Last major update issued on July 30, 2007 at 04:35 UTC.
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The geomagnetic field was quiet to active on July 29. Solar wind speed ranged between 354 and 726 km/s (average speed was 495 km/s, increasing 140 km/s over the previous day) under the influence of a high speed stream from CH280.
Solar flux measured at 20h UTC on 2.8 GHz was 69.0. The planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.1). Three hour interval K indices: 34233233 (planetary), 34233333 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there were 2 spotted regiona on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10965 decayed and could soon become spotless.
Spotted regions not numbered by NOAA/SEC:
[S706] A new region emerged in the southwest quadrant on July 29. Location at midnight: S08W13.
July 27-29: No obvious fully or partly Earth directed CMEs were observed.
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 trans equatorial coronal hole (CH280) was in an Earth facing position on July 25-27. A new trans equatorial coronal hole (CH281) was in an Earth facing position on July 29-30.
Processed STEREO 195 image at 20:55 UTC on July 29. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor to fair.
Monitoring remarks from a location near N58E06: July 30: Some stations from Argentina, Brazil, Perú and Argentina were audible during the night, however, most signals were weak. At LSR 1470 kHz had a mix of Radio Cristal del Uruguay, CPN Radio and a station from Brazil. After LSR the strongest TA signal was that of 1500 kHz Radio Dos Mil.
The geomagnetic field is expected to be quiet to active on July 30 - August 3, first due to effects from CH280, later on replaced by CH281. Quiet conditions could return on August 4, then become quiet to active again on August 5-6 due to effects from CH282.
|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.
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|
|10965||2007.07.28||4||2||S11E10||0040||CSO||classification was AXX at midnight, area 0010|
|Total spot count:||4||4|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2007.01||83.3||16.9||(11.9 predicted, -0.2)|
|2007.02||77.7||10.6||(11.3 predicted, -0.6)|
|2007.03||72.2||4.8||(10.8 predicted, -0.5)|
|2007.04||72.4||3.7||(10.8 predicted, unchanged)|
|2007.05||74.4||11.7||(10.6 predicted, -0.2)|
|2007.06||73.7||12.0||(10.7 predicted, +0.1)|
|2007.07||71.8 (1)||14.8 (2)||(11.0 predicted, +0.3)|
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.