Solar Terrestrial Activity Report [Image] Last update March 20, 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 19. Solar wind speed ranged between 339 and 396 km/sec. Solar flare activity was moderate. Solar flux was 208.2, the planetary A index was 8 (3-hour K indices: 2222 2332, Boulder K indices: 2332 2321). Region 8906 was mostly unchanged and could produce further M flares before departing the visible disk early on March 21. Region 8909 was quiet and stable. Region 8910 developed further and still has two separate magnetic deltas. Major flares are possible. Region 8913 developed at a moderate pace and could produce minor M class flares. Region 8915 was quiet and stable. Region 8916 developed slowly and could generate minor M class flares. Region 8917 is developing quickly and is a possible site for M class flare activity. The region has a weak magnetic delta. New region 8918 emerged in the northwest quadrant and is developing quickly. New region 8919 emerged near the southeast limb. It appears to be spotless early on March 20. Flares and CMEs A total of 6 C flares and 1 M flare were recorded on March 19. Region 8906 produced a C2.2 flare at 11:07, a C2.9 flare at 14:19 and an M1.6/1F flare at 17:56 UTC. Region 8910 was the source of a C2.7 flare at 09:17, a C5.3 flare at 11:48 and a long duration C9 event at 17:08 UTC. The region was also the likely source of a long duration C4 event towards the end of the day. No analysis of CME activity was possible as LASCO C2 movies have not been updated since March 17. The background x-ray flux is at the class C1-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 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 20-21. 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 8906 20000308 7 S17W75 0370 DKO beta-gamma-delta 8908 20000309 S23W57 plage 8909 20000311 6 S29W25 0010 BXO 8910 20000312 48 N12W23 0590 EKC beta-gamma-delta 8912 20000314 N15W67 plage 8913 20000314 21 S16E04 0220 EAI 8914 20000316 N16W34 plage 8915 20000316 2 N23E36 0170 HSX 8916 20000317 11 N14E53 0260 DAO 8917 20000318 14 N19E04 0070 DAO beta-delta 8918 20000319 6 N32W14 0030 CRO 8919 20000319 3 S22E58 0000 BXO Total number of sunspots: 118 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 2000.03 203.9 (1) 113.1 (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]