Solar Terrestrial Activity Report [Image] Last update May 7, 2001 at 04:20 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 unsettled on May 6. Solar wind speed ranged between 314 and 407 km/sec. A coronal stream originating from a coronal hole in the southern hemisphere began to influence the geomagnetic field late in the day. Solar flare activity was low. Solar flux was 148.0 (the measurement at 17 UTC was used because a long duration event enhanced the reading at 20 UTC), the planetary A index was 7 (3-hour K indices: 1022 3322, Boulder K indices: 1022 2312). Region 9442 decayed slowly and was spotless by late evening. Region 9445 decayed quickly and has lost most of its spots and more than half of its areal coverage early on May 7 compared to one day earlier. Region 9447 decayed further and was quiet, the region is rotating off the visible disk. Region 9448 was quiet and stable, as was region 9449. Region 9450 decayed slowly and could become spotless late today. Region 9451 was quiet and stable. Flares and CMEs A total of 2 C class events were recorded on May 6. Region 9445 produced a long duration C7.9 event peaking at 20:11 UTC. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on May 10-12. Forecast The geomagnetic field is expected to be quiet to active on May 7 and 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 fair to 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 AreaClassification Comment 9441 2001.04.26 N05W86 plage area should 9442 2001.04.26 1 N26W69 0050 HSX have been 0010 or 0020 9444 2001.04.28 S11W42 plage 9445 2001.04.28 34 N23W30 0180 FAO 9447 2001.04.30 6 N11W71 0200 EAO 9448 2001.05.01 4 N21E07 0100 HAX 9449 2001.05.02 2 S17E17 0080 HAX 9450 2001.05.04 2 S03W36 0020 HSX 9451 2001.05.04 1 S20E52 0070 HAX Total number of sunspots: 50 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) 2001.05 169.5 (1) 30.5 (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]