Last major update issued on April 11, 2005 at 03:50 UTC.
[Solar and
geomagnetic data - last month (updated daily)]
[Solar wind and
electron fluence charts (updated daily)]
[Solar cycles 21-23
(last update April 4, 2005)]
[Solar cycles 1-20]
[Graphical comparison
of cycles 21, 22 and 23 (last update April 4, 2005)]
[Graphical
comparison of cycles 2, 10, 13, 17, 20 and 23 (last update April 4, 2005)]
[Historical solar and
geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports
(last update April 2, 2005)]
The geomagnetic field was quiet on April 10. Solar wind speed ranged between 316 and 341 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 88.3. The planetary
A
index was 4 (STAR Ap - based on the mean of three hour interval ap
indices: 4.0).
Three hour interval K indices: 10012211 (planetary), 10002111 (Boulder).
The background x-ray flux is at the class B1 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 10750 developed early in the day, then began to decay slowly.
Region 10751 developed further and rotated partly out of view at the southwest limb. Quite a bit of sub flare activity was
observed all day.
April 8-10: No obvious fully or partly Earth directed CMEs were 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 recurrent coronal hole (CH157) in the northern hemisphere will be in an earth facing position on April 9-10.
Processed SOHO/EIT 284 image at 19:06 UTC on April 10. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on April 11 and quiet to active on April 12-13 due to effects from CH157.
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 very poor. Propagation along long distance north-south paths is poor to very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) was audible at 02 UTC, no stations were heard after 03h UTC. Only a few stations from North America were noted around 02h UTC. KVNS on 1700 kHz was the most distant signal. After 03h UTC only CJYQ on 930 kHz was there with a weak 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 |
---|---|---|---|---|---|---|---|
10748 | 2005.03.31 | N11W70 | plage | ||||
10749 | 2005.04.03 | 1 | S06W30 | 0010 | AXX | spotless | |
10750 | 2005.04.05 | 6 | 4 | S07E12 | 0070 | DSO | |
10751 | 2005.04.08 | 5 | 1 | S07W83 | 0060 | DSO | classification was HAX at midnight |
S533 | 2005.04.09 | N19W15 | plage | ||||
Total spot count: | 12 | 5 | |||||
SSN: | 42 | 25 |
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) |
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 | 43.8 (-1.7) |
2004.06 | 97.4 | 43.2 | 41.6 (-2.2) |
2004.07 | 119.1 | 51.1 | 40.2 (-1.4) |
2004.08 | 109.6 | 40.9 | 39.2 (-1.0) |
2004.09 | 103.1 | 27.7 | 37.5 (-1.7) |
2004.10 | 105.9 | 48.0 | (35.6 predicted, -1.9) |
2004.11 | 113.2 | 43.5 | (33.9 predicted, -1.7) |
2004.12 | 94.5 | 17.9 | (31.6 predicted, -2.3) |
2005.01 | 102.2 | 31.3 | (28.9 predicted, -2.7) |
2005.02 | 97.2 | 29.1 | (26.5 predicted, -2.4) |
2005.03 | 89.9 | 24.8 | (24.7 predicted, -1.8) |
2005.04 | 85.3 (1) | 14.8 (2) | (22.9 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 some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
[DX-Listeners' Club] |