Solar Terrestrial Activity Report [Image] Last update April 7, 2002 at 03:45 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update April 2, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update April 2, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update April, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet on April 6. Solar wind speed ranged between 327 and 432 km/sec. Solar flare activity was low. Solar flux was 206.3, the planetary A index was 5 (3-hour K indices: 2102 2222, Boulder K indices: 2101 2212). Region 9884 rotated quietly out of view at the southwest limb. Region 9885 decayed further losing several spots in the intermediate spots section. The region was quiet. Region 9886 decayed significantly losing much of the penumbral coverage in the trailing spots section. Region 9887 decayed slowly losing penumbral area in both the leading and trailing spots section. The region was mostly quiet, a minor M class flare is still possible. Region 9888 was quiet and stable. Region 9892 was quiet and stable. Region 9893 simplified and lost a significant amount of penumbral area in the trailing spots section. There is a minor chance of a small M class flare from this region. Region 9894 decayed and was spotless by late afternoon. Region 9895 decayed into spotless plage. Region 9896 was quiet and stable. New region 9897 emerged near the center of the solar disk and initially developed quickly, only slow development has been observed since noon on April 6. New region 9898 rotated into view at the southeast limb. New region 9899 rotated into view at the northeast limb. Early on April 7 a new region is emerging quickly in the southeast quadrant. Flares and CMEs A total of 7 C class events were recorded on April 6. A C9.5 flare was observed at 06:19 UTC from a spotless area at the southeast limb. Region 9887 produced a C2.6 flare at 14:10 UTC. Region 9893 generated a C1.2 flare at 16:!7 and a C2.0 flare at 19:55 UTC. The background x-ray flux is at the class C1 level. Coronal holes A small coronal hole in the southern hemisphere was in a geoeffective position on April 5 and could cause a minor increase in geomagnetic activity late on April 8. Forecast The geomagnetic field is expected to be quiet to unsettled on April 7-9. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 region numbered sunspots at Area Classification Comment midnight 9884 2002.03.27 3 S17W90 0030 BXO 9885 2002.03.27 15 N13W64 0320 EAI 9886 2002.03.29 16 N14W51 0120 DAO 9887 2002.03.29 28 N03W42 0630 EKI 9888 2002.03.29 5 S12W32 0140 CKO 9889 2002.03.31 S20W32 plage 9891 2002.04.02 S08W61 plage 9892 2002.04.02 2 N05E07 0010 AXX 9893 2002.04.03 21 N19E40 0370 EKI beta-gamma 9894 2002.04.05 2 N14W22 0010 HRX now spotless 9895 2002.04.05 3 N06E45 0020 BXO now spotless 9896 2002.04.05 1 S11E61 0110 HSX 9897 2002.04.06 5 S01W02 0050 DAO 9898 2002.04.06 2 S19E66 0040 DAO 9899 2002.04.06 1 N18E72 0160 HAX Total number of sunspots: 100 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.02 146.6 80.6 104.0 (-4.7) 2001.03 177.7 113.5 104.8 (+0.8) 2001.04 177.7 107.7 107.5 (+2.7) 2001.05 147.1 96.6 108.6 (+1.1) 2001.06 173.0 134.0 109.8 (+1.2) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 (112.7 predicted, -1.4) 2001.11 210.6 106.5 (111.5 predicted, -1.2) 2001.12 235.1 132.2 (108.1 predicted, -3.4) 2002.01 226.6 113.9 (104.8 predicted, -3.3) 2002.02 205.0 108.0 (103.4 predicted, -1.4) 2002.03 179.5 98.1 (99.1 predicted, -4.3) 2002.04 210.4 (1) 40.8 (2) (93.2 predicted, -5.9) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]