Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update January 28, 2000 at 04:40 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 active on January 27 with minor storming observed at high latitude stations. Solar wind speed ranged between 337 and 666 km/sec. A solar wind shock was observed at 13:53 at ACE. Soon afterwards the interplanetary magnetic field became much stronger and was at times very strongly southwards. Solar wind density values nearly reached 100 particles/cm3, an extremely high level which is rarely observed. The source of the disturbance is mainly a recurrent coronal hole, however, it may have pushed a small coronal mass ejection ahead of the coronal stream. Solar flare activity was very low. Solar flux was 132.4, the planetary A index was 12 (3-hour Kp indices: 2223 3344, Boulder K indices: 3222 3343). Region 8840 was quiet and stable, the region is spotless early on Jan.28. Region 8841 was mostly unchanged and quiet. Region 8842 decayed slowly and was quiet, the region is spotless early on Jan.28. Region 8843 decayed into spotless plage. Region 8844 did not change significantly and remains capable of C class flaring. Region 8845 was quiet and stable, as was region 8846. Region 8847 decayed into spotless plage. Region 8848 was mostly quiet and stable but could produce isolated C flares. Flares and CMEs No significant flaring was observed on January 27. A large coronal mass ejection was observed below the south pole starting at 17:30 UTC in LASCO C2 images. The source of the CME was highly likely a backside event. The background x-ray flux is at the class B3 level. Coronal holes A large trans equatorial coronal hole will rotate into a geoeffective position on January 25-30. Forecast The geomagnetic field is expected to be unsettled to minor storm on January 28 and quiet to active on January 29 to February 2. 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 8838 20000118 N12W54 plage 8840 20000121 1 S24W63 0000 AXX 8841 20000121 9 S30W09 0140 CSO 8842 20000123 2 S16W66 0000 BXO 8843 20000123 N14W40 plage 8844 20000124 14 N05W60 0200 DAI 8845 20000125 9 S16W06 0040 CAO 8846 20000126 2 N38E39 0010 BXO 8847 20000126 S26W41 plage 8848 20000126 3 S08E66 0030 CAO Total number of sunspots: 40 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 2000.01 162.1 (1) 129.6 (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]