Solar Terrestrial Activity Report [Image] Last update July 31, 2000 at 06:00 UTC. /Next update (including a chart update) will be posted on August 4 as I will be travelling the next few days./ [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 30. Solar wind speed was in the range 407-494 km/sec. The geomagnetic field was quiet to unsettled. The planetary A index was 10 (Kp: 3312 3222). Solar flux was 149.9. Region 9097 decayed further and was quiet, the region rotated off the visible disk early on July 31. Regions 9099 and 9100 were quiet and stable. Region 9101 decayed into spotless plage. Region 9103 was mostly quiet and stable, occasional C class flares are possible. Regions 9104, 9105 and 9106 were mostly quiet and stable. Region 9107 didn't display any activity of interest. The region could possibly be split into two separate regions. Region 9108 was quiet and stable and has become spotless early on July 31. Region 9109 was quiet and stable, the region has lost all but one spot early on July 31. Flares and CMEs A total of 3 C class events were recorded on July 30. Region 9105 produced a C4.2 flare at 13:18 UTC. The largest flare of the day, a C7.8 flare, was optically uncorrelated. The background x-ray flux is at the class B5 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on July 30-August 1 and could cause unsettled and active intervals on August 2-4. Forecast The geomagnetic field is expected to be quiet to unsettled on July 31 and August 1. Quiet to active is expected for August 2-3. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9096 20000718 S12W85 plage 9097 20000718 5 N08W83 0070 CSO 9099 20000719 1 N16W69 0050 HSX 9100 20000722 1 S29W43 0120 HSX 9101 20000722 S13W44 plage 9102 20000725 S17W11 plage 9103 20000726 15 N11W26 0120 DSO 9104 20000726 1 S20E24 0100 HSX 9105 20000727 1 N16E40 0080 HSX 9106 20000727 4 S10W58 0010 BXO 9107 20000729 5 S18E56 0110 FSO 9108 20000729 1 S12W31 0000 AXX 9109 20000729 4 S06E27 0020 BXO Total number of sunspots: 38 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 2000.07 204.1 (1) 232.4 (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]