Solar Terrestrial Activity Report [Image] Last update March 30, 2000 at 04:55 UTC. Minor update posted at 16:47 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 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 2, 2000)] [Historical solar and geomagnetic data charts 1954-1999] Recent development The geomagnetic field was quiet to active on March 29. Solar wind speed ranged between 310 and 756 km/sec. A disturbance (likely related to a CME in connection with a flare in region 8921 late on March 25) arrived at ACE at 06:36 UTC. Solar wind speed quickly increased to 400 km/sec and later on increased to above 700 km/sec. Wind speed is currently slowly decreasing to below 500 km/sec. Solar flare activity was low. Solar flux was 208.8, the planetary A index was 9 (3-hour K indices: 1012 2244, Boulder K indices: 0011 2234). Region 8916 was quiet and is rotating off the visible disk. Region 8921 decayed quickly and was quiet. Region 8924 maintained its magnetic delta configuration and could produce an M flare. Region 8925 still had a weak magnetic delta but was mostly quiet and could be decaying. Region 8926 rotated off the visible disk. Region 8927 is rotating over the west limb. Region 8928 was quiet and stable, as were regions 8931, 8932, 8933 and 8934. New region 8935 emerged quickyl in the southeast quadrant. New region 8936 rotated partly into view at the southeast limb. The region is unstable and will likely produce several C flares and perhaps a minor M flare. New region 8937 emerged near the northeast limb. Comment added at 16:47 UTC on March 30: Region 8936 produced an M3.4 flare at 16:07 UTC and an M1.3 flare at 12:45 UTC. A long duration M1.2 event was observed peaking at 07:14 UTC, this flare has not yet been optically assigned. Region 8925 has become more active as well, producing several C flares. Flares and CMEs A total of 5 C flares were recorded on March 29. Region 8936 produced a C4.4 flare at 18:47 UTC. A full halo coronal mass ejection with a backside origin was observed after 11h UTC in LASCO movies. 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 March 30. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 8916 20000317 1 N12W84 0060 HSX 8919 20000319 S21W74 plage 8920 20000320 N24W62 plage 8921 20000320 10 S17W44 0040 DSO 8922 20000321 2 N16W44 0010 AXX 8923 20000322 S26W50 plage 8924 20000323 18 N10W14 0340 EKO beta-gamma-delta 8925 20000323 27 S17W07 0180 EAI beta-gamma-delta 8927 20000323 2 N15W81 0000 BXO 8928 20000324 1 N19W12 0020 HSX 8929 20000325 S25E01 plage 8930 20000325 S36E02 plage 8931 20000326 10 S13E07 0060 DAO 8932 20000326 1 S14E31 0050 HSX 8933 20000327 4 N16E07 0030 DSO 8934 20000327 2 N22E25 0010 BXO 8935 20000329 11 S07E33 0030 CSO 8936 20000329 7 S16E71 0080 CSO 8937 20000329 2 N26E64 0000 AXX Total number of sunspots: 98 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.02 141.9 66.1 84.6 (+2.0) 1999.03 126.3 69.1 83.8 (-0.8) 1999.04 117.2 63.9 85.4 (+1.6) 1999.05 148.4 106.3 90.4 (+5.0) 1999.06 169.8 137.7 93.0 (+2.6) 1999.07 165.6 113.5 94.4 (+1.4) 1999.08 170.7 93.7 97.5 (+3.1) 1999.09 135.7 71.5 (102.6 predicted, +5.1) 1999.10 164.8 116.4 (107.7 predicted, +5.1) 1999.11 191.5 132.7 (110.2 predicted, +2.5) 1999.12 169.8 86.4 2000.01 158.1 90.2 2000.02 174.1 112.3 2000.03 207.7 (1) 187.4 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz.. 2) Unofficial, accumulated value. The official value 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]