Solar Terrestrial Activity Report [Image] Last update May 30, 2001 at 02:55 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 29. Solar wind speed ranged between 364 and 478 km/sec. Solar flare activity was low. Solar flux was 138.5, the planetary A index was 10 (3-hour K indices: 4221 3321, Boulder K indices: 3322 2321). Region 9462 was quiet and stable and is rotating off the visible disk. Region 9463 decayed further and lost all trailing spots. The region is rotating off the visible disk. Region 9467 decayed slowly and was quiet. Region 9468 decayed further and was quiet. Region 9472 redeveloped spots but appears to be decaying again and could become spotless today. Region 9474 was mostly unchanged and quiet. Region 9475 developed slowly and has a weak magnetic delta in the trailing spots' penumbra. Region 9477 was spotless all day. Region 9479 decayed and was spotless by early evening. Region 9480 was spotless most of the day. Flares and CMEs A total of 2 C class flares were observed on May 29. Region 9475 produced a C4.4 flare at 05:26 and a C1.5 flare at 07:55 UTC. The background x-ray flux is at the class B3 level. Coronal holes A large southern hemisphere coronal hole was in a geoeffective position on May 28-30. Forecast The geomagnetic field is expected to be quiet to unsettled on May 30. A coronal stream will likely arrive on May 31 and cause unsettled to minor storm conditions until June 2. 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 9462 2001.05.17 1 N20W80 0060 HSX 9463 2001.05.18 1 N08W81 0300 HKX 9464 2001.05.19 S09W67 plage 9465 2001.05.20 S09W60 plage 9466 2001.05.21 S04W64 plage 9467 2001.05.21 1 S06W53 0040 HSX 9468 2001.05.21 4 N05W43 0070 CSO 9471 2001.05.23 S13W81 plage 9472 2001.05.23 4 N13W17 0010 BXO 9473 2001.05.26 N12W26 plage 9474 2001.05.26 8 N19E15 0060 DAO 9475 2001.05.26 7 N18E34 0100 DAO beta-gamma -delta 9477 2001.05.27 1 S16W08 0000 AXX now spotless 9478 2001.05.27 N13W09 plage 9479 2001.05.28 3 N24W71 0020 BXO now spotless 9480 2001.05.28 1 S13E36 0000 AXX now spotless 9481 2001.05.28 N17W57 plage Total number of sunspots: 31 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 2001.05 148.1 (1) 128.7 (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]