Solar Terrestrial Activity Report [Image] Last update April 3, 2002 at 03:35 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 generally unsettled on April 3 with a single slightly active interval 03-06h UTC. Solar wind speed ranged between 491 and 644 km/sec under the decreasing influence of a high speed solar coronal stream. Solar flare activity was low. Solar flux was 209.4, the planetary A index was 13 (3-hour K indices: 3433 3333, Boulder K indices: 3423 3222). Region 9884 decayed slowly and quietly. Region 9885 decayed slowly in the trailing spots section. The region was quiet but still has minor M class flare potential. Region 9886 decayed slowly and quietly. Region 9887 did not change much and remains capable of producing a major flare. Region 9888 decayed losing more spots in the trailing section. A minor M class flare is still possible. Region 9889 decayed and was spotless by early evening. Region 9891 was quiet and stable, the region could soon become spotless. Region 9892 decayed slowly and quietly. New region 9893 rotated into view at the northeast limb. Flares and CMEs A total of 5 C class events were recorded on April 3. Region 9887 produced a C1.8 flare at 05:34. Region 9888 generated a C1.3 flare at 11:33 and a C2.8 flare at 14:24 UTC. The background x-ray flux is at the class C1 level. Coronal holes A small coronal hole in the southern hemisphere may have been in a geoeffective position on April 2 and could cause a minor increase in geomagnetic activity on April 5. Forecast The geomagnetic field is expected to be mostly quiet to unsettled on April 4-6. 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 region numbered sunspots at Area Classification Comment midnight 9883 2002.03.23 N07W75 plage 9884 2002.03.27 1 S17W53 0040 HAX 9885 2002.03.27 17 N13W26 0500 EKO 9886 2002.03.29 9 N12W10 0110 DSO beta-gamma 9887 2002.03.29 22 N02W02 0710 EKI beta-gamma 9888 2002.03.29 13 S13E07 0250 DHO 9889 2002.03.31 2 S19E05 0000 BXO now spotless 9890 2002.04.02 S15W62 plage 9891 2002.04.02 3 S08W22 0010 BXO 9892 2002.04.02 4 N04E49 0040 CSO 9893 2002.04.03 1 N18E78 0030 HSX Total number of sunspots: 72 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) 2002.04 207.5 (1) 20.4 (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]