Solar Terrestrial Activity Report [Image] Last update March 24, 2000 at 04:15 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 23. Solar wind speed ranged between 502 and 668 km/sec under the influence of a high speed coronal stream. Solar flare activity was moderate. Solar flux was 224.1, the planetary A index was 11 (3-hour K indices: 2223 3332, Boulder K indices: 2323 3422). Region 8910 was mostly unchanged and could produce further minor or major flares before rotating off the visible disk on March 25. Region 8913 decayed slowly and was mostly quiet. Region 8915 decayed slowly and was quiet. Region 8916 decayed slowly and was mostly quiet, the region has a minor chance of producing a small M flare. Region 8917 decayed slowly and has a fair chance of producing a minor M class flare. Region 8918 decayed slowly and may be capable of minor M class flaring before departing the visible disk on March 25. Region 8920 was quiet and stable. Region 8921 was mostly unchanged and has M class flare potential. Regions 8922 and 8923 were quiet and stable. New region 8924 rotated into view at the northeast limb. New region 8925 rotated into view at the southeast limb. New region 8926 emerged in the southwest quadrant. New region 8927 emerged in the northeast quadrant near the central meridian and region 8916. It has been developing quickly and produced many sub flares towards the end of the day. Should the region continue to develop quickly it will become capable of M class flaring today. Flares and CMEs A total of 9 C flares and 2 M flares were recorded on March 23. Region 8910 produced an M2.0 long duration event peaking at 12:14 UTC as well as a long duration C7.1 event at 21:54 UTC. Region 8913 was the source of a C2.8 flare at 04:26 UTC. Region 8915 generated a C5.0 flare at 06:13 UTC while region 8917 managed a C7.5 long duration event peaking at 08:21 and a C2.6 flare at 19:16 UTC. An M1.3 flare at 00:30 UTC and a C9.3 flare at 01:01 UTC were not optically assigned to any of the regions on the disk. 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 24-25 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 8909 20000311 S28W80 plage 8910 20000312 11 N13W75 0450 EAC beta-gamma 8913 20000314 12 S16W50 0130 EAO 8914 20000316 N16W86 plage 8915 20000316 1 N23W14 0140 HSX 8916 20000317 11 N13E01 0180 CAO 8917 20000318 10 N20W35 0230 DAO 8918 20000319 7 N32W66 0330 EAO 8919 20000319 S21E04 plage 8920 20000320 6 N23E16 0030 CSO 8921 20000320 17 S17E37 0340 DKI 8922 20000321 2 N14E32 0000 AXX 8923 20000322 3 S26E32 0020 CSO 8924 20000323 4 N13E70 0110 CAO 8925 20000323 1 S17E76 0030 HAX 8926 20000323 5 S10W18 0030 DAO 8927 20000323 6 N18E00 0040 DAO Total number of sunspots: 96 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 2000.03 207.5 (1) 141.5 (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]