Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 17, 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 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 on February 16. Solar wind speed ranged between 378 and 475 km/sec. Solar flare activity was low. Solar flux was 160.2, the planetary A index was 5 (3-hour Kp indices: 2201 2220, Boulder K indices: 2311 2222). Region 8858 will be rotating over the west limb today. Region 8862 was quiet and stable. Region 8867 developed slowly and could produce further C flares. Region 8868 was quiet and stable. Region 8869 developed slowly and could produce C flares. Region 8870 was quiet and stable. Region 8871 decayed further and will likely become spotless before rotating off the visible disk on Feb.18. Regions 8872 and 8874 decayed slowly and were quiet. Region 8875 was quiet and stable. Region 8876 developed slowly and could produce C flares. New region 8877 emerged in the southeast quadrant. New region 8878 emerged in the southwest quadrant. Flares and CMEs 4 C flares were observed on February 16. Region 8867 produced both optically correlated events, a C1.3 flare at 08:48 UTC and a C2.4 flare at 20:32 UTC. The background x-ray flux is at the class B6 level. Coronal holes No coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on Feb.17. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 8858 20000203 2 N27W79 0100 DAO 8862 20000206 1 S06W59 0130 HSX 8863 20000208 S16W35 plage 8865 20000208 S12W82 plage 8866 20000208 N15W40 plage 8867 20000209 10 S16W60 0110 DAO 8868 20000209 1 S24W61 0020 HRX 8869 20000210 13 S23W08 0090 DSO 8870 20000210 1 N19E00 0090 HSX 8871 20000211 2 S14W74 0000 BXO 8872 20000211 4 S28E16 0020 CRO 8873 20000213 S18E28 plage 8874 20000214 2 S08E27 0020 BXO 8875 20000215 4 S22E40 0020 BXO 8876 20000215 7 S13E48 0050 CSO 8877 20000216 1 S26E28 0010 HRX 8878 20000216 4 S27W42 0030 CRO Total number of sunspots: 52 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 2000.02 165.5 (1) 87.8 (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]