Solar Terrestrial Activity Report [Image] Last update May 11, 2001 at 04:10 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 unsettled to minor storm on May 10. Solar wind speed ranged between 385 and 484 km/sec. Solar flare activity was low. Solar flux was 130.4, the planetary A index was 28 (3-hour K indices: 5554 3333, Boulder K indices: 5554 3223). Region 9445 was spotless all day (but not according to SEC/NOAA which mistakenly reported the region as having one spot). Regions 9448, 9449, 9451 and 9452 were mostly quiet and stable. Region 9453 decayed and was spotless by the end of the day. New region 9454 rotated into view at the northeast limb and has minor M class flare potential. Another new region emerged just south of region 9452 in the southeast quadrant but was not noticed by SEC/NOAA. Flares and CMEs A total of 3 C class events were recorded on May 10. Region 9449 produced a C1.8 flare at 10:26 UTC. Region 9454 was the source of a long duration C6.1 event peaking at 15:19 UTC. The flare was associated with a weak type II sweep as well as a coronal mass ejection off the east limb. A long duration C5.6 event peaked at 02:03 UTC and has its origin just behind the northwest limb. A moderately large CME was observed over the west limb. The LDE may have triggered an eruption in a filament near the northwest limb on the visible disk. The background x-ray flux is at the class B3 level. Coronal holes A large, poorly defined coronal hole (could be just a large area with a weak corona) in the northern hemisphere was in a geoeffective position on May 9-12. If there is any coronal stream from this feature, it is likely to be weak. Forecast The geomagnetic field is expected to be quiet to unsettled on May 11-13. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very 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 region was 9445 2001.04.28 1 N21W88 0030 HSX spotless all day! 9448 2001.05.01 2 N21W44 0110 HSX 9449 2001.05.02 5 S17W34 0060 CSO 9451 2001.05.04 6 S21E00 0130 CAO 9452 2001.05.07 1 S09E27 0010 HRX 9453 2001.05.09 1 S08W41 0010 HRX 9454 2001.05.10 8 N15E74 0300 EAO beta-gamma Total number of sunspots: 24 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) 2001.05 154.4 (1) 42.8 (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]