Last major update issued on March 25, 2007 at 01:35 UTC.
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update March 10, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update March 10, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update March 10, 2007)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update February 6, 2007)]
The geomagnetic field was quiet to minor storm on March 24. Solar wind speed ranged between 307 and 368 km/s (average speed was 340 km/s, increasing 25 km/s over the previous day) under the influence of a low speed stream from CH261. Solar wind density has been high since noon on March 24 as the high speed stream from CH262 is approaching Earth.
Solar flux measured at 20h UTC on 2.8 GHz was 72.8. The planetary A index was 21 (STAR Ap - based on the mean of three hour interval ap indices: 20.6). Three hour interval K indices: 45453112 (planetary), 44453212 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10947 decayed slowly and will rotate out of view at the southwest limb today.
March 22-24: No obvious fully or partially Earth directed CMEs were observed in LASCO imagery.
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
An elongated recurrent trans equatorial coronal hole (CH262) was in an Earth facing position on March 20-23.
Processed SOHO/EIT 195 image at 00:00 UTC on March 25. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to minor storm on March 25-27 due to effects from CH262.
|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.
Daily monitoring will not resume until a local noise problem (related to construction work on a neighboring property) has been fixed. Occasional monitoring reports will be submitted when propagation is good.
March 23, 2007: Strong signals were noted from a number of USA east coast stations. Some stations from the Canadian Atlantic provinces had signals exceeding S9 (on a Drake R8A).
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|
|10947||2007.03.23||1||2||S14W74||0020||HSX||classification was CSO at midnight|
|Total spot count:||1||2|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.09||77.8||14.4||(15.6 predicted, +0.0)|
|2006.10||74.3||10.4||(14.4 predicted, -1.2)|
|2006.11||86.3||21.5||(12.8 predicted, -1.6)|
|2006.12||84.5||13.6||(11.9 predicted, -0.9)|
|2007.01||83.3||16.9||(11.5 predicted, -0.4)|
|2007.02||77.7||10.6||(11.4 predicted, -0.1)|
|2007.03||71.8 (1)||6.4 (2)||(11.6 predicted, +0.2)|
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.