Solar Terrestrial Activity Report

Last update January 16, 2003 at 03:10 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 1, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 1, 2003)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 1, 2003)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update January 13, 2003)]

Recent activity

The geomagnetic field was quiet to unsettled on January 15. Solar wind speed ranged between 367 and 425 km/sec, under the influence of a weak coronal stream.

Solar flux measured at 20h UTC on 2.8 GHz was 149.9. The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 9.0).
Three hour interval K indices: 32223322 (planetary), 21222222 (Boulder).

The background x-ray flux is at the class B4 level.

At midnight there were 8 spotted regions on the visible disk. Solar flare activity was low. Only 1 C class event was recorded during the day.

Region 10247 decayed further. All of the trailing spots are likely to disappear today.
Region 10250 was quiet and unchanged.
Region 10251 decayed further losing penumbral area in the leading spots. The region was quiet.
Region 10254 was quiet and stable.

Region 10255 was split off from region 10251 on January 12 by SEC/NOAA. This split was doubtful even then and it is currently obvious that it was a premature decision.
Region 10256 was split off from region 10254 on January 12 by SEC/NOAA. Regions 10254 and 10256 make up one bipolar region with the negative polarity area in the west and the positive area to the east. It remains to be seen if SEC will merge the "two" regions again.

Region 10257 developed early in the day, then decayed again.
Region 10258 was quiet and stable.
Region 10259 did not change much and was mostly quiet. Flare: C1.2 at 09:24 UTC.
New region 10260 rotated into view at the northeast limb.

Coronal mass ejections (CMEs)

January 13-15: No obviously geoeffective CMEs observed.

Coronal holes

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 large trans equatorial coronal hole will rotate into a geoeffective position on January 19-22.

Processed SOHO EIT 284 image at 19:06 UTC on January 15. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be mostly quiet on January 16-19 with a few unsettled intervals likely early in the period. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair becoming fair to good.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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.

Active solar regions (Recent map)

Composite image based on a SOHO/MDI continuum image and overlaid by a coronal hole image. Region numbering has been included. 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
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10245 2003.01.03     N12W85      
10247 2003.01.06 10 5 S16W46 0070 DSO classification was CSO
at midnight, area 0040
10249 2003.01.07 2   S14W85 0030 AXX actually spotless
10250 2003.01.07 5 3 S24W24 0150 CAO  
10251 2003.01.07 14 12 S14W20
(SEC:
S15W14)
0050 CRO classification was ESO
at midnight, area 0200,
region 10255 included
10252 2003.01.09     S03W21     plage
10254 2003.01.10 5 4 S14E10
(SEC:
S15E04)
0120 CSO location corrected,
classification was ESO
at midnight, area 0140.
STAR spot count
includes region 10256.
Only negative polarity
spots in leading section
10255 2003.01.12 13   S13W23 0160 CAO split off from region
10251
10256 2003.01.12 1   S17E16 0050 HSX split off from region
10254. A single
positive polarity spot.
10257 2003.01.13 4 2 N16W03 0020 CSO  
10258 2003.01.14 5 2 N07E44 0060 CSO  
10259 2003.01.14 3 3 N11E58 0030 HSX  
10260 2003.01.15 1 1 N14E77 0070 HSX  
S73 emerged on
2003.01.13
  S21W56      plage
Total spot count: 63 32
SSN: 173 112

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2002.01 226.6 114.1 113.5 (-1.1)
2002.02 205.0 107.4 114.6 (+1.2)
2002.03 179.5 98.4 113.3 (-1.3)
2002.04 189.8 120.7 110.5 (-2.9)
2002.05 178.4 120.8 108.8 (-1.7)
2002.06 148.7 88.3 106.2 (-2.6)
2002.07 173.5 99.6 (102.1 predicted, -4.1)
2002.08 183.6 116.4 (98.5 predicted, -3.6)
2002.09 175.8 109.6 (95.5 predicted, -3.0)
2002.10 167.0 97.5 (92.0 predicted, -3.5)
2002.11 168.7 95.0 (86.7 predicted, -5.3)
2002.12 157.2 81.6 (82.4 predicted, -4.3)
2003.01 158.4 (1) 78.0 (2) (79.4 predicted, -3.0)

1) Running average based on the daily 20:00 UT observed solar flux value at 2800 MHz.
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.


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