Solar Terrestrial Activity ReportSolar Terrestrial Activity Report

Last update January 17, 2002 at 04:10 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, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 1, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 1, 
2002)]
[Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 
2002)]
Recent development
The geomagnetic field was quiet to slightly unsettled on January 16. Solar wind 
speed ranged between 353 and 407 km/sec.
Solar flare activity was moderate. Solar flux was 216.1, the planetary A index 
was 4 (3-hour K indices: 1131 1211, Boulder K indices: 1130 2220). Region 9775 
was very active and could produce M class flares while at and just behind the 
southwest limb. Region 9778 decayed further and was quiet. Region 9779 was quiet 
and stable, as was region 9781. Region 9782 decayed slightly and lost its 
magnetic delta structure early in the day. Minor M class flares are possible. 
Region 9783 was quiet and stable. Region 9785 was generally unchanged and quiet, 
the region could be capable of producing occasional minor M class flares. New 
region 9786 emerged in the southeast quadrant.
Flares and CMEs
A total of 12 C and 1 M class events were recorded on January 16. Region 9775 
produced a C7.1 flare at 08:09, a C4.3 flare at 09:08, an M1.5 flare at 10:13, a 
C4.1 flare at 15:29 and a C4.3 flare at 16:55 UTC. Region 9773 generated a C6.2 
flare at 17:56 UTC.
The background x-ray flux is at the class C2 level.
Coronal holes
A small coronal hole in the southern hemisphere was in a geoeffective position 
on January 16.
Forecast
The geomagnetic field is expected to be quiet to unsettled on January 18-19. A 
coronal stream could begin to influence the field on January 19 and cause a few 
unsettled to active intervals. Long distance medium wave (AM) band propagation 
along east-west paths over high and upper middle latitudes is poor to fair.
      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.
Active solar regions (Recent map)
      Solar regionDate numberedActual no. sunspotsLocation at 
      midnightAreaClassificationComment
      97752002.01.076S06W860160EAObeta-gamma-delta
      97762002.01.07 N08W63  plage
      97772002.01.08 S06W40  plage
      97782002.01.089S14W350040DAO 
      97792002.01.082N29W380110HSX
      97812002.01.112S05W010080HAX
      97822002.01.1116N06E050260DAO 
      97832002.01.126S12E250170CAO
      97842002.01.13 S28E18  plage
      97852002.01.137N10E140180DAO
      97862002.01.163S26E070030DSO
      Total number of sunspots:51 

Monthly solar data
      MonthAverage solar fluxInternational sunspot numberSmoothed sunspot number
      2000.04184.2125.5120.8
      cycle 23 sunspot max. 
      2000.07202.3170.1119.8
      2000.11178.8106.8112.7 (-1.8)
      2000.12173.6104.4112.0 (-0.7)
      2001.01166.695.6108.7 (-3.3)
      2001.02146.680.6104.1 (-4.6)
      2001.03177.7113.5104.8 (+0.7)
      2001.04177.7107.7107.6 (+2.8)
      2001.05147.196.6108.7 (+1.1)
      2001.06173.0134.0109.8 (+1.1)
      2001.07131.382.2(111.2 predicted, +1.4)
      2001.08162.9106.8(111.7 predicted, +0.5)
      2001.09233.2 150.7(110.7 predicted, -1.0)
      2001.10207.6125.6(108.0 predicted, -2.7)
      2001.11210.6106.5(106.3 predicted, -1.7)
      2001.12235.1131.8(103.0 predicted, -3.3)
      2002.01219.9 (1)94.5 (2)(99.4 predicted, -3.6)

1) Running average based on the daily 20:00 UT 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 25-40% 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. Comments and suggestions are always welcome.


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