Last major update issued on February 1, 2005 at 01:55 UTC.
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The geomagnetic field was quiet to minor storm on January 31. Solar wind speed ranged between 478 and 775 km/sec under the influence of a high speed stream from CH142. A fairly quick increase in wind speed was observed 08-10h UTC. Solar wind temperature increased significantly as well.
Solar flux measured at 20h UTC on 2.8 GHz was 86.2. The planetary
A
index was 19 (STAR Ap - based on the mean of three hour interval ap
indices: 19.4).
Three hour interval K indices: 32345431 (planetary), 42344431 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was low. A single C class event was recorded during the day.
Region 10727 decayed further and was quiet.January 29-31: No obvious fully or partly Earth directed CMEs were observed. A full halo CME observed during the afternoon and early evening on January 30 most likely had a backsided source.
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 recurrent coronal hole in the northern hemisphere (CH142) was in a geoeffective position on January 27-29. A fairly small recurrent coronal hole (CH143) in the southern hemisphere will likely rotate to a geoeffective position on February 2-3.
Processed SOHO/EIT 284 image at 19:06 UTC on January 31. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on February 1 and inactive to quiet on February 2-4. A low speed stream from coronal hole CH143 could reach Earth on February 5 or 6 and cause a few unsettled and active intervals.
| 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) 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor to occasionally fair. Propagation along long distance north-south paths is very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: WLAM Lewiston ME. A number of stations from the Canadian Atlantic provinces and the easternmost parts of the USA were noted on other frequencies, WWZN on 1510 kHz had the best signal.
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 |
|---|---|---|---|---|---|---|---|
| 10727 | 2005.01.24 | 7 | 3 | S09W53 | 0110 | DAO | area was 0080 at midnight |
| 10728 | 2005.01.25 | 1 | S11W12 | 0000 | AXX | spotless | |
| 10729 | 2005.01.31 | 11 | 10 | S10E18 | 0070 | DSI |
formerly region S505 classification was DSO at midnight location: S10E16 |
| S504 | emerged on 2005.01.24 |
S12W88 | plage | ||||
| Total spot count: | 19 | 13 | |||||
| SSN: | 49 | 33 | |||||
| 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) |
| 2003.11 | 140.8 | 67.3 | 56.7 (-1.5) |
| 2003.12 | 114.9 | 46.5 | 54.8 (-1.9) |
| 2004.01 | 114.1 | 37.3 | 52.0 (-2.8) |
| 2004.02 | 107.0 | 45.8 | 49.3 (-2.7) |
| 2004.03 | 112.0 | 49.1 | 47.1 (-2.2) |
| 2004.04 | 101.2 | 39.3 | 45.5 (-1.6) |
| 2004.05 | 99.8 | 41.5 | 43.9 (-1.6) |
| 2004.06 | 97.4 | 43.2 | 41.7 (-2.2) |
| 2004.07 | 119.1 | 51.0 | (39.6 predicted, -1.9) |
| 2004.08 | 109.6 | 40.9 | (38.0 predicted, -1.6) |
| 2004.09 | 103.1 | 27.7 | (36.1 predicted, -1.9) |
| 2004.10 | 105.9 | 48.4 | (33.9 predicted, -2.2) |
| 2004.11 | 113.2 | 43.7 | (32.0 predicted, -1.9) |
| 2004.12 | 94.5 | 17.9 | (29.7 predicted, -2.3) |
| 2005.01 | 102.2 (1) | 52.0 (2) | (27.0 predicted, -2.7) |
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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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