Solar Terrestrial Activity Report [Image] Last update August 1, 2001 at 04:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update July 2, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update July 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was unsettled to active on July 31. Solar wind speed ranged between 332 and 616 km/sec, gradually increasing all day under the influence of a coronal hole stream. Solar flare activity was low. Solar flux was 116.8, the planetary A index was 23 (3-hour K indices: 3443 4433, Boulder K indices: 3432 4433). Region 9557 developed slowly and was mostly quiet. Region 9559 decayed and was spotless early in the day. New region 9561 developed slowly and will likely continue to produce C flares. Region 9562 was mostly unchanged and could produce C and perhaps minor M class flares. New region 9563 emerged briefly near the northeast limb, no spots were visible late in the day. Flares and CMEs A total of 3 C class events were recorded on July 31. Region 9561 produced a C1.8 flare at 12:06 and a C2.6 flare at 17:20 UTC. The largest flare of the day was an optically uncorrelated C6.0 event at 04:07 UTC. The background x-ray flux is at the class B2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on August 1-2. 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 no. Location region numbered sunspots at Area Classification Comment midnight 9552 2001.07.23 N13W89 plage 9553 2001.07.23 N14W72 plage 9555 2001.07.24 S09W38 plage 9557 2001.07.26 15 S20E08 0120 EAI 9559 2001.07.27 2 S22W38 0010 BXO 9560 2001.07.29 N18E20 plage 9561 2001.07.30 11 S12E49 0100 DAO 9562 2001.07.30 6 N06E58 0210 EAO beta-gamma? 9563 2001.07.31 1 N24E57 0010 AXX Total number of sunspots: 35 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 (+3.1) 2000.04 184.2 125.5 120.8 (+0.9) cycle 23 sunspot max. 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 170.1 119.7 (+1.0) 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 (109.6 predicted, -2.5) 2001.02 146.6 80.6 (104.8 predicted, -4.8) 2001.03 177.7 113.5 (101.2 predicted, -3.6) 2001.04 177.7 108.2 (100.0 predicted, -1.2) 2001.05 147.1 97.3 (99.3 predicted, -0.7) 2001.06 173.0 134.0 (96.6 predicted, -2.7) 2001.07 131.3 (1) 124.6 (2) (94.7 predicted, -1.9) 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]