Solar Terrestrial Activity ReportSolar Terrestrial Activity Report

Last update February 26, 2002 at 04:55 UTC.
[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 
2002)]
[Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 
2002)]
Recent development
The geomagnetic field was quiet to unsettled on February 25. Solar wind speed 
ranged between 312 and 359 km/sec.
Solar flare activity was moderate. Solar flux was 210.6, the planetary A index 
was 7 (3-hour K indices: 1022 3322, Boulder K indices: 2122 2323). Region 9830 
decayed further and is rotating over the southwest limb. Region 9837 decayed and 
was quiet. Region 9839 was mostly unchanged and quiet. Region 9840 was spotless 
all day in all available images, but not so according to SEC/NOAA who managed to 
observe two spots. Region 9841 decayed further and was quiet. Region 9842 
developed slowly and quietly. Region 9843 decayed early in the day and was 
spotless, then began to develop again. Region 9844 developed further and is 
capable of minor M class flaring. Region 9845 developed slowly and quietly. 
Region 9846 developed further, was quite active and could produce minor M class 
flares. Region 9847 developed slowly and quietly. New region 9848 emerged in the 
southeast quadrant. New region 9849 rotated into view at the northeast limb.

Flares and CMEs
A total of 13 C and 1 M class events were recorded on February 25. Region 9830 
produced an M1.0 flare at 02:57, a C2.4 flare at 07:17, a C3.3 flare at 15:54, a 
C3.2 flare at 19:46, a C4.1 flare at 21:"7 and a C2.0 flare at 22:54 UTC. Region 
9846 generated a C3.5 flare at 10:41, a C2.7 flare at 12:05, a C3.0 flare at 
16:19, a C2.3 flare at 22:22 and a C3.0 flare at 23:35 UTC.
The background x-ray flux is at the class C1 level.

Coronal holes
No obvious coronal holes are currently approaching geoeffective positions.

Forecast
The geomagnetic field is expected to be quiet to unsettled on February 26-28. 
Long distance medium wave (AM) band propagation along east-west paths over high 
and upper middle latitudes is fair to good.
      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
      98292002.02.14 S06W66  plage
      98302002.02.1415S18W790310EAIbeta-gamma
      98322002.02.18 S15W68  plage
      98342002.02.19 N03W26  plage
      98372002.02.206N09E030040DAO 
      98382002.02.21 N05W71  plage
      98392002.02.2116S17W480130DAI
      98402002.02.212S11E200010HSXactually spotless
      98412002.02.225S21W600030DSO 
      98422002.02.2216S19W360090DAO 
      98432002.02.224S26E180020CSO 
      98442002.02.2318N22E050130DAI 
      98452002.02.234N17E470080DAO 
      98462002.02.2410S04W530090DAO 
      98472002.02.246S14E370060DAO 
      98482002.02.254S20E330020CSO 
      98492002.02.251N23E690000AXX 
      Total number of sunspots:107 

Monthly solar data
      MonthAverage solar fluxInternational sunspot numberSmoothed sunspot number
      2000.04184.2125.5120.8
      cycle 23 sunspot max. 
      2000.07202.3170.1119.8
      2000.12173.6104.4112.0 (-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)
      2001.07131.382.2111.7 (+1.9)
      2001.08162.9106.8(113.5 predicted, +1.8)
      2001.09233.2 150.7(113.3 predicted, -0.2)
      2001.10207.6125.6(111.0 predicted, -2.3)
      2001.11210.6106.5(109.6 predicted, -1.4)
      2001.12235.1131.8(106.2 predicted, -3.4)
      2002.01226.6113.9(102.6 predicted, -3.6)
      2002.02205.2 (1)173.0 (2)(101.2 predicted, -1.4)

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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