Last major update issued on June 1, 2005 at 04:30 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update May 6, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update May 6, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update May 6, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update May 15, 2005)]
The geomagnetic field was unsettled to active on May 31. Solar wind speed ranged between 445 and 511 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 96.3. The planetary
index was 17 (STAR Ap - based on the mean of three hour interval ap
Three hour interval K indices: 44333333 (planetary), 34333223 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 5 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 10767 decayed slowly and quietly.
Region 10769 reemerged with several spots and even developed penumbra on one of them, then began to decay again.
Region 10770 decayed quickly after the C flare. Flare: C2.4 at 14:42 UTC. A strong type II radio sweep was recorded in association with this flare.
Region 10771 lost the leader spot, however, the trailing spots developed slightly.
New region 10772 emerged in the southeast quadrant on May 30 and was numbered by SEC the next day. The region developed further and produced an M1.7 flare at 02:43 UTC on June 1.
May 29-31: No obvious fully or partly potentially geoeffective CMEs were observed.
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 coronal hole (CH168) in the southern hemisphere was in an Earth facing position on May 29. A recurrent coronal hole (CH169) in the northern hemisphere will rotate into an Earth facing position on June 1-3.
Processed SOHO/EIT 284 image at 13:06 UTC on May 31. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be unsettled to active on June 1-2 due to a high speed stream from CH168 and quiet to unsettled on June 3.
|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 to excellent. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Again many stations from Brazil and Argentina were audible in addition to Radio Cristal del Uruguay. Radio Champaquí (Argentina) on 1510 kHz had the best signal I've heard from them, however, there were other stations on that frequency as well.
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|
|10767||2005.05.21||12||14||S09W59||0170||EAO||classification was DSO at midnight, area 0110|
|10770||2005.05.29||5||2||N12W27||0010||BXO||classification was HRX at midnight, area 0020|
|10771||2005.05.30||4||2||N24W47||0030||CSO||classification was HSX at midnight|
formerly region S552
classification was DAI at midnight, area 0090
|Total spot count:||29||37|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.11||113.2||43.5||(34.8 predicted, -1.1)|
|2004.12||94.5||17.9||(33.4 predicted, -1.4)|
|2005.01||102.2||31.3||(30.9 predicted, -2.5)|
|2005.02||97.2||29.1||(28.3 predicted, -2.6)|
|2005.03||89.9||24.8||(26.5 predicted, -1.8)|
|2005.04||86.0||24.4||(24.6 predicted, -1.9)|
|2005.05||99.3 (1)||65.4 (2)||(22.0 predicted, -2.6)|
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.