Solar Terrestrial Activity Report [Image] Last update May 15, 2001 at 04:30 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 14. Solar wind speed ranged between 451 and 658 km/sec under the influence of a weakening coronal stream. Solar flare activity was low. Solar flux was 138.2, the planetary A index was 12 (3-hour K indices: 4341 2332, Boulder K indices: 4341 1231). Region 9451 was quiet and stable. Region 9454 decayed slowly but could produce minor M class flares. Region 9455 was generally unchanged and has minor M class flaring potential. Region 9456 was quiet and decayed slowly. Region 9457 was spotless all day in all available images. New region 9458 emerged in the southwest quadrant. New region 9459 emerged in the northwest quadrant near the central meridian. New region 9460 emerged near the southeast limb but appears to be spotless early on May 15. Old region 9433 is currently at the northeast limb. Flares and CMEs A total of 4 C class events were recorded on May 14. Region 9455 generated a C5.1 flare at 03:24, a C1.7 flare at 05:28, a C1.0 flare at 11:13 and a C2.3 flare at 12:27 UTC. Region 9455 produced an M1.0/1N impulsive flare at 03:00 UTC on May 15. A moderate type II sweep was recorded and there may have been a geoeffective CME. May 13: Region 9455 produced an impulsive M3.6 flare at 03:04 UTC with associated weak type II and IV sweeps and a possibly geoeffective CME. This and the CME from the eruption late on May 12 could reach Earth late on May 15 or early on May 16 and cause unsettled to active conditions. May 12: Region 9455 produced an M3.0/1B flare at 23:35 UTC. The flare was accompanied by a weak type IV sweep and a minor CME where most of the ejected material was observed over the south pole. The CME could be geoeffective but is not likely to cause a strong geomagnetic storm. The background x-ray flux is at the class B4 level. Coronal holes No obvious coronal holes are approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on May 15 due to a coronal stream. There is a possibility of a CME arriving late in the day or early on May 16, this could cause unsettled to active geomagnetic conditions. 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 AreaClassification Comment midnight 9449 2001.05.02 S16W87 plage 9451 2001.05.04 5 S22W52 0120 DSO 9452 2001.05.07 S10W24 plage 9454 2001.05.10 21 N12E18 0320 EAO beta-gamma 9455 2001.05.11 29 S17W24 0180 EAI beta-gamma 9456 2001.05.12 7 N06W32 0060 DSO 9457 2001.05.13 1 S21W07 0000 AXX actually spotless 9458 2001.05.14 3 S11W45 0020 CSO 9459 2001.05.14 2 N26W09 0020 CRO 9460 2001.05.14 1 S24E60 0000 AXX Total number of sunspots: 69 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) 2001.05 149.7 (1) 58.7 (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]