Solar Terrestrial Activity Report [Image] Last update March 21, 2002 at 05:35 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update March 4, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 4, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 4, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet to active on March 20. Solar wind speed ranged between 347 and 609 km/sec. A solar wind shock was observed at SOHO at 13:06 UTC with a subsequent increase in solar wind speed to above 600 km/sec. Initially the interplanetary magnetic field swung southwards, but the disturbance quickly weakened and was over by the end of the day. Solar flare activity was low. Solar flux was 187.8, the planetary A index was 7 (3-hour K indices: 1101 3432, Boulder K indices: 1001 2420). Region 9866 decayed further and will soon be rotating over the southwest limb. Region 9870 decayed slowly and quietly. Region 9871 was mostly unchanged and quiet. C flares and an isolated minor M class flare are possible. Region 9873 decayed slowly and quietly. Region 9874 decayed slowly and could soon become spotless. Region 9875 developed at a moderate pace. The positive and negative magnetic polarity areas have separated quite a bit over the last day, and the region will likely become less active and decay unless new flux emerges. New region 9876 rotated into view at the southeast limb. New region 9877 emerged in the northwest quadrant. New region 9878 rotated into view at the northeast limb. Flares and CMEs A total of 6 C class events were recorded on March 20. Region 9875 produced a C1.9 flare at 08:33 UTC. The remainder of the flares were optically uncorrelated. A full halo CME was observed in LASCO C3 images beginning at 18:42 UTC. This may have been associated with a long duration C4.0 event which peaked at 18:08 UTC. The source of this event is uncertain, however, LASCO EIT difference movies point to region 9871 as the possible source of this event. If this was the origin of the CME it is likely that it will reach the Earth on March 23. It should be noted that the CME was fairly faint and there is a possibility that it had a backside origin. March 19: Region 9866 produced a long duration M1.0/1F event peaking at 11:44 UTC. This event was accompanied by a partial halo CME which could cause unsettled conditions on March 22-23 when it is expected to reach the Earth. The background x-ray flux is at the class B9 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on March 21-22. These conditions are likely to extend into most of March 23 as well. If the halo CME observed on March 20 is geoeffective a disturbance is likely to start late in the day resulting in unsettled to minor storm conditions. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [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) Solar Date Actual no. Location at region numbered sunspots midnight Area Classification Comment 9865 2002.03.08 N13W89 plage 9866 2002.03.08 5 S08W73 0270 EAO beta-gamma 9868 2002.03.11 N20W84 plage 9869 2002.03.11 N23W65 plage 9870 2002.03.11 6 S21W61 0080 CSO 9871 2002.03.13 14 S19W19 0240 EAO 9872 2002.03.15 S32W56 plage 9873 2002.03.17 5 S17W49 0050 DAO 9874 2002.03.19 9 N18E08 0030 CSO 9875 2002.03.19 6 S18E48 0140 DAO 9876 2002.03.20 3 S16E65 0050 CAO 9877 2002.03.20 2 N18W29 0030 CSO 9878 2002.03.20 1 N08E75 0060 HSX Total number of sunspots: 51 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.01 166.6 95.6 108.7 (-3.3) 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 107.6 (+2.8) 2001.05 147.1 96.6 108.7 (+1.1) 2001.06 173.0 134.0 109.8 (+1.1) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 (113.7 predicted, +0.1) 2001.10 207.6 125.6 (111.7 predicted, -2.0) 2001.11 210.6 106.5 (110.2 predicted, -1.5) 2001.12 235.1 131.8 (106.9 predicted, -3.3) 2002.01 226.6 113.9 (103.3 predicted, -3.6) 2002.02 205.0 108.0 (101.9 predicted, -1.4) 2002.03 180.9 (1) 94.3 (2) (97.6 predicted, -4.3) 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 25-45% 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. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]