Solar Terrestrial Activity Report [Image] Last update February 25, 2000 at 03:20 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update February 3, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 3, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 3, 2000)] [Historical solar and geomagnetic data charts 1954-1999] Recent development The geomagnetic field was quiet to minor storm on February 24. Solar wind speed ranged between 517 and 746 km/sec under the influence of a high speed coronal stream. Solar flare activity was moderate. Solar flux was 192.2, the planetary A index was 26 (3-hour K indices: 2445 4444, Boulder K indices: 2444 5534). Region 8875 decayed slowly and was quiet. The region will rotate off the visible disk on Feb.26. Region 8879 was mostly unchanged and could produce C flares and possibly a minor M flare. Region 8881 did not change significantly and was quiet. Region 8882 developed further and could produce a major flare. Region 8883 developed slowly and could be capable of generating a minor M flare. Region 8885 was quiet and stable, as was region 8886. New region 8887 emerged in the southeast quadrant. New region 8888 rotated into view at the northeast limb. New region 8889 rotated partly into view at the northeast limb, magnetograms suggests that this is a complex region (or three smaller regions stacked almost on top of each other). The region could be capable of major flaring. New region 8890 emerged near the southeast limb. An active and large region is rotating into view at the southeast limb, this region could be capable of producing major flares. Another active region is about to rotate into view at the northeast limb at a low latitude. Flares and CMEs 8 C flares and 1 M flare were recorded on February 24. Region 8889 produced an M1.1 flare at 01:11 UTC. The background x-ray flux is at the class C1 level. Coronal holes A trans equatorial coronal hole was in a geoeffective position on February 21-25. This coronal hole is somewhat smaller than it has been over the last several months and is probably decaying. Forecast The geomagnetic field is expected to be unsettled to minor storm on February 25 while quiet to active is likely on February 26-27. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very 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 8872 S31W86 plage 8874 S09W78 plage 8875 10 S23W68 0060 DAO 8876 S11W56 plage 8877 S22W66 plage 8879 20000217 6 N22W14 0260 CHO 8881 20000221 6 N19E11 0050 DAO 8882 20000221 19 S15E34 0500 DKI 8883 20000222 14 N13E34 0140 DSO 8885 20000223 3 N12W55 0020 BXO 8886 20000223 5 S14E18 0010 BXO 8887 20000224 4 S10E46 0030 DSO 8888 20000224 1 N36E56 0040 HSX 8889 20000224 2 N20E67 0180 ESO beta-gamma 8890 20000224 1 S11E65 0000 AXX Total number of sunspots: 71 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.01 140.6 62.4 82.6 (+4.8) 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 (97.4 predicted, + 3.0) 1999.09 135.7 70.9 (102.4 predicted, +5.0) 1999.10 164.8 116.4 (107.5 predicted, +5.1) 1999.11 191.5 132.7 1999.12 169.8 86.4 2000.01 158.1 90.2 2000.02 164.9 (1) 127.2 (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]