Solar Terrestrial Activity Report [Image] Last update July 29, 2000 at 07:10 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 low on July 28. Solar wind speed was in the range 342-522 km/sec. A fairly strong solar wind shock was observed at 05:43 UTC on July 28 as the CME observed on July 25 reached ACE. Solar wind speed increased abruptly from 340 to 450 km/sec and the interplanetary magnetic field was initially very strongly southwards. Normally major storming is observed in such cases, however, the disturbance peaked at the minor storm level. The geomagnetic field was unsettled to minor storm. The planetary A index was 30 (Kp: 3355 5543). Solar flux was 157.8. Region 9090 decayed further and will complete its rotation off the visible disk today. Regions 9094 and 9096 were quiet and stable, region 9094 will rotate over the west limb today. Region 9097 decayed slowly during the day, fairly quick decay has been observed early on July 29. The region is currently not likely to produce M flares. Regions 9099, 9100, 9101, 9102 and 9104 were all quiet and stable. Region 9103 has developed fairly quickly since the latter half of July 28 and could soon start producing C flares and minor M flares. Regions 9105 and 9106 were mostly quiet and stable. An active region at the southeast limb is rotating onto the disk, C and perhaps minor M class flares are possible. Flares and CMEs A total of 8 C class events were observed on July 28. Region 9105 produced the only optically correlated flare of the day, a C3.5 flare at 21:12 UTC. The background x-ray flux is at the class B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on July 29 and quiet to unsettled on July 30-31. 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 9090 20000716 1 N15W82 0140 HSX 9094 20000717 1 S24W79 0020 AXX 9096 20000718 1 S11W59 0010 AXX 9097 20000718 18 N09W55 0210 DAI 9099 20000719 1 N16W41 0080 HSX 9100 20000722 2 S30W15 0120 CSO 9101 20000722 2 S13W19 0010 BXO 9102 20000725 1 S17E15 0000 AXX 9103 20000726 10 N10E03 0040 DAO 9104 20000726 1 S21E51 0100 HSX 9105 20000727 1 N15E66 0090 HSX 9106 20000727 4 S10W30 0020 BXO Total number of sunspots: 43 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 2000.07 207.9 (1) 222.0 (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]