Solar Terrestrial Activity Report [Image] Last update May 16, 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 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 15. Solar wind speed ranged between 387 and 516 km/sec under the influence of a coronal stream. Solar flare activity was moderate. Solar flux was 142.1, the planetary A index was 16 (3-hour K indices: 2244 2443, Boulder K indices: 2244 2333). Region 9451 was quiet and stable, the region will rotate off the visible disk on May 17. Region 9454 decayed slowly and was quiet. Region 9455 appears to be slowly decaying. Further minor M class flares are possible. Region 9456 was quiet and decayed slowly. Region 9458 was quiet and stable. Regions 9459 and 9460 were quiet and in slow decay, both regions are spotless early on May 16. New region 9461 rotated partly into view at the northeast limb, the region may be the return of old region 9433. Flares and CMEs A total of 5 C and 1 M class events were recorded on May 15. Region 9455 produced an M1.0/1N impulsive flare at 03:00 UTC. A moderate type II sweep and a weak type IV was recorded. The CME associated with the event does not appear to have been geoeffective. Region 9455 was the source of a C3.5 flare at 08:45 and a C2.1 flare at 09:16 UTC. A very long duration C4.0 event peaked at 19:40 and had its origin right behind the northeast limb and was probably caused by a prominence eruption. The background x-ray flux is at the class B9 level. Coronal holes What appears to be a small coronal hole was in a geoeffective position on May 15 and could cause a few unsettled to active intervals on May 18. Forecast The geomagnetic field is expected to be quiet to active on May 16. 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 9451 2001.05.04 1 S21W68 0120 HSX 9452 2001.05.07 S10W37 plage 9454 2001.05.10 23 N12E05 0280 EAO beta-gamma 9455 2001.05.11 22 S17W38 0180 FAI beta-gamma 9456 2001.05.12 9 N07W45 0050 DSO 9457 2001.05.13 S21W20 plage 9458 2001.05.14 6 S12W60 0040 CSO 9459 2001.05.14 2 N26W24 0010 BXO 9460 2001.05.14 1 S24E48 0000 AXX 9461 2001.05.15 2 N15E76 0010 BXO Total number of sunspots: 66 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) 2001.05 149.2 (1) 63.4 (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]