Solar Terrestrial Activity Report [Image] Last update August 19, 2001 at 05:05 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to active on August 18. Solar wind speed ranged between 448 and 579 km/sec. Solar flare activity was low. Solar flux was 156.1, the planetary A index was 14 (3-hour K indices: 3332 3433, Boulder K indices: 3331 4424). Region 9573 was quiet and stable, as was region 9575. Region 9579 decayed and was spotless by late evening. Region 9580 was quiet and stable. Region 9581 developed slowly and was quiet. Region 9582 developed slowly and became more complex. Further C class flaring is likely. Region 9584 was quiet and stable, some decay was observed towards the end of the day. Region 9585 developed very quickly and could produce minor M class flares. Region 9586 decayed and was spotless by late evening. Region 9587 was quiet and stable. Flares and CMEs A total of 9 C class events were recorded on August 18. Region 9582 produced a C3.5 flare at 03:28, a C1.4 flare at 05:15, a C1.9 flare at 06:54, a C3.1 flare at 11:17 and a C2.8 flare at 12:51 UTC. Region 9586 was the source of a C1.1 flare at 08:32 UTC. The background x-ray flux is at the class B5 level. Coronal holes A coronal hole in the northern hemisphere was in a possible geoeffective position on August 16-18. Forecast The geomagnetic field is expected to be quiet to unsettled with a possibility of active intervals on August 19-20. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor to useless. 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 9571 2001.08.06 N06W82 plage 9573 2001.08.08 1 S08W62 0030 HSX 9575 2001.08.11 4 N11W12 0150 CSO 9579 2001.08.14 1 S24W63 0020 HRX 9580 2001.08.14 1 N25E22 0100 HSX 9581 2001.08.15 3 S26W50 0040 DSO 9582 2001.08.15 8 N28E33 0070 DAO beta-gamma 9583 2001.08.16 S23W13 plage 9584 2001.08.16 6 S13E36 0040 CAO 9585 2001.08.16 18 N15E50 0230 DAI beta-gamma 9586 2001.08.17 5 S16W62 0020 CRO 9587 2001.08.17 1 S11E43 0020 HSX Total number of sunspots: 48 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.7 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.2 (-2.4) 2000.10 167.4 99.4 114.5 (-1.7) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 108.8 (-3.3) 2001.02 146.6 80.6 (103.3 predicted, -5.5) 2001.03 177.7 113.5 (99.7 predicted, -3.6) 2001.04 177.7 108.2 (98.5 predicted, -1.2) 2001.05 147.1 97.3 (97.9 predicted, -0.6) 2001.06 173.0 134.0 (95.1 predicted, -2.8) 2001.07 131.3 82.2 (93.2 predicted, -1.9) 2001.08 150.9 (1) 91.5 (2) (93.8 predicted, +0.6) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ Do you know about the survey which will be held this Summer among the listeners of WWV and WWVH? There is information about this survey at 16 minutes past the hour on WWV and at 47 minutes past the hour on WWVH. If you want to participate send an email with your name and address. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]