Solar Terrestrial Activity Report [Image] Last update August 13, 2000 at 05:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 4, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 4, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 4, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was active to very severe storm on August 12. Solar wind speed ranged between 509 and 740 km/sec, slowly decreasing towards the end of the day as the impressive disturbance weakened. Solar flare activity was moderate. Solar flux was 189, the planetary A index was 109 (3-hour K indices: 5787 7754, Boulder K indices: 4776 5533). Region 9110 just behind the southwest limb was the apparent source of an M1.1 flare at 09:56 UTC. Proton flux enhancements very observed at times later in the day and may have been related to this flare. Region 9114 decayed slowly but could produce occasional C and minor M class flares. Region 9115 decayed slowly and was quiet Region 9121 was quiet and stable. Region 9122 decayed slowly and was quiet. Region 9123 was mostly unchanged and quiet. Region 9124 could produce further C class flares, the region is located in a large plage field and could develop quickly if new flux emerge. Region 9125 developed quickly and has a weak magnetic delta configuration. C class flares are likely and there is a possibility of a minor M class flare. Region 9126 developed slowly and could produce C flares. Region 9127 was quiet and stable. New region 9128 rotated into view at the northeast limb. New region 9129 rotated into view at the southeast limb. Yet another two regions at the southeast and northeast limbs respectively are rotating into view early on August 13. A couple of regions seems to be emerging near the central meridian as well, one in the southern, one in the northern hemisphere. Flares and CMEs A total of 9 C and 1 M class events were recorded on August 12. Region 9124 produced a C2.5 flare at 00:07 and a C3.5 flare at 06:23 UTC. Region 9114 generated a C4.8 flare at 02:04 and a very long duration C3.2 event from 13:48 to 17:07 (peaking at 16:30) UTC. The latter event may have been associated with a partial halo CME, however, lots of activity in the western hemisphere means there could be other sources of the CME. Region 9125 was the source of C3.0 flare at 07:52 and a C2.2 flare at 18:49 UTC. An M1.1 flare at 09:56 UTC appeared in LASCO EIT images to have an origin behind the southwest limb, probably in old region 9110. A filament eruption just to the east of region 9116 began at 07:13 UTC and may have contributed to the CME activity observed off the west limb. August 10: A slow and nearly full coronal mass ejection was observed by LASCO C2 from 06:54 UTC. The CME could be geoeffective as some activity was observed in and near region 9115 (near the central meridian) from 05h UTC onwards. In that case the CME could impact Earth on August 13. The background x-ray flux is at the class B9-C1 level. Coronal holes A small coronal hole in the southern hemisphere was in a geoeffective position on August 12 and could cause unsettled to active intervals on August 15. Forecast The geomagnetic field is expected to be unsettled to minor storm on August 13. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is useless. 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 9114 20000802 9 N10W58 0310 DAI beta-gamma 9115 20000803 4 N17W38 0120 CSO 9116 20000804 S12W41 plage 9120 20000806 S22W56 plage 9121 20000806 2 S33W48 0070 DSO 9122 20000807 8 N22W18 0040 CAO 9123 20000808 6 N20E20 0050 CAO 9124 20000810 6 S12E37 0020 CSO 9125 20000810 25 N25E42 0090 DAI beta-gamma-delta 9126 20000811 7 N07W55 0050 DAO 9127 20000811 3 S38E07 0020 CSO 9128 20000812 4 N11E61 0040 CSO 9129 20000812 2 S05E72 0060 HSX Total number of sunspots: 76 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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 90.1 112.8 (+1.8) 2000.02 174.1 112.9 (117.0 predicted, +4.2) 2000.03 208.2 138.5 (120.7 predicted, +3.7) 2000.04 184.2 125.3 (122.9 predicted, +2.2) 2000.05 184.9 120.8 (123.7 predicted, +0.8) 2000.06 179.8 124.9 (125.3 predicted, +1.6) 2000.07 202.3 169.1 2000.08 167.4 (1) 62.8 (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]