Solar Terrestrial Activity Report [Image] Last update August 25, 2000 at 04:05 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 quiet to unsettled on August 24. Solar wind speed ranged between 310 and 429 km/sec. Solar flare activity was low. Solar flux was 130.6, the planetary A index was 10 (3-hour K indices: 3332 2232, Boulder K indices: 3431 2221). Region 9129 was quiet and stable and has rotated off the visible disk. Region 9131 developed slowly and was quiet, the region will rotate over the west limb on August 26. Region 9138 decayed slowly and was quiet. Region 9139 decayed slowly and could produce occasional C class flares. Region 9140 developed slowly and was quiet. Region 9141 decayed into spotless plage. New region 9142 rotated into view at the northeast limb. New region 9143 rotated partly into view at the southeast limb and will likely produce further C class flares. Flares and CMEs A total of 3 C class events were recorded on August 24. Region 9143 produced a C1.2 flare at 13:51 UTC. A region behind the northwest limb was the source of a long duration C6.2 event peaking at 09:17 UTC. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on August 26-28. Forecast The geomagnetic field is expected to be quiet to unsettled August 25-27. 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 9129 20000812 1 S04W88 0050 HRX 9131 20000813 5 N14W72 0210 DAO 9132 20000814 N20W78 plage 9134 20000814 N08W64 plage 9137 20000819 N24W19 plage 9138 20000819 1 S32E01 0030 HSX 9139 20000820 6 S10W31 0150 DAO 9140 20000822 6 N09E41 0030 CRO 9141 20000823 N16W21 plage 9142 20000824 1 N16E71 0030 HSX 9143 20000824 2 S18E70 0060 CSO Total number of sunspots: 22 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 (115.7 predicted, +2.9) 2000.03 208.2 138.5 (118.2 predicted, +2.5) 2000.04 184.2 125.3 (120.4 predicted, +2.2) 2000.05 184.9 120.8 (121.2 predicted, +0.8) 2000.06 179.8 124.9 (122.8 predicted, +1.6) 2000.07 202.3 169.1 2000.08 166.0 (1) 132.1 (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]