Solar Terrestrial Activity Report [Image] Last update August 24, 2001 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 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 23. Solar wind speed ranged between 432 and 588 km/sec. Solar flare activity was low. Solar flux was 169.7, the planetary A index was 12 (3-hour K indices: 3242 3332, Boulder K indices: 3231 2121). Region 9575 was quiet and stable and is rotating over the west limb. Region 9580 was quiet and stable. Region 9582 decayed quickly and could become spotless today. Region 9585 decayed further and was quiet. Region 9589 was mostly unchanged and quiet. Region 9590 developed slowly and was quiet. Region 9591 rotated fully into view and is a complex region capable of producing major flares, including large proton events. Region 9592 was mostly quiet and stable and is about to rotate out of view. New region 9593 emerged at the center of the solar disk. Flares and CMEs A total of 10 C class events were observed on August 23, again with all flares originating in region 9591. The region generated a C7.0 flare at 00:30, a C6.6 flare at 02:05, a C6.9 flare at 03:39, a C8.3 flare at 05:13, a C5.9 flare at 13:49, a C3.3 flare at 14:40 and a C3.8 flare at 18:01 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 level. Coronal holes A well defined coronal hole in the southern hemisphere was in a geoeffective position on August 23-24. Forecast The geomagnetic field is expected to be quiet to active on August 24, quiet to unsettled on August 25 and quiet to minor storm on August 26. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 N10W86 0090 HSX 9580 2001.08.14 2 N24W43 0110 HSX 9582 2001.08.15 14 N28W33 0050 CSO 9583 2001.08.16 S23W78 plage 9584 2001.08.16 S12W37 plage 9585 2001.08.16 38 N14W16 0240 DAO 9587 2001.08.17 S10W27 plage 9589 2001.08.20 10 N16W59 0060 CAO 9590 2001.08.20 4 S28E37 0190 HAX 9591 2001.08.21 28 S17E53 0730 FKI beta-gamma-delta 9592 2001.08.22 5 S08W73 0080 DSO 9593 2001.08.23 2 N00E01 0010 BXO Total number of sunspots: 104 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) 2001.08 153.1 (1) 119.2 (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]