Solar Terrestrial Activity Report [Image] Last update March 26, 2000 at 05:10 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 unsettled on March 25. Solar wind speed ranged between 530 and 747 km/sec under the influence of a high speed coronal stream. Solar flare activity was low. Solar flux was 205.1, the planetary A index was 8 (3-hour K indices: 2222 1331, Boulder K indices: 2222 2331). Region 8913 decayed further and was quiet, the region is rotating over the west limb. Region 8915 was quiet and stable. Region 8916 decayed slowly and was quiet. Region 8917 decayed slowly and was quiet, the region will rotate off the visible disk early on March 27. Region 8921 was mostly unchanged and has minor M class flare potential. Region 8922 decayed into spotless plage. Regions 8923, 8924 and 8925 were mostly quiet and stable. Region 8926 developed a magnetic delta configuration and could be capable of producing a minor M flare. Region 8927 was mostly unchanged and quiet. Region 8928 did not change significantly and is likely to produce further C flares. New regions 8929 and 8930 emerged in the southeast quadrant near region 8925. Flares and CMEs A total of 9 C flares were recorded on March 25. Region 8926 produced a C8.0 flare at 09:42, a C5.0 flare at 12:24, a C2.7 flare at 13:21 and a C2.9 flare at 22:05 UTC. Region 8928 was the source of a C3.5 flare at 19:20 UTC. Region 8921 generated the most interesting flare of the day, a C7.4/1F event at 22:43 UTC. This event was accompanied by moderately strong type II (with an estimated exit speed of 1700 km/sec) and IV sweeps and occurred almost on top of the central meridian. The associated coronal mass ejection has a fairly high chance of impacting Earth. With LASCO movies unavailable it is difficult to state when the CME will arrive and how severe the impact will be. The most likely time of arrival is sometime between late on March 27 and early on March 29. This will likely result in unsettled to minor or major storming. 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 26-27. A CME could impact Earth sometime from late on March 27 until early on the 29th and cause unsettled to major storming. 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 Location region numbered no. at Area Classification Comment sunspots midnight 8913 20000314 6 S16W78 0070 EAO 8915 20000316 2 N23W41 0130 HSX 8916 20000317 9 N12W27 0110 DSO 8917 20000318 4 N19W74 0060 DSO 8919 20000319 S21W22 plage 8920 20000320 N24W10 plage 8921 20000320 27 S18E09 0240 DAI 8922 20000321 N12E04 plage 8923 20000322 2 S26E05 0010 CAO 8924 20000323 12 N10E41 0120 DAO 8925 20000323 8 S18E50 0080 CSO 8926 20000323 19 S10W45 0080 DSO beta-gamma-delta 8927 20000323 14 N16W28 0040 CAO 8928 20000324 7 N19E45 0050 DAO 8929 20000325 1 S25E53 0000 AXX 8930 20000325 2 S36E54 0000 BXO Total number of sunspots: 113 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 2000.03 207.9 (1) 156.7 (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]