Solar Terrestrial Activity Report [Image] Last update May 19, 2002 at 03:55 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 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 to minor storm on May 18. Solar wind speed ranged between 337 and 536 km/sec. A solar wind shock was observed at SOHO at 19:29 UTC with a sudden increase in solar wind speed from 350 to 520 km/sec. The interplanetary magnetic field was at times moderately southwards after the initial shock and this caused minor geomagnetic storming for the remainder of the day. Solar flare activity was low. Solar flux was 163.0, the planetary A index was 15 (3-hour K indices: 2112 3355, Boulder K indices: 2111 2345). Region 9945 decayed further and is rotating quietly over the southwest limb. Region 9948 was unchanged and quiet. A minor M class flare is possible. Region 9950 decayed slowly and quietly. Region 9951 reemerged briefly with a few spots, the region is spotless early on May 19. Region 9954 was mostly unchanged and quiet. Region 9955 was quiet and stable. Region 9957 decayed slowly in the southernmost spot section and plage intensity near the region decreased. The region still has a magnetic delta structure and may be capable of producing a major flare. Region 9958 was quiet and stable. New region 9960 rotated into view at northeast limb. The region was much less active than on the previous day and appears to be decaying. The inversion line in the region is oriented mostly east-west, however, just east of the center of the region the negative polarity field cuts through the positive polarity field. This is likely where the energetic flares observed on May 17 had their origin. SEC/NOAA has apparently decided that the new region observed yesterday in the southwest quadrant does not exist. The region is currently decaying and is likely to become spotless today. Only a single small spot was visible at midnight when the region was positioned at S24W66. Flares and CMEs A total of 6 C class events were recorded on May 18. Region 9957 produced a C2.6 flare at 09:25, a C3.4 flare at 15:44 and a C2.2 flare at 18:29 UTC. A filament eruption near region 9955 was recorded as a long duration C3.0 event peaking at 11:39 UTC. The background x-ray flux is at the class B7 level. Coronal holes A recurrent trans equatorial coronal hole will rotate into a geoeffective position on May 21. The size of this coronal hole has shrunk considerably over the last rotation and development in regions 9957 and 9958 could cause a further reduction in size before the coronal hole is in a geoeffective position. Forecast The geomagnetic field is expected to be unsettled to major storm on May 19 and quiet to unsettled on May 20-21. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 Location region numbered no. at Area Classification Comment sunspots midnight 9945 2002.05.07 2 S02W84 0180 HSX area too large 9946 2002.05.08 S06W69 plage 9948 2002.05.10 2 S21W31 0380 CHO 9950 2002.05.11 1 S05W51 0020 HSX 9951 2002.05.12 3 N12W12 0010 BXO now spotless 9952 2002.05.13 S15W87 plage 9954 2002.05.15 4 S22E27 0130 DAO 9955 2002.05.15 1 S14E28 0030 HSX 9956 2002.05.16 S08W30 plage 9957 2002.05.16 27 N08E47 0810 EKC beta-gamma-delta 9958 2002.05.17 6 N04E37 0100 CSO 9959 2002.05.17 N10W04 plage 9960 2002.05.18 4 N15E74 0100 DAO beta-gamma Total number of sunspots: 50 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) 2002.05 175.9 (1) 117.2 (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]