Solar Terrestrial Activity Report [Image] Last update August 11, 2000 at 04:10 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 minor storm on August 10. Solar wind speed ranged between 347 and 504 km/sec. A solar wind shock was observed at ACE at 04:06 UTC. The interplanetary magnetic field was mostly strongly southwards after the arrival of the shock and disturbed the geomagnetic field to unsettled to minor storm levels. The disturbance increased in intensity at the very end of the day and early on August 11. Currently major storming is observed and a few stations have reported severe storming. The source of the CME related disturbance is unknown. Solar flare activity was low. Solar flux was 181, the planetary A index was 23 (3-hour K indices: 2344 5335, Boulder K indices: 1254 5444). Region 9110 was somewhat unstable and could produce an additional C flares before departing the visible disk on August 12. Region 9114 was mostly quiet and stable but could produce occasional C and minor M class flares. Region 9115 did not change significantly and was quiet. Region 9116 decayed into spotless plage. Region 9119 decayed slowly and was quiet. Region 9120 decayed into spotless plage. Region 9121 decayed slowly and was quiet. Region 9122 decayed slowly and was mostly quiet. Region 9123 was quiet and stable. New region 9124 rotated into view at the southeast limb, it appears to be old region 9087. New region 9125 rotated into view at the northeast limb. A new region developed early in the day in the southeast quadrant at a high latitude. For reasons unknown SEC/NOAA failed to number this region (which has a couple of spots). Flares and CMEs A total of 2 C class events were recorded on August 10. Region 9110 produced a C2.6/1F long duration event peaking at 03:54 UTC. 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 or 14. August 9: A fairly extensive filament eruption was observed from 16:00 UTC, the eruption occurred in the northern hemisphere and spanned an area from near the solar equator northwards to region 9122, then westwards until in the vicinity of region 9114. A clear full halo CME was observed in LASCO C3 images following this eruption. A terrestrial impact will occur, probably on August 12, and cause the geomagnetic field to range from unsettled to major storming. The background x-ray flux is at the class B9 level. Coronal holes A small coronal hole in the southern hemisphere will rotate into 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 major storm on August 11-13 due to CME activity, both in progress and expected to impact Earth during the period. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor to 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 no. Location at region numbered sunspots midnight Area Classification Comment 9110 20000731 4 S18W73 0050 CAO 9114 20000802 19 N11W29 0300 EAI beta-gamma 9115 20000803 5 N18W12 0110 CAO 9116 20000804 S12W15 plage 9117 20000805 S10W77 plage 9118 20000805 N18W67 plage 9119 20000805 4 S14W60 0030 CSO 9120 20000806 S22W30 plage 9121 20000806 2 S34W23 0060 DSO 9122 20000807 9 N21E08 0100 DSO 9123 20000808 2 N18E47 0050 DSO 9124 20000810 3 S13E64 0030 CRO 9125 20000810 3 N26E69 0040 CRO Total number of sunspots: 51 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 2000.08 163.3 (1) 51.3 (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]