Last update issued on March 14, 2003 at 04:20 UTC.
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[Solar cycles 21-23 (last update March 3, 2003)]
[Solar cycles 1-20]
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[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 3, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update January 27, 2003)]
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The geomagnetic field was quiet to active on March 13. Solar wind speed ranged between 427 and 509 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 134.2. The planetary A
index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.6).
Three hour interval K indices: 43334332 (planetary), 43334222 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight there were 5 spotted regions on the visible disk, 1 region has not yet been numbered by SEC/NOAA. Solar flare activity was low. Only 1 C class event was recorded during the day.
Region 10300 decayed slowly and could become spotless before rotating over the northwest limb.
Region 10306 did not change much and remains capable of producing occasional C or minor M class flares.
Region 10311 decayed further and is quickly losing its trailing positive polarity spots. Flare: C1.3 at 02:13 UTC.
New region 10313 emerged at a high latitude in the northeast quadrant near the central meridian.
Spotted regions not yet numbered by SEC/NOAA:
[S122] A new region emerged in the southeast quadrant during the last hours of the day and developed quickly. Small positive and negative polarity areas are scattered throughout the region. Location at midnight: S14E12.
March 11-13: No obviously geoeffective CMEs 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 well defined, huge, recurrent coronal hole (CH25) will rotate into a geoeffective position on March 11-18. This coronal hole has developed in the northwestern trans equatorial part (which is not as well defined as the main part of the coronal hole). A significant development is a new and large trans equatorial northeastern extension of CH25.
Processed SOHO EIT 284 image at 01:06 UTC on March 14. Any black areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly unsettled to active until March 21 due to a high speed coronal hole stream, some quiet intervals are likely on the first days of the perod. The strongest part of the disturbance is likely on March 18-21, particularly as the emergence of region S122 has cut off some of northern central part of CH25. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor, propagation along north-south paths is fair. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela) at first, then fading to be replaced by what was probably Radio Rafaela (Argentina).]
|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.
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.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. 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.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
classification was HSX
at midnight, area 0030
classification was EKO
at midnight. STAR
spot count includes
this is the trailing
negative polarity spots
of region 10306
classification was CRO
|Total spot count:||38||53|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2002.09||175.8||109.6||(94.7 predicted, -4.0)|
|2002.10||167.0||97.5||(91.2 predicted, -3.5)|
|2002.11||168.7||95.0||(86.0 predicted, -5.2)|
|2002.12||157.2||81.6||(81.6 predicted, -4.4)|
|2003.01||144.0||79.5||(78.6 predicted, -3.0)|
|2003.02||124.5||46.2||(73.6 predicted, -5.0)|
|2003.03||144.1 (1)||60.1 (2)||(67.9 predicted, -5.7)|
1) Running average based on the daily 20:00 UT observed solar flux value at 2800
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.