Solar Terrestrial Activity Report [Image] Last update August 17, 2001 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 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 unsettled on August 16. Solar wind speed ranged between 341 and 396 km/sec. Solar flare activity was low. Solar flux was 142.6, the planetary A index was 8 (3-hour K indices: 2102 3332, Boulder K indices: 1101 2322). Region 9570 decayed slowly and was quiet, the region will rotate off the visible disk on August 18. Region 9571 decayed slowly and was quiet, the region will likely become spotless today. Region 9573 decayed further and was quiet. Region 9574 decayed quietly and will rotate over the southwest limb today. Region 9575 was quiet and stable. Region 9577 decayed quietly and will rotate over the northwest limb on August 18. Region 9578 was spotless all day in all available images. Region 9579 decayed quietly. Region 9580 was quiet and stable. Region 9581 developed early in the day, then began to decay. Region 9582 was quiet and in slow decay. New region 9583 emerged in the southeast quadrant. New region 9584 emerged near the southeast limb. New region 9585 rotated into view at the northeast limb. Flares and CMEs Only 1 C class event was recorded on August 16, it was an optically unassigned C3.9 flare at 09:57 UTC. August 14: A long duration C2.3 event peaked at 12:42 UTC. Its source was an extensive filament eruption in the northwest quadrant fairly near the central meridian. A bright full halo CME was observed in LASCO C3 images. This CME should impact Earth sometime between late on August 16 and 18h UTC on August 17 causing active to major storm conditions, possibly with severe storm conditions at high latitudes. The background x-ray flux is at the class B4 level. Coronal holes A coronal hole in the northern hemisphere could rotate into a geoeffective position on August 16-18. Forecast The geomagnetic field is expected to be quiet to major storm on August 17 with a chance of isolated severe storm intervals at high latitudes. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor to useless because of a polar cap absorption event in progress. 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 9570 2001.08.05 1 S11W73 0120 HSX 9571 2001.08.06 1 N06W56 0010 AXX 9573 2001.08.08 1 S09W35 0030 HSX 9574 2001.08.10 3 S04W79 0150 EAO 9575 2001.08.11 4 N12E08 0130 CSO 9577 2001.08.12 3 N13W74 0020 DSO 9578 2001.08.12 1 S10W65 0000 AXX actually spotless 9579 2001.08.14 4 S20W36 0040 CSO 9580 2001.08.14 1 N25E48 0140 HSX 9581 2001.08.15 3 S26W23 0050 CSO 9582 2001.08.15 2 N32E59 0030 AXX 9583 2001.08.16 3 S23E13 0020 DSO 9584 2001.08.16 2 S11E60 0020 BXO 9585 2001.08.16 2 N15E74 0030 BXO Total number of sunspots: 31 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) 81.6 (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]