Solar Terrestrial Activity Report [Image] Last update March 19, 2000 at 06:15 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 18. Solar wind speed ranged between 304 and 397 km/sec. A minor disturbance has been in progress since early on March 19. Solar flare activity was moderate. Solar flux was 194.8, the planetary A index was 7 (3-hour K indices: 1012 2332, Boulder K indices: 1011 2322). Region 8906 lost several spots and some of its areal coverage, however, a magnetic delta developed and the region was quite active towards the end of the day. Further M class flares are possible. Region 8909 was mostly quiet and stable. Region 8910 developed further and is now very complex with two separate magnetic deltas. Major flares are possible in this region. Region 8913 was quiet and stable, C class flares are possible. Region 8915 developed slowly and could produce C flares. Region 8916 has M class flaring potential and is developing slowly. New region 8917 emerged in the northeast quadrant and is developing quickly. An active and interesting region at the southeast limb should rotate into view today. Flares and CMEs A totoal of 4 C flares and 3 M flares were recorded on March 18. Region 8906 produced an M2.1/1N flare at 21:02 UTC, it was accompanied by a moderately strong type II sweep. Region 8906 was also the source of an M3.9/1N long duration event peaking at 23:57 UTC. Region 8909 generated a C4.5/1F long duration event peaking at 21:54 UTC, it was accompanied by a weak type II sweep. Region 8910 was the source of a long duration M2.6/2N event peaking at 23:33 UTC. A large coronal mass ejection was observed off the southeast limb just after midnight. An impressive post flare loop system was visible above the southeast limb several hours after the flare. The originating flare may actually have been one of the M flares mentioned above, perhaps the M3.9 flare. The background x-ray flux is at the class C1 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 will rotate into a geoeffective position on March 19, another (and fairly small one) is in the southern hemisphere and could rotate into a geoeffective position on March 20. The third, and largest remaining part, is trans equatorial and should rotate into a geoeffective position on March 21-22. Forecast The geomagnetic field is expected to be quiet to unsettled on March 19-20. A coronal hole related disturbance is likely to start on March 22 and could cause unsettled to active intervals until March 25. 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 8902 20000306 S17W82 plage 8906 20000308 10 S17W62 0410 DKO beta-gamma-delta 8908 20000309 S23W44 plage 8909 20000311 4 S28W16 0030 DRO 8910 20000312 35 N11W10 0390 DAI beta-gamma-delta 8912 20000314 N15W54 plage 8913 20000314 12 S16E17 0140 DAO 8914 20000316 N16W21 plage 8915 20000316 3 N23E49 0170 CSO 8916 20000317 6 N13E64 0280 CSO 8917 20000318 2 N20E18 0010 BXO Total number of sunspots: 72 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 2000.03 203.6 (1) 106.4 (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]