Solar Terrestrial Activity Report [Image] Last update March 20, 2002 at 05:30 UTC. Minor update added at 13:49 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 minor storm on March 19. Solar wind speed ranged between 349 and 452 km/sec. Solar flare activity was moderate. Solar flux was 174.8, the planetary A index was 17 (3-hour K indices: 5533 1232, Boulder K indices: 5432 3222). Region 9864 decayed and was spotless by noon. Region 9866 continued its slow decay and has now only a minor chance of producing further M class flares. Region 9870 decayed slowly and quietly. Region 9871 decayed as well and could produce C flares and perhaps an isolated minor M class flare. Region 9872 decayed into spotless plage. Region 9873 decayed substantially and had lost most of its trailing spots by the end of the day. New region 9874 emerged quickly early in the day, then decayed almost as quickly and could become spotless today. New region 9875 rotated into view at the southeast limb. SEC/NOAA failed to number another spotted region near the southeast limb. A fairly active region is at the northeast limb and could rotate into view today or tomorrow. Comment added at 13:49 UTC on March 20: A solar wind shock was observed at SOHO at 13:06 UTC. Solar wind speed increased to near 600 km/sec following this shock and the interplanetary magnetic field swung moderately southwards. This will likely result in the geomagnetic field becoming active and there is a chance of minor storm intervals later today and early tomorrow. Otherwise region 9875 has been fairly active and is becoming capable of producing minor M class flares. Flares and CMEs A total of 2 C and 1 M class events were recorded on March 19. Region 9866 produced a C1.8 flare at 01:29 and a long duration M1.0/1F event peaking at 11:44 UTC. The latter 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. March 18: A long duration M1.0 event peaked at 02:31 UTC. A full halo CME was observed shortly afterwards in LASCO images. The source of this event was a large filament eruption near region 9870 and extending into region 9866. The CME will likely reach the Earth sometime on March 20 and cause unsettled to minor storm conditions. The background x-ray flux is at the class B5 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to minor storm on March 20-21. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very 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 9864 2002.03.07 1 N18W84 0020 HSX 9865 2002.03.08 N13W76 plage 9866 2002.03.08 10 S09W59 0290 EAI beta-gamma 9867 2002.03.11 S31W87 plage 9868 2002.03.11 N20W71 plage 9869 2002.03.11 N23W65 plage 9870 2002.03.11 8 S20W47 0080 CAO 9871 2002.03.13 14 S19W06 0260 EAO 9872 2002.03.15 S32W43 plage 9873 2002.03.17 12 S18W35 0090 DAO 9874 2002.03.19 3 N17E21 0020 CSO 9875 2002.03.19 1 S19E62 0010 HSX Total number of sunspots: 49 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) 2002.03 180.5 (1) 89.7 (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]