Solar Terrestrial Activity Report

Last update issued on August 22, 2003 at 03:35 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 1, 2003)]

Recent activity

The geomagnetic field was active to severe storm on August 21. Solar wind speed ranged between 507 and 864 km/sec, increasing all day under the influence of a high speed stream from coronal hole CH52.

Solar flux measured at 20h UTC on 2.8 GHz was 119.2. The planetary A index was 53 (STAR Ap - based on the mean of three hour interval ap indices: 56.9).
Three hour interval K indices: 45756555 (planetary), 45745545 (Boulder).

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

At midnight there were 5 spotted regions on the visible disk. Solar flare activity was low. A total of 2 C class events was recorded during the day. Region 10431 behind the southwest limb produced a C4.9 flare at 15:22 and a C1.4 flare at 17:31 UTC.

Region 10436 developed in the leading and intermediate spot sections and may be capable of producing a minor M class flare.
New region 10439 emerged in the northwest quadrant on August 20 and was numbered by SEC the next day.
New region 10440 emerged in the southeast quadrant on August 19 and was numbered two days later by SEC.
New region 10441 emerged in the northeast quadrant on August 20 and was numbered the next day by SEC.

Spotted regions not numbered by NOAA/SEC:
[S236] A new region is rotating into view at the southeast limb. Location at midnight: S11E81.

Coronal mass ejections (CMEs)

August 19-21: 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 large coronal hole (CH52) in the northern hemisphere will be in a geoeffective position on August 17-21, the eastern part is the most well defined part. A coronal hole (CH53) in the southern hemisphere does not currently appear likely to reach geoeffective positions.

Processed GOES SXI coronal structure image at 00:00 UTC on August 22. 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 unsettled to major storm until August 25 due to a high speed stream from coronal hole CH52.

Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor to useless. Propagation along north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, with a weak station from Brazil observed at times.]

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
10432 2003.08.13     S03W38     plage
10433 2003.08.14     S20W71     plage
10434 2003.08.15     S23W72     plage
10436 2003.08.17 21 24 N07E17 0170 ESI classification was EAI
at midnight
10437 2003.08.19     S22W52     plage
10438 2003.08.21 1   S31W31 0010 AXX formerly region S232
spotless
location was S31W35
at midnight
10439 2003.08.21 5 9 N08W23 0040 DSO formerly region S233
10440 2003.08.21 5 8 S08E12 0020 CSO formerly region S234
location was S08E06,
classification was CAO
and area 0040
at midnight
10441 2003.08.21 4 6 N12E48 0040 DSO formerly region S235
location was N12E46
at midnight
S230 emerged on
2003.08.17
    S03W47     plage
S236 visible on
2003.08.21
  4 S11E81 0050 CAO  
Total spot count: 36 51
SSN: 86 101

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)
2003.08 124.1 (1) 73.4 (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.


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