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)]
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
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.
August 19-21: No potentially geoeffective CMEs observed.
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.
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)|
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.
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
|Location at midnight||Area||Classification||Comment|
classification was EAI
formerly region S232
location was S31W35
|10439||2003.08.21||5||9||N08W23||0040||DSO||formerly region S233|
formerly region S234
location was S08E06,
classification was CAO
and area 0040
formerly region S235
location was N12E46
|Total spot count:||36||51|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|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.