Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 4, 2000 at 04:10 UTC. Last minor update posted at 13:28 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update February 3, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 3, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 3, 2000)] [Historical solar and geomagnetic data charts 1954-1999] [Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet to unsettled on February 3. Solar wind speed ranged between 417 and 471 km/sec. Solar flare activity was low. Solar flux was 154.1, the planetary A index was 8 (3-hour Kp indices: 1132 2233, Boulder K indices: 1132 2322). Regions 8841 and 8845 rotated off the visible disk. Region 8848 was mostly quiet and stable until near the end of the day when the region became more active. Region 8851 was quiet and stable. The region could produce occasional C flares. Region 8852 decayed into spotless plage. Region 8853 was quiet and stable, as were regions 8854 and 8855. Region 8856 was quiet and stable but could produce occasional minor M flares. New region 8857 emerged in the southeast quadrant near the central meridian. New region 8858 rotated partly into view at the northeast limb. This region is quite active and may be capable of M class flaring. New region 8859 emerged in the northwest quadrant. Comment added at 09:25 UTC on February 4: An impulsive M3.0 flare was observed at 09:21 UTC. Its origin is not yet certain, but is likely to be either of regions 8848, 8851 or 8858. Another update will be posted when further details become known. Comment added at 13:28 UTC: Although solar images at the time of the M flare at 09:19 UTC have not been available, region 8858 did display a bright post flare loop less than an hour after the flare. It's likely that this region is the source of the M flare and some of the numerous C flares observed today. Given the current flare frequency further M flares are likely and there is a minor chance of a major flare. Flares and CMEs 7 C flares were recorded on February 3. Region 8858 was (judging from LASCO-EIT images) the likely source of the largest flare of the day, a C8.4 event at 20:00 UTC. The background x-ray flux is at the class B6 level. Coronal holes A trans equatorial coronal hole was in a geoeffective position on February 2-4. Forecast The geomagnetic field is expected to be quiet to unsettled on February 4-5. Unsettled to active is likely on February 6-7 due to a coronal stream. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally fair to 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 8841 20000121 1 S32W96 0050 HSX 8846 20000126 N37W53 plage 8848 20000126 6 S08W29 0090 CSO 8849 20000128 S17W58 plage 8850 20000130 S17W28 plage 8851 20000130 19 N26W10 0120 DSO 8852 20000131 N10W25 plage 8853 20000201 3 S11E41 0020 BXO 8854 20000201 5 S34E59 0100 CAO 8855 20000202 2 N17E41 0000 BXO 8856 20000202 3 S13E69 0180 ESO 8857 20000203 4 S19E04 0010 BXO 8858 20000203 1 N24E72 0030 HRX 8859 20000203 5 N22W51 0040 CRO Total number of sunspots: 49 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.01 140.6 62.0 82.6 (+4.7) 1999.02 141.9 66.3 84.6 (+2.0) 1999.03 126.3 68.8 83.8 (-0.8) 1999.04 117.2 63.7 85.4 (+1.6) 1999.05 148.4 106.4 90.4 (+5.0) 1999.06 169.8 137.7 93.0 (+2.6) 1999.07 165.6 113.5 94.4 (+1.4) 1999.08 170.7 93.7 (97.4 predicted, +3.0) 1999.09 135.7 70.9 (102.4 predicted, +5.0) 1999.10 164.8 116.4 (107.5 predicted, +5.1) 1999.11 191.5 132.7 1999.12 169.8 86.4 2000.01 158.1 90.2 2000.02 145.5 (1) 13.2 (2) 1) Running average based on the daily 20:00 UTC solar flux measurement at 2800 MHz by DRAO. 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]