Solar Terrestrial Activity Report [Image] Last update February 22, 2000 at 03:05 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 active on February 21. Solar wind speed ranged between 383 and 468 km/sec. Although the interplanetary magnetic field was strong all day, it was, with a few exceptions, northwards. This resulted in a much weaker geomagnetic disturbance than was expected. Solar flare activity was moderate. Solar flux was 152.1, the planetary A index was 15 (3-hour K indices: 3432 3432, Boulder K indices: 3432 3533). Region 8869 developed further and is capable of producing a major flare, the region will rotate over the west limb on Feb.22. Region 8870 was quiet and stable. Region 8872 decayed into spotless plage. Region 8875 developed further and was quiet. The region could produce minor M flares. Region 8876 decayed into spotless plage. Region 8879 was quiet and stable. Region 8880 was quiet and stable and will rotate off the visible disk today. New region 8881 emerged near the northeast limb. New region 8882 rotated partly into view at the southeast limb, this region is capable of minor M class flaring. Further active regions at the northeast and southeast limbs will rotate into view over the next few days. Flares and CMEs 5 C flares and 2 M flares were recorded on February 21. Region 8869 produced a C3.0 flare at 00:44 UTC, a C2.1 flare at 17:08 UTC and an M1.2/2B flare at 23:18 UTC. Region 8882 continued to be active and was the source of an M1.8 flare at at 08:36 UTC. The background x-ray flux is at the class B6 level. Coronal holes A trans equatorial coronal hole will rotate into a geoeffective position on February 21-25 and start a geomagnetic disturbance on Feb.24. This coronal hole is smaller than it has been over the last several months and is probably decaying. Forecast The geomagnetic field is expected to be quiet to active on February 23. A coronal stream will cause unsettled to minor storm conditions on February 24-26. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 8869 32 S19W74 0520 FAI beta-gamma 8870 1 N20W65 0040 HSX 8872 S31W47 plage 8874 S09W39 plage 8875 12 S22W27 0150 CAO 8876 S11W17 plage 8877 S22W29 plage 8879 20000217 1 N22E25 0240 HSX 8880 20000220 2 S06W81 0010 BXO 8881 20000221 3 N19E53 0010 BXO 8882 20000221 1 S16E70 0050 HSX Total number of sunspots: 52 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 2000.02 162.3 (1) 111.2 (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]