Solar Terrestrial Activity Report [Image] Last update August 23, 2001 at 03:55 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 22. Solar wind speed ranged between 484 and 709 km/sec under the influence of a coronal hole stream. Solar flare activity was moderate. Solar flux was 161.5, the planetary A index was 17 (3-hour K indices: 2234 4444, Boulder K indices: 2333 4333). Regions 9575 and 9580 were quiet and stable. Region 9582 decayed significantly losing most of its areal coverage and many spots. Region 9584 decayed and was spotless by early evening. Region 9585 decayed slowly and simplified. Further decay is likely and the region will probably not produce other than isolated C class flares. Region 9587 decayed and was spotless by early evening. Region 9589 developed early in the day, then began to decay. Region 9590 was quiet and stable, however, there is some evidence of development near the southeast section of the large leader spot. Region 9591 rotated further into view revealing a magnetically complex region capable of producing M and X class flares. Any major flare from this region will likely be a large particle event as well. The region is, despite its moderate size, one of the most active ones observed during solar cycle 23. New region 9592 emerged in the southwest quadrant but is already decaying and could soon become spotless. Flares and CMEs A total of 13 C and 1 M class events were observed on August 22, all flares apparently originated from region 9591. The region generated a C6.2 flare at 05:07, a C6.6 flare at 09:08, an M1.0 flare at 12:16, a C3.7 flare at 15:06, a C5.4 flare at 17:37, a C7.5 flare at 18:49, a C7.0 flare at 21:17, a C3.5 flare at 21:50 and a C5.8 flare at 22:56 UTC. August 21: A long duration C2.7 event peaked at 13:03 UTC. Its source was a filament eruption in the southwest quadrant a couple of days rotation from the limb. A partial halo CME was observed in LASCO C3 images in connection with the LDE. There is a possibility that Earth could receive a minor impact from this CME on August 24 or 25. The background x-ray flux is at the class C1-C2 level. Coronal holes A well defined coronal hole in the southern hemisphere will rotate into a geoeffective position on August 23-24. Forecast The geomagnetic field is expected to be quiet to active on August 23-24. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 Location region numbered no. at Area Classification Comment sunspots midnight 9575 2001.08.11 1 N10W73 0130 HSX 9580 2001.08.14 1 N24W30 0090 HSX 9582 2001.08.15 22 N27W20 0120 DSO 9583 2001.08.16 S23W65 plage 9584 2001.08.16 1 S12W24 0000 AXX now spotless 9585 2001.08.16 35 N14W04 0290 EKO 9587 2001.08.17 1 S10W14 0000 AXX now spotless 9589 2001.08.20 9 N16W46 0050 DAO 9590 2001.08.20 2 S28E50 0210 HAX 9591 2001.08.21 8 S17E63 0280 FKO beta-gamma-delta 9592 2001.08.22 3 S09W59 0020 BXO Total number of sunspots: 83 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) 2001.08 152.3 (1) 113.0 (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]