Solar Terrestrial Activity Report

Last update issued on August 30, 2003 at 04:10 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 quiet to active on August 29. Solar wind speed ranged between 427 and 677 km/sec under the influence of a high speed stream from coronal hole CH53.

Solar flux measured at 20h UTC on 2.8 GHz was 116.3. The planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.6).
Three hour interval K indices: 12143443 (planetary), 22243443 (Boulder).

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

At midnight there were 10 spotted regions on the visible disk. Solar flare activity was low. A total of 1 C class event was recorded during the day.

Region 10441 decayed further and had only a single small spot left at the end of the day.
Region 10442 was quiet and stable.
Region 10444 decayed slowly and quietly.
Region 10445 decayed slowly and quietly.
Region 10447 decayed and could become spotless today.
Region 10448 was quiet and displayed only minor changes in the layout of the spots.
Region 10449 was quiet and unchanged.
New region 10450 rotated into view at the southeast limb on August 28 and was numbered the next day by SEC. Flare: C1.0 at 19:59 UTC.

Spotted regions not numbered by NOAA/SEC:
[S245] This region emerged in the northwest quadrant on August 29. Location at midnight: N24W32.
[S246] A new region emerged near the center of the visible disk on August 29. Location at midnight: N10W05.

Coronal mass ejections (CMEs)

August 27-29: 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 with a trans equatorial extension, will rotate into a geoeffective position on August 29- September 2.

Processed GOES SXI coronal structure image at 00:00 UTC on August 30. 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 the first half of September 1. On September 1-5 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 stations tonight: Radio Vibración (Venezuela) and Radio Cristal del Uruguay].

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
10441 2003.08.21 1 1 N12W63 0020 HRX classification was AXX
at midnight, area 0000
10442 2003.08.22 1 2 S13W19 0090 HSX classification was CSO
at midnight
10443 2003.08.22     N14W85     plage
10444 2003.08.25 5 7 N09W20 0020 DSO classification was HRX
at midnight
10445 2003.08.25 6 7 N03W19 0070 DAO classification was DSO
at midnight, area 0000
10446 2003.08.27     S23E10     plage
10447 2003.08.28 4 3 N15W21 0010 CSO classification was HRX
at midnight
10448 2003.08.28 8 18 N19E18 0080 DAO  
10449 2003.08.28 3 4 S15E53 0140 DSO  
10450 2003.08.29 1 1 S18E66 0060 HSX formerly region S244
10451 2003.08.29 2   S10W65 0020 BXO formerly region S242
spotless
10452 2003.08.29 1   S09E05 0010 AXX formerly region S243
spotless
S237 emerged on
2003.08.24
    N24W77     plage
S245 emerged on
2003.08.29
  1 N24W32 0010 HRX  
S246 emerged on
2003.08.29
  1 N10W05 0010 AXX  
Total spot count: 32 45
SSN: 132 145

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)
2003.08 122.8 (1) 107.1 (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]