Last major update issued on July 19, 2005 at 04:00 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update July 2, 2005)]
The geomagnetic field was quiet to major storm on July 18. Solar wind speed ranged between 353 and 469 (all day average 414) km/sec under the influence of CME effects during the first half of the day.
Solar flux measured at 20h UTC on 2.8 GHz was 72.0. The planetary
index was 34 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 56633223 (planetary), 46632123 (Boulder).
The background x-ray flux is at the class A1-A2 level.
At midnight the visible solar disk was spotless. The solar flare activity level was very low. No C class events were recorded during the day.
July 16 and 18: No obvious partly or fully Earth directed CMEs were observed.
July 17: An impressive full halo CME was observed in LASCO C3 images starting at 12:18 UTC. Its source was in region 10786 well behind the northwest limb. A minor increase in proton levels was observed as well after this event.
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 well defined recurrent trans equatorial coronal hole (CH175) will rotate into an Earth facing position on July 17-19.
Processed SOHO/EIT 284 image at 01:06 UTC on July 19. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on July 19. Late on July 19 or early on July 20 a high speed stream from CH175 is likely to arrive and could cause unsettled to minor storm conditions until July 22.
|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 very poor. Propagation along long distance north-south paths is good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Rafaela Argentina. Lots of stations from Brazil were heard before local sunrise (i.e. both 1480 and 1540 kHz had several stations at unusually good signal levels), while stations from Argentina and Uruguay dominated after local sunrise.
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
|Location at midnight||Area||Classification||Comment|
|Total spot count:||0||0|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2005.01||102.2||31.3||(34.6 predicted, -0.6)|
|2005.02||97.2||29.1||(33.3 predicted, -1.3)|
|2005.03||89.9||24.8||(31.6 predicted, -1.7)|
|2005.04||86.0||24.4||(29.7 predicted, -1.9)|
|2005.05||99.3||42.6||(27.2 predicted, -2.5)|
|2005.06||93.7||39.3||(25.7 predicted, -1.5)|
|2005.07||103.6 (1)||56.5 (2)||(24.7 predicted, -1.0)|
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.