Solar Terrestrial Activity Report [Image] Last update July 24, 2002 at 06:05 UTC. Only occasional updates will be posted until August 3 due to vacation. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update July 1, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update July 1, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update July 1, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to active on July 23. Solar wind speed ranged between 408 and 549 km/sec. Solar flare activity was high. Solar flux was 198.3, the planetary A index was 18 (3-hour planetary K indices: 4343 2344, Boulder K indices: 3232 2323). Region 10035 decayed quickly and had lost most of its penumbral area by midnight. Region 10036 decayed slowly. Further C class flares are possible, as is a minor M class flare. Region 10037 was quiet and stable. Region 10038 was quiet and stable. Region 10039 developed slowly and has a strong magnetic delta in the northern section of the main penumbra. The region remains capable of producing very intense flares, including further X class flares, possibly even an X10+ proton flare. Region 10040 was quiet and stable. Regions 10041 and 10042 decayed slowly and quietly. New region 10043 emerged in the northeast quadrant and has developed moderately quickly. New region 10044 emerged very quickly southwest of region 10039. Magnetograms indicate that the two regions share the same positive polarity area and it is not yet obvious that region 10044 should be split from region 10039. A new region emerged in the northeast quadrant near N04E30 but was not noticed by SEC/NOAA. Flares and CMEs A total of 6 C and 1 X class events was recorded on July 23. Region 10039 produced a major X4.8/2B flare at 00:35 UTC. A large and fast full halo CME was observed. Although the fastest part of the CME headed eastwards, Earth should receive an impact sometime between noon on July 24 and noon on July 25. The CME was well defined even outside of its core and the geomagnetic field could be severely disturbed for 12-24 hours after the impact. Region 10035 generated a C4.0 flare at 09:06 UTC. Region 10036 was the source of a C2.8 at 11:05 and a C3.0 flare at 20:50 UTC, while region 10044 managed a C2.6 flare at 22:56 UTC. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active at least for the first half of July 24. Sometime between noon on July 24 and 25 a CME is expected to impact the magnetosphere causing active to severe storm conditions. 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 Location region numbered no. at Area Classification Comment sunspots midnight 10035 2002.07.15 13 S09W46 0080 DAO 10036 2002.07.15 59 S07W28 0910 EKC 10037 2002.07.17 1 N13W06 0180 HSX 10038 2002.07.21 9 N16E24 0080 DSO beta-gamma-delta ridiculously low area 10039 2002.07.22 22 S15E59 0940 FKC estimate, was near 1000 mills at midnight Classification wrong, should be FKC 10040 2002.07.22 2 S22W14 0010 AXX 10041 2002.07.22 3 N17E04 0020 CAO wrong position, was N17E08 at midnight 10042 2002.07.22 4 S19E26 0010 BXO 10043 2002.07.23 5 N12E56 0020 BXO 10044 2002.07.23 8 S19E57 0140 DAO Total number of sunspots: 126 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 2001.06 173.0 134.0 109.8 (+1.2) 2001.07 131.3 81.8 111.7 (+1.9) 2001.08 162.9 106.4 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 115.5 (+1.5) 2001.12 235.1 132.2 114.6 (-0.9) 2002.01 226.6 114.1 (112.7 predicted, -1.9) 2002.02 205.0 107.4 (111.3 predicted, -1.4) 2002.03 179.5 98.4 (106.6 predicted, -4.7) 2002.04 189.8 120.4 (100.7 predicted, -5.9) 2002.05 178.4 120.8 (96.3 predicted, -4.4) 2002.06 148.7 88.5 (91.7 predicted, -4.6) 2002.07 155.2 (1) 106.3 (2) (86.9 predicted, -4.8) 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]