Last major update issued on February 9, 2007 at 05:30 UTC.
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(last update February 6, 2007)]
The geomagnetic field was quiet to unsettled on February 8. Solar wind speed ranged between 438 and 506 km/s (average speed was 457 km/s, increasing 20 km/s over the previous day) under the influence of a weak coronal hole stream.
Solar flux measured at 20h UTC on 2.8 GHz was 78.4. The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.0). Three hour interval K indices: 23221211 (planetary), 22222222 (Boulder).
The background x-ray flux is at the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was low. A single C class event was recorded during the day. This was a C1.2 flare at 22:46 UTC.
Region 10941 was quiet and stable.
February 6-8: No obvious 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 (CH257) in the southern hemisphere has lost most of its area in the northwestern part. The main part of CH257 is currently 3 days rotation further east. The leading part of CH257 will be in an Earth facing position on February 8-9 while the main trailing part will face Earth on February 11-12.
Processed SOHO/EIT 195 image at 17:24 UTC on February 7. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet on February 9-10. Effects from CH257 could reach Earth on February 11-12 and cause some unsettled to active conditions. Unsettled to minor storm conditions are possible on February 14-15 as the high speed stream from the eastern part of CH257 becomes the main solar wind source.
| 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.
Daily monitoring will not resume until a local noise problem (related to construction work on a neighboring property) has been fixed. Occasional monitoring reports will be submitted when propagation is good.
February 7, 2007: Several strong signal from North America (particularly from stations on Newfoundland and from in and near New York) were heard in the lower half of the MW band during the night. Signals are, in general, much better than they were about a month ago.
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 |
|---|---|---|---|---|---|---|---|
| 10940 | 2007.01.25 | 1 | S05W97 | 0120 | HSX | rotated out of view early in the day | |
| 10941 | 2007.01.29 | 1 | 1 | S07W61 | 0110 | HSX | |
| S694 | 2007.02.07 | N14W19 | plage | ||||
| Total spot count: | 2 | 1 | |||||
| SSN: | 22 | 11 | |||||
| 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) |
| 2005.12 | 90.7 | 41.1 | 23.0 (-1.9) |
| 2006.01 | 83.4 | 15.3 | 20.8 (-2.2) |
| 2006.02 | 76.5 | 4.9 | 18.6 (-2.2) |
| 2006.03 | 75.4 | 10.6 | 17.3 (-1.3) |
| 2006.04 | 89.0 | 30.2 | 17.1 (-0.2) |
| 2006.05 | 80.9 | 22.2 | 17.3 (+0.2) |
| 2006.06 | 76.5 | 13.9 | 16.3 (-1.0) |
| 2006.07 | 75.7 | 12.2 | 15.3 (-1.0) |
| 2006.08 | 79.0 | 12.9 | (15.6 predicted, +0.3) |
| 2006.09 | 77.8 | 14.5 | (15.7 predicted, +0.1) |
| 2006.10 | 74.3 | 10.4 | (14.5 predicted, -1.2) |
| 2006.11 | 86.3 | 21.5 | (12.8 predicted, -1.7) |
| 2006.12 | 84.5 | 13.6 | (12.1 predicted, -0.7) |
| 2007.01 | 83.3 | 16.9 | (12.0 predicted, -0.1) |
| 2007.02 | 84.6 (1) | 8.0 (2) | (12.1 predicted, +0.1) |
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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