Solar Terrestrial Activity Report [Image] Last update March 28, 2000 at 03:35 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 on March 27. Solar wind speed ranged between 378 and 483 km/sec. Solar flare activity was moderate. Solar flux was 204.9, the planetary A index was 5 (3-hour K indices: 2101 2221, Boulder K indices: 2210 3311). Region 8915 was quiet and stable and will rotate over the west limb on March 29. Region 8916 was quiet and stable. Region 8921 decayed significantly and was quiet, the region could still produce a minor M flare. Region 8923 was quiet and stable. Region 8924 was mostly unchanged and should be capable of minor M class flaring. Region 8925 developed slowly and has M class flare potential. Region 8926 maintained its magnetic delta configuration could produce further minor M flares, perhaps even an isolated major flare, before it rotates over the west limb on March 29. Region 8927 decayed slowly and was quiet. Region 8928 decayed quickly retaining only a single spot. Regions 8931 and 8932 were mostly quiet and stable. New regions 8933 and 8934 emerged in the northeast quadrant. Fairly strong emissions are visible over the southeast limb as at least 2 regions prepare to rotate into view. Flares and CMEs A total of 8 C flares and 1 M flare were recorded on March 27. Region 8931 produced a C2.3 flare at 07:55 UTC. All other optically assigned flares had their origin in region 8926. This region generated a C9.6 flare at 01:15 UTC, an M1.0/1N flare at 05:18, a C6.2 flare at 10:42, a C8.4/1F flare at 14:00, a C7.9 flare at 14:19, a C8.9 flare at 15:35 and finally a C4.7 flare at 21:19 UTC. Region 8926 produced an M3.1 flare at 01:37 on March 28. March 25: Region 8921 generated the most interesting flare of the day, a C7.4/1F event at 22:43 UTC. This event occurred almost on top of the central meridian and was accompanied by a moderately strong type II sweep and a weak but very long lasting type IV sweep. The associated coronal mass ejection, which is probably a minor one, has a fairly high chance of impacting Earth. With LASCO movies unavailable at the time of the flare 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 early on March 28 and noon on March 29. This could result in unsettled to minor 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 active on March 28. A CME could impact Earth sometime from early on March 28 until noon on the 29th and cause unsettled to minor storming. 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 8915 20000316 1 N23W65 0170 HSX 8916 20000317 6 N13W56 0130 DSO 8919 20000319 S21W48 plage 8920 20000320 N24W36 plage 8921 20000320 20 S18W17 0130 DAI 8922 20000321 N12W22 plage 8923 20000322 1 S26W24 0000 AXX 8924 20000323 22 N10E13 0230 DAI 8925 20000323 20 S18E21 0270 DKI 8926 20000323 6 S09W71 0070 DSO beta-gamma-delta 8927 20000323 11 N17W52 0070 DSO 8928 20000324 1 N18E16 0040 HSX 8929 20000325 S25E27 plage 8930 20000325 S36E28 plage 8931 20000326 4 S14E34 0010 BXO 8932 20000326 1 S14E60 0060 HSX 8933 20000327 1 N16E33 0010 HRX 8934 20000327 3 N22E53 0010 BXO Total number of sunspots: 97 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 2000.03 207.8 (1) 172.3 (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]