Solar Terrestrial Activity Report [Image] Last update May 12, 2002 at 04:25 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update May 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to major storm on May 11. Solar wind speed ranged between 338 and 482 km/sec. A moderately strong solar wind shock was observed at SOHO at 09:16 UTC. Solar wind speed jumped from 360 to 450 km/sec and the interplanetary magnetic field immediately swung moderately to strongly southwards. Later on the IMF was at times very strongly southwards causing major geomagnetic storming with some high latitude stations reporting severe storming. The source of the disturbance is likely a faint full halo CME observed in connection with a long duration C4 event in region 9934 on May 8. Although the disturbance was expected it was stronger than predicted. Solar flare activity was moderate. Solar flux was 188.0, the planetary A index was 40 (3-hour K indices: 2136 6654, Boulder K indices: 1135 6644). Region 9932 decayed and was spotless by late afternoon. Region 9933 was quiet and stable. Region 9934A (the northern part of region 9934) was quiet and stable, no significant changes were noted in or near the huge penumbra. Region 9934B (the southern part of region 9934) developed further in the trailing spots section (which has at least two magnetic delta structures) while some decay was observed in the intermediate and leader spots. Region 9937 decayed quickly after producing a minor M class flare. Another minor M class flare is still possible, however, the magnetic delta structure observed yesterday has disappeared. Region 9938 decayed and could become spotless early today. After many days of failing to observe regions 9939/9940 as a single region, SEC/NOAA finally deleted region 9939. Region 9940 decayed further and was quiet. Region 9943 was quiet and stable. Region 9945 developed several new spots and the huge penumbra split into two. The region was mostly quiet but is capable of M class flaring. Region 9946 developed slowly and quietly. Region 9947 decayed and was spotless by the end of the day. Region 9948 was quiet and displayed no significant changes. New region 9949 emerged near the central meridian and rotated into the southwest quadrant. New region 9950 emerged quickly in the southeast quadrant. Flares and CMEs A total of 10 C and 1 M class events were recorded on May 11. Region 9937 produced an M1.4 flare at 11:32 UTC. This event was associated with a moderate type II radio sweep and a CME observed off the west limbs. Region 9950 generated a C2.7 flare at 16:50 UTC. Region 9934 was the source of a C3.7 flare at 17:38 UTC. The background x-ray flux is at the class B7 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on May 12 and quiet to unsettled on May 13-14. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 Location region numbered no. at Area Classification Comment sunspots midnight 9927 2002.04.29 S23W73 plage 9928 2002.04.29 N19W84 plage 9932 2002.05.01 1 S27W67 0020 AXX now spotless 9933 2002.05.01 1 N18W67 0090 HAX 9934 2002.05.01 27 S17W59 1060 FKO two separate regions beta-gamma-delta 9936 2002.05.02 S16W80 plage 9937 2002.05.03 18 S09W38 0240 DAI 9938 2002.05.03 1 S05W34 0010 HSX 9940 2002.05.04 7 N17W24 0030 ESO 9941 2002.05.05 S22W71 plage 9942 2002.05.05 N21W42 plage 9943 2002.05.05 1 S10W16 0000 AXX 9944 2002.05.07 N08W17 plage 9945 2002.05.07 9 S04E14 0310 DKO 9946 2002.05.08 16 S06E25 0060 DAO 9947 2002.05.10 1 N23W59 0020 AXX now spotless 9948 2002.05.10 6 S21E61 0420 EKO 9949 2002.05.11 3 S16W06 0010 HSX 9950 2002.05.11 5 S06E44 0030 BXO Total number of sunspots: 96 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 2001.04 177.7 107.7 107.5 (+2.7) 2001.05 147.1 96.6 108.6 (+1.1) 2001.06 173.0 134.0 109.8 (+1.2) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 (114.7 predicted, +0.7) 2001.12 235.1 132.2 (112.5 predicted, -2.2) 2002.01 226.6 113.9 (109.8 predicted, -2.7) 2002.02 205.0 108.0 (108.4 predicted, -1.4) 2002.03 179.5 98.1 (104.2 predicted, -4.2) 2002.04 189.8 120.4 (98.3 predicted, -3.9) 2002.05 183.0 (1) 83.5 (2) (93.8 predicted, -4.5) 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]