Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 16, 2000 at 02:45 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] [Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet to active on February 15. Solar wind speed ranged between 461 and 572 km/sec, gradually decreasing all day. Solar flare activity was low. Solar flux was 156.0, the planetary A index was 9 (3-hour Kp indices: 3421 2232, Boulder K indices: 3321 1223). Region 8856 rotated off the visible disk early today. Region 8858 developed slowly and could produce a few C flares before departing the visible disk on Feb.17. Region 8862 was quiet and stable. Region 8867 developed slowly and was mostly quiet. Region 8868 decayed further and was quiet. Region 8869 was quiet and stable, as was region 8870. Region 8871 decayed quickly and was quiet. Region 8872 decayed slowly and was quiet. Region 8873 decayed into spotless plage. Region 8874 developed slowly and was quiet. New region 8875 rotated into view at the southeast limb. New region 8876 emerged near the southeast limb. (It should be noted that over the past few months sunspot regions in the southern hemisphere have been outnumbering regions in the northern hemisphere. It is fairly common, as it has been with solar cycle 23, that northern hemisphere sunspot groups are dominant until near the sunspot maximum. At that phase of the solar cycle development and well into the decaying phase southern hemisphere sunspot groups often dominate.) Flares and CMEs One C flare was observed on February 15. Region 8867 produced a C2.1 flare at 18:55 UTC. The background x-ray flux is at the class B4 level. Coronal holes A coronal hole in the northern hemisphere was in a possibly geoeffective position on February 13-14 and could cause unsettled to active intervals on Feb.16-17. The coronal hole may, however, be located just too far to the north to be geoeffective. Forecast The geomagnetic field is expected to be quiet to unsettled on Feb.16, possibly with active intervals towards the end of the day should a coronal stream arrive. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally poor to 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 8856 20000202 1 S16W89 0020 HAX 8858 20000203 3 N25W72 0040 CSO 8862 20000206 1 S06W46 0120 HSX 8863 20000208 S16W22 plage 8865 20000208 S12W69 plage 8866 20000208 N15W27 plage 8867 20000209 11 S16W47 0070 CAO 8868 20000209 1 S25W49 0020 HSX 8869 20000210 4 S23E06 0020 CSO 8870 20000210 1 N19E13 0060 HSX 8871 20000211 2 S15W62 0020 HSX 8872 20000211 6 S28E28 0030 CSO 8873 20000213 S18E41 plage 8874 20000214 4 S09E40 0030 DSO 8875 20000215 1 S23E55 0010 HRX 8876 20000215 3 S13E62 0000 BXO Total number of sunspots: 38 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.01 140.6 62.0 82.6 (+4.7) 1999.02 141.9 66.3 84.6 (+2.0) 1999.03 126.3 68.8 83.8 (-0.8) 1999.04 117.2 63.7 85.4 (+1.6) 1999.05 148.4 106.4 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 2000.02 165.8 (1) 81.6 (2) 1) Running average based on the daily 20:00 UTC solar flux measurement at 2800 MHz by DRAO. 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]