Last major update issued on August 3, 2006 at 04:50 UTC.
[Solar and
geomagnetic data - last month (updated daily)]
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electron fluence charts (updated daily)]
[Solar cycles 21-23
(last update July 19, 2006)]
[Solar cycles 1-20]
[Graphical comparison
of cycles 21, 22 and 23 (last update July 19, 2006)]
[Graphical
comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 19, 2006)]
[Historical solar and
geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update
July 9, 2006)]
The geomagnetic field was quiet to unsettled on August 2. Solar wind speed ranged between 479 and 585 km/s (all day average 549 km/s - decreasing 23 km/s from the previous day) under the slowly decreasing influence of a high speed stream from CH234.
Solar flux measured at 20h UTC on 2.8 GHz was 72.1. The planetary A index
was 10 (STAR Ap - based on the mean of three hour interval ap
indices: 9.6).
Three hour interval K indices: 32332113 (planetary), 32332112 (Boulder).
The background x-ray flux is at the class A1 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10901 redeveloped a spot and will be rotating out of view at
the northwest limb today.
Region 10902 decayed slowly and will be rotating out of view at the
southwest limb today.
July 31 - August 2: No partly or fully Earth directed CMEs were detected in LASCO imagery.
Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A recurrent coronal hole (CH235) in the southern hemisphere (with a trans equatorial extension) will be in an Earth facing position on August 2-4.
Processed SOHO/EIT 284 image at 01:06 UTC on August 3. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on August 3 due to lingering effects from CH234 and mostly quiet on August 4. A high speed stream from CH235 could arrive during the latter half of August 5 and cause quiet to active conditions until August 7.
| 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. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor to fair. From 02 to 03h UTC quite a few stations from the easternmost parts of North America were audible with fair to good signals.The best signals were noted from 780 CFDR and 1510 WWZN. From 03:10 to 03:50 UTC stations from Venezuela (in particular 1290 Puerto Cabello which had an excellent signal) and Cuba (840, 890, 910 and 1180 kHz) enjoyed the best propagation. From 03:50 UTC and for about 25 minutes stations from the southern part of South America had the edge with 700 Cadena 3 excellent at times. One surprise was 1330 Chaco Boreal AM (Paraguay).
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. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
| Active region | Date numbered | SEC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
|---|---|---|---|---|---|---|---|
| 10901 | 2006.07.22 | 1 | 1 | N08W73 | 0020 | AXX | classification was HRX at midnight |
| 10902 | 2006.07.30 | 1 | 2 | S09W74 | 0030 | CRO | classification was AXX and area 0010 at midnight |
| Total spot count: | 2 | 3 | |||||
| SSN: | 22 | 23 | |||||
| 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) |
| 2005.06 | 93.7 | 39.3 | 28.8 (-0.1) |
| 2005.07 | 96.4 | 40.1 | 29.1 (+0.3) |
| 2005.08 | 90.5 | 36.4 | 27.4 (-1.7) |
| 2005.09 | 91.1 | 21.9 | 25.8 (-1.6) |
| 2005.10 | 77.0 | 8.5 | 25.5 (-0.3) |
| 2005.11 | 86.3 | 18.0 | 24.9 (-0.6) |
| 2005.12 | 90.7 | 41.2 | 23.0 (-1.9) |
| 2006.01 | 83.4 | 15.4 | 20.8 (-2.2) |
| 2006.02 | 76.5 | 4.7 | (18.4 predicted, -2.4) |
| 2006.03 | 75.4 | 10.8 | (16.6 predicted, -1.8) |
| 2006.04 | 89.0 | 30.2 | (15.9 predicted, -0.7) |
| 2006.05 | 80.9 | 22.2 | (15.1 predicted, -0.8) |
| 2006.06 | 76.5 | 13.9 | (12.9 predicted, -2.2) |
| 2006.07 | 75.7 | 12.2 | (11.4 predicted, -1.5) |
| 2006.08 | 72.5 (1) | 1.1 (2) | (11.4 predicted, -0.0) |
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% lower.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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