002.08 183.6 116.4 98.7 (-4.0)
2002.09 175.8 109.6 94.6 (-4.1)
2002.10 167.0 97.5 90.5 (-4.1)
2002.11 168.7 95.5 85.2 (-5.3)
2002.12 157.2 80.8 82.0 (-3.2)
2003.01 144.0 79.7 81.0 (-1.0)
2003.02 124.5 46.0 (77.2 predicted, -3.8)
2003.03 131.4 61.1 (71.5 predicted, -5.7)
2003.04 126.4 60.0 (66.6 predicted, -4.9)
2003.05 115.7 55.2 (61.7 predicted, -4.9)
2003.06 129.3 77.4 (57.7 predicted, -4.0)
2003.07 127.7 85.0 (54.1 predicted, -3.6)
2003.08 123.0 (1) 102.9 (2) (52.3 predicted, -1.8)

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.


[DX-Listeners' Club]