Solar Terrestrial Activity Report [Image] Last update March 25, 2000 at 05:30 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 24. Solar wind speed ranged between 507 and 763 km/sec under the influence of a high speed coronal stream. Solar flare activity was high. Solar flux was 218.9, the planetary A index was 10 (3-hour K indices: 2212 4322, Boulder K indices: 2212 4312). Region 8910 is rotating over the west limb and could still produce another major flare while at or just behind the west limb. Region 8913 decayed further and was quiet. Region 8915 was quiet and stable. Region 8916 decayed slowly and was quiet. Region 8917 decayed slowly and was mostly quiet. Region 8918 is rotating over the west limb and has been quiet. Region 8920 decayed into spotless plage. Region 8921 developed slowly has M class flare potential. Regions 8922 and 8923 were quiet and stable, as were regions 8924 and 8925. Region 8926 developed further and could be capable of C class flaring. Region 8927 was mostly unchanged and quiet. New region 8928 rotated into view at the northeast limb and may be capable of producing another minor M flare. Flares and CMEs A total of 5 C flares, 2 M flares and 1 X flare were recorded on March 24. Region 8910 produced an X1.8/2B flare at 07:52 UTC. Moderately strong type II and IV sweeps were observed as well, the associated CME will not reach Earth. Region 8910 generated an M2.6 impulsive flare at 15:22 UTC. Region 8928 was the source of an impulsive M2.8 flare at 11:29 UTC. None of the C class flares were optically assigned to any region. The background x-ray flux is at the class C2 level. Coronal holes The large coronal hole that has been around for several months has split into three smaller coronal holes. One is in the northern hemisphere and was in a geoeffective position on March 19, another (fairly small and closing because of development in region 8913) is in the southern hemisphere and was in a geoeffective position on March 20. The third, and largest remaining part, is trans equatorial and was in a geoeffective position on March 21-22. Forecast The geomagnetic field is expected to be quiet to active on March 25 due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 8910 20000312 1 N13W84 0080 HSX 8913 20000314 8 S15W64 0100 EAO 8915 20000316 1 N23W27 0170 HSX 8916 20000317 10 N12W14 0140 DAO 8917 20000318 10 N20W61 0160 DAO 8918 20000319 3 N32W76 0190 CSO 8919 20000319 S21W09 plage 8920 20000320 N24E03 plage 8921 20000320 26 S17E23 0420 EKC 8922 20000321 1 N12E17 0000 AXX 8923 20000322 2 S26E18 0020 CAO 8924 20000323 4 N12E55 0140 CSO 8925 20000323 2 S17E63 0090 CAO 8926 20000323 11 S10W31 0090 DAI 8927 20000323 9 N17W14 0060 DSO 8928 20000324 2 N19E60 0060 CSO Total number of sunspots: 90 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 2000.03 208.0 (1) 148.9 (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]