Solar Terrestrial Activity Report [Image] Last update May 8, 2001 at 04:05 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 minor storm on May 7. Solar wind speed ranged between 358 and 419 km/sec. Solar flare activity was low. Solar flux was 138.3, the planetary A index was 17 (3-hour K indices: 4543 3332, Boulder K indices: 3542 3321). Region 9445 decayed further but remains capable of producing C class flares and perhaps a minor M class flare. Region 9447 decayed slowly and has rotated off the visible disk. Region 9448 was quiet and stable, as were regions 9449, 9450 and 9451. New region 9452 rotated into view at the southeast limb. The region appears to be decaying and could soon become spotless. Flares and CMEs A total of 4 C class events were recorded on May 7. Region 9445 produced a C3.9 long duration event peaking at 12:20 and a C2.2 flare at 15:59 UTC. LASCO images recorded two full halo CMEs after 10h UTC from one or two sources well behind the northwest limb. The event causing the CMEs must have been very energetic as a proton event began at Earth a few hours later. So far the above 10 MeV proton flux has peaked at 28 pfu. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the northern hemisphere could rotate into a geoeffective position on May 10-12. Forecast The geomagnetic field is expected to be quiet to unsettled on May 8-9. 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 9442 2001.04.26 N26W82 plage 9444 2001.04.28 S11W55 plage 9445 2001.04.28 15 N25W42 0110 FAO 9447 2001.04.30 3 N12W84 0120 EAO 9448 2001.05.01 6 N22W06 0130 CSO 9449 2001.05.02 2 S17E04 0090 CAO 9450 2001.05.04 4 S02W49 0020 CSO 9451 2001.05.04 2 S21E38 0120 HSX 9452 2001.05.07 1 S09E67 0020 HSX Total number of sunspots: 33 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) 2001.05 165.1 (1) 33.8 (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]