Solar Terrestrial Activity Report [Image] Last update May 31, 2002 at 04:00 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 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to unsettled on May 30. Solar wind speed ranged between 377 and 548 km/sec. A weak solar wind shock was observed at SOHO at 01:24 UTC, this was likely the arrival of the CME associated with a filament eruption in the northeast quadrant on May 27. Solar wind speed increased abruptly from 460 to 510 km/sec. Solar flare activity was moderate. Solar flux was 180.1, the planetary A index was 9 (3-hour K indices: 2133 3322, Boulder K indices: 3122 3222). Region 9961 was quiet and stable. Region 9963 decayed slowly. Minor M class flares are possible. The plage near the region is considerably brighter than just a day ago. Region 9965 decayed slowly and quietly. Region 9967 was spotless for the second consecutive day but was nevertheless observed by SEC/NOAA with a few spots. The region may actually have reemerged early on May 31. Region 9969 decayed and was spotless by the end of the day. Region 9970 decayed slowly and quietly. Region 9972 lost several of its trailing spots, however, the leading penumbra increased its size. Region 9973 decayed slowly and lost some spots and penumbral area. The region has become simpler but still has major flare potential. Region 9974 was quiet and stable. Region 9975 gained a few spots but remains small and simple. The plage near the region is less bright than yesterday. New region 9976 emerged early in the day in the southeast quadrant. Flares and CMEs A total of 8 C and 3 M class events were recorded on May 30. Region 9973 produced a C1.2 flare at 00:11 and a long duration M1.6 event peaking at 17:24 UTC. A region behind the west limb (possibly old region 9957) was the source of a long duration M1.3 event peaking at 05:32, a C3.2 flare at 08:41 and a long duration C4.1 event peaking at 14:32 UTC. A fairly large and wide CME was observed off the west limb in connection with the M1 event. Region 9963 generated a C1.6 flare at 19:50 UTC. Quite a bit of activity was observed at the southeast limb at the end of the day. A long duration C4.0 event peaked at 23:20 while a long duration M2.4 event began at 23:50 and peaked at 00:16 UTC on May 31. The source of these events may have been an eruptive prominence. The M2 event was associated with a large, wide and fast partial halo CME off the southeast limb. There is a slight chance that the outer edge of this CME could reach the Earth on June 2. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be mostly quiet to unsettled on May 31 to 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 Location region numbered no. at Area Classification Comment sunspots midnight 9960 2002.05.18 N14W82 plage 9961 2002.05.19 1 S21W72 0110 HSX 9962 2002.05.20 N16W74 plage 9963 2002.05.20 12 N16W56 0260 DKC beta-gamma 9965 2002.05.22 5 S08W47 0040 CSO 9966 2002.05.23 N10W62 plage 9967 2002.05.23 3 N12W51 0010 BXO actually spotless 9968 2002.05.24 S14W52 plage 9969 2002.05.25 5 N09E04 0010 BXO now spotless 9970 2002.05.26 8 N06E01 0120 DSO 9971 2002.05.28 N21W26 plage 9972 2002.05.28 11 S21E31 0110 DSO 9973 2002.05.28 23 S16E48 0880 EKC beta-gamma 9974 2002.05.29 1 N18E45 0040 HSX 9975 2002.05.29 5 N23E50 0020 BXO 9976 2002.05.30 6 S10E01 0020 BXO Total number of sunspots: 80 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.04 177.7 107.7 107.5 (+2.7) 2001.05 147.1 96.6 108.6 (+1.1) 2001.06 173.0 134.0 109.8 (+1.2) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 (114.7 predicted, +0.7) 2001.12 235.1 132.2 (112.5 predicted, -2.2) 2002.01 226.6 113.9 (109.8 predicted, -2.7) 2002.02 205.0 108.0 (108.4 predicted, -1.4) 2002.03 179.5 98.1 (104.2 predicted, -4.2) 2002.04 189.8 120.4 (98.3 predicted, -3.9) 2002.05 178.3 (1) 197.6 (2) (93.8 predicted, -4.5) 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 25-45% 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. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]