Solar Terrestrial Activity Report [Image] Last update May 9, 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 May 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update April 8, 2001)] Recent development The geomagnetic field was quiet to active on May 8. Solar wind speed ranged between 328 and 569 km/sec. A coronal stream began to influence the field from approximately 09 UTC and gradually strengthened. Minor storm conditions were observed early on May 9. Solar flare activity was low. Solar flux was 128.7, the planetary A index was 14 (3-hour K indices: 2133 3444, Boulder K indices: 1132 2333). Region 9445 decayed further and has only a few small spots left early on May 9. If the region continues to decay it could become spotless by the end of the day. Region 9448 developed slowly and was quiet. Regions 9449, 9451 and 9452 were quiet and stable. Region 9450 decayed slowly and was spotless by early evening. Flares and CMEs A total of 2 C class events were recorded on May 8. Region 9445 produced a C9.9/1F long duration event peaking at 00:55 UTC. The background x-ray flux is at the class B3 level. Coronal holes A large coronal hole in the northern hemisphere could rotate into a geoeffective position on May 10-13. The coronal hole is not particularly well defined and it is uncertain how strong its coronal stream will become. Forecast The geomagnetic field is expected to be quiet to minor storm on May 9 and quiet to unsettled on May 10-11. 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 at region numbered sunspots midnight Area Classification Comment 9444 2001.04.28 S11W68 plage 9445 2001.04.28 9 N24W54 0100 FAO 9448 2001.05.01 8 N22W16 0110 CSO 9449 2001.05.02 5 S16W07 0070 CSO 9450 2001.05.04 2 S02W66 0020 AXX 9451 2001.05.04 3 S21E26 0120 HAX 9452 2001.05.07 1 S09E54 0020 HSX Total number of sunspots: 28 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.02 174.1 112.9 116.8 (+3.9) 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 (112.5 predicted, -2.0) 2000.12 173.6 104.5 (109.9 predicted, -2.6) 2001.01 166.6 95.6 (106.2 predicted, -3.7) 2001.02 146.6 80.1 (101.8 predicted, -4.4) 2001.03 177.7 114.2 (98.2 predicted, -3.6) 2001.04 177.7 108.2 (97.0 predicted, -1.2) 2001.05 160.5 (1) 36.6 (2) (96.3 predicted, -0.7) 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]