Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 1, 2000 at 06:00 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update January 1, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update January 1, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 1, 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 unsettled on January 31. Solar wind speed ranged between 528 and 663 km/sec under the influence of a high speed coronal stream. Solar flare activity was low. Solar flux was 138.6, the planetary A index was 8 (3-hour Kp indices: 3222 3322, Boulder K indices: 2222 3221). Region 8841 changed little and could produce further C flares. Region 8845 was quiet and stable. Region 8847 rotated off the visible disk. Region 8848 could produce occasional C flares. Region 8849 decayed into spotless plage. Region 8850 was quiet and stable. Region 8851 has been developing fairly quickly and could soon become capable of minor M class flaring. New region 8852 emerged quickly in the northeast quadrant. Several active regions are approaching the east limb (both northeast and southeast limbs) and should rotate into view within 2-3 days. Flares and CMEs 6 C flares were observed on January 31. Region 8841 produced a C1.7 flare at 0157 UTC and a C1.3 flare at 02:42 UTC. Region 8851 was the source of a C1.0 flare at 11:01 UTC. The background x-ray flux is at the class B5 level. Coronal holes A trans equatorial coronal hole will likely rotate into a geoeffective position on February 4. Forecast The geomagnetic field is expected to be quiet to active February 1-3. 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 8841 20000121 4 S301W61 0080 DAO 8845 20000125 1 S16W61 0010 HRX 8846 20000126 N37W14 plage 8848 20000126 4 S09E13 0070 CSO 8849 20000128 S17W19 0010 BXO 8850 20000130 2 S17E11 0010 BXO 8851 20000130 6 N27E29 0070 DAO 8852 20000131 5 N10E14 0020 CRO Total number of sunspots: 22 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1998.12 150.1 81.9 77.9 (+4.9) 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 (94.8 predicted, +1.8) 1999.08 170.7 93.7 (99.4 predicted, +4.6) 1999.09 135.7 70.6 (105.7 predicted, +6.3) 1999.10 164.8 116.4 1999.11 191.5 132.7 1999.12 169.8 86.4 2000.01 158.1 (1) 140.9 (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]