Solar Terrestrial Activity Report [Image] Last update July 23, 2000 at 07:50 UTC. /Because of my vacation the text on this page will be updated occasionally until July 31. No charts will be produced until normal daily updates start on August 4/ [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, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update July 1, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update July 1, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update April 12, 2000)] Recent development Solar flare activity was moderate on July 22. Solar wind speed was in the range 398-477 km/sec. The geomagnetic field was quiet to minor storm. The planetary A index was 18 (Kp: 2345 3433). Solar flux was 251. Region 9081 was quiet and stable and will rotate off the visible disk early on July 24. Region 9084 was quiet and stable and has rotated over the west limb. Region 9085 decayed fairly quickly and is not likely to produce further proton flares. Region 9087 decayed slowly but could still produce a major flare. Region 9088 decayed and was quiet, the region is rotating over the west limb. Region 9090 was mostly unchanged and remains capable of generating an isolated major flare. Regions 9091, 9094 and 9096 were quiet and stable. Region 9095 could produced further C class flares. Region 9097 did not change significantly and remains capable of isolated major flaring. Region 9099 was quiet and stable. New regions 9100 and 9101 rotated into view at the southeast limb. Flares and CMEs A total of 4 C and 2 M class events were observed on July 22. Region 9095 produced an impulsive C7.2 flare at 04:22 and an impulsive C6.3 flare at 16:53 UTC. Region 9090 generated an impulsive C8.4 flare at 06:21 and an M1.0/1F flare at 07:11 UTC. Region 9097 was the source of a C6.0 flare at 09:07 UTC. Region 9085 produced a surprising M3.7/2N long duration event which peaked at 11:34 UTC. This was a proton producing event too and a weak above 10 MeV event peaked at 14:05 UTC at 17 pfu. A weak type IV sweep and a moderately strong type II sweep were detected as well and there is a minor chance of a terrestrial impact on July 25 from the accompanying CME. July 21: Region 9090 generated an impulsive major M5.5/2B flare at 14:37. A weak type II sweep was detected and a weak CME may have been produced. If so the CME could cause unsettled to minor storm conditions at Earth on July 24 July 20: Region 9087 generated a long duration M3.6/1F flare peaking at 10:06 UTC. A weak type IV sweep was recorded and an Earth directed CME may have been produced, if so the CME could arrive on July 23. Region 9090 was the source of a C5.7 flare at 16:39. This event was associated with a moderately strong type II sweep and a likely CME. Given the position of the flare the CME could well be Earth directed and cause unsettled to minor storm conditions on July 23. The background x-ray flux is at the class C1-C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be to quiet to active on July 23-24, possibly with minor storm intervals. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9081 20000711 1 N05W75 0040 HSX 9084 20000712 1 N21W94 0030 HSX 9085 20000712 12 N14W61 0090 EAO 9087 20000714 50 S12W39 0670 FKC gamma-delta 9088 20000714 2 N21W78 0070 DAO 9089 20000715 N13W49 plage 9090 20000716 42 N11W08 0340 FKI beta-gamma 9091 20000716 1 S06W11 0030 HSX 9092 20000717 S25W75 plage 9093 20000717 S12W62 plage 9094 20000717 1 S23W02 0030 HSX 9095 20000717 11 N22W54 0060 DAO 9096 20000718 5 S12E20 0030 DSO 9097 20000718 21 N06E25 0630 EKC beta-gamma 9098 20000719 S02W61 plage 9099 20000719 1 N13E37 0060 HSX 9100 20000722 1 S32E60 0040 HSX 9101 20000722 1 S15E66 0020 HRX Total number of sunspots: 150 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.06 169.8 137.7 93.1 (+2.6) 1999.07 165.6 113.5 94.3 (+1.2) 1999.08 170.7 93.7 97.5 (+3.2) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 (114.0 predicted, +3.0) 2000.02 174.1 112.9 (116.8 predicted, +2.8) 2000.03 208.2 138.5 (119.5 predicted, +2.7) 2000.04 184.2 125.3 (121.6 predicted, +2.1) 2000.05 184.9 120.8 (122.4 predicted, +0.8) 2000.06 179.8 124.9 2000.07 212.8 (1) 180.9 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz. 2) Unofficial, accumulated value. The official value 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]