Solar Terrestrial Activity Report [Image] Last update May 4, 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 unsettled on May 3. Solar wind speed ranged between 356 and 397 km/sec. Solar wind density has been increasing slowly over the past day, indicating the approach of a coronal stream. Solar flare activity was low. Solar flux was 172.3, the planetary A index was 7 (3-hour K indices: 1123 2232, Boulder K indices: 2123 1212). Region 9436 was quiet and stable and rotated off the visible disk early on May 4. Region 9441 decayed slowly and was quiet. Regions 9442 and 9444 were quiet and stable. Region 9445 decayed slowly but could still produce minor M class flares. Region 9447 developed further and is capable of minor M class flare production. Region 9448 was quiet and stable, as was region 9449. Flares and CMEs A total of 6 C class events were recorded on May 3. Region 9445 produced a C2.3 flare at 04:05 UTC. Region 9447 generated a long duration C2.9 event peaking at 08:31 and a C2.3 flare at 16:02 UTC. The background x-ray flux is at the class B7 level. Coronal holes A trans equatorial coronal hole was in a geoeffective position on May 1-3. Forecast The geomagnetic field is expected to be quiet to active on May 4-5 with a possibility of minor storm intervals. 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 Area Classification Comment 9436 2001.04.21 1 S11W85 0050 HSX 9437 2001.04.21 N09W84 plage 9440 2001.04.26 N08W73 plage 9441 2001.04.26 13 N07W44 0220 EAO beta-gamma 9442 2001.04.26 1 N27W30 0050 HSX 9443 2001.04.27 S10W57 plage 9444 2001.04.28 4 S11W01 0010 AXX 9445 2001.04.28 30 N25E10 0240 FAI beta-gamma 9446 2001.04.29 S05W75 plage 9447 2001.04.30 21 N12W27 0090 EAI beta-gamma 9448 2001.05.01 6 N21E47 0100 CAO 9449 2001.05.02 1 S16E57 0070 HSX Total number of sunspots: 77 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) 2001.05 177.7 (1) 15.7 (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]