Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update January 18, 2000 at 04:45 UTC. Minor update posted at 10:32 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 on January 17. Solar wind speed ranged between 343 and 428 km/sec. Solar flare activity was low. Solar flux was 196.4, the planetary A index was 3 (3-hour Kp indices: 1011 1221, Boulder K indices: 1021 0200). Region 8821 decayed slowly and was quiet. Region 8824 decayed slowly and was generally quiet. Isolated M flares are possible. Region 8825 developed slowly and was quiet. Region 8828 decayed slowly and was quiet. Region 8829 was mostly quiet and stable. Region 8830 reemerged with a few spots. Region 8831 developed further and has minor M class flaring potential. Region 8832 was quiet and stable, as was region 8833. Region 8834 was quiet and stable and will rotate off the visible disk today. Regions 8835 and 8836 were quiet and stable. Comment added at 10:32 UTC on January 18: An M1.2 long duration event peaked at 10:08 UTC. The source of the flare is not yet certain, could be either of regions 8824, 8830 and 8831. Another update will be posted when more information and images are available. Flares and CMEs 6 C flares were recorded on January 17. The only 2 optically correlated flares were produced by region 8823 (a C3.1 flare at 06:19 UTC) and region 8829 (a C1.7 flare at 21:47 UTC). The most energetic event of the day was a C7.1 flare at 00:28 UTC. January 16: A fairly large filament eruption was observed in LASCO EIT movies. The event was first observed at 03:12 UTC and occurred 15-25 degrees east of the central meridian and spanned 15-20 degrees on either side of the solar equator. There may have been a weak CME in LASCO C2 images. The CME could be geoeffective. The background x-ray flux is at the class B7 level. Coronal holes A small, poorly defined coronal hole in the southern hemisphere will move into a geoeffective position on January 17-18 and could cause a slight increase in geomagnetic activity on January 20 or 21. Forecast The geomagnetic field is expected to be mostly quiet on January 18-19. On January 19-20 there is a possibility of an impact from CME produced by a filament eruption on January 16. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally fair. 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 8820 20000106 S15W72 plage 8821 20000106 2 N27W60 0070 CSO 8823 20000108 S32W53 plage 8824 20000109 37 S13W30 0270 DAC 8825 20000110 6 N11W30 0030 CRO 8828 20000111 10 S23W21 0070 DAO 8829 20000111 8 N15W04 0120 DSO 8830 20000112 3 S14W49 0010 BXO 8831 20000112 23 S18E14 0270 EAO 8832 20000113 5 S18W54 0030 CRO 8833 20000113 5 N17E26 0120 CSO 8834 20000115 2 S15W87 0030 CRO 8835 20000115 2 N09E30 0000 BXO 8836 20000116 4 S12E37 0010 BXO Total number of sunspots: 107 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 2000.01 166.5 (1) 83.2 (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]