Solar Terrestrial Activity Report [Image] Last update April 29, 2002 at 04:20 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 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to active on April 28. Solar wind speed ranged between 449 and 560 km/sec under the influence of a weakening coronal stream. Solar flare activity was low. Solar flux was 147.1 (the lowest solar flux since August 17, 2001), the planetary A index was 19 (3-hour K indices: 3444 4332, Boulder K indices: 3444 3322). Region 9914 decayed slowly and quietly. Region 9915 decayed significantly and was mostly quiet. Region 9916 decayed and was spotless early in the day (the region was still included in SEC/NOAAs spot summary with an area and spot count higher than on the previous day!). Region 9919 decayed and could produce small C flares. Region 9921 decayed and could become spotless late today. Region 9922 reemerged with a single spot and has added two more small spots as of early on April 29. Region 9926 did not change much and was quiet. Flares and CMEs A total of 3 C class events were recorded on April 28. Spotless region 9924 produced a C1.0 flare at 18:23. Region 9915 generated a C1.2 flare at 21:03 UTC. The background x-ray flux is at the class B6 level. Coronal holes A small coronal hole in the northern hemisphere was in a geoeffective position on April 27. Another, larger, and developing coronal hole in the southern hemisphere was geoeffective on April 28-29. Forecast The geomagnetic field is expected to be quiet to unsettled on April 29-30 and quiet to active May 1-2 due to coronal hole effects. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9914 2002.04.19 5 N05W51 0170 DSO 9915 2002.04.21 18 N12W40 0240 DAI area and spot count 9916 2002.04.21 7 S18W19 0030 CRO too high now spotless 9917 2002.04.22 S30W33 plage 9918 2002.04.22 N06W78 plage 9919 2002.04.22 8 N14E01 0130 DSO 9920 2002.04.23 S20W65 plage 9921 2002.04.23 5 N14W27 0050 DSO 9922 2002.04.23 1 N22W13 0010 AXX 9923 2002.04.24 S03W85 plage 9924 2002.04.24 S15W64 plage 9925 2002.04.24 S14W78 plage 9926 2002.04.27 7 N13E11 0060 DSO Total number of sunspots: 51 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 (113.3 predicted, -0.8) 2001.11 210.6 106.5 (112.7 predicted, -0.6) 2001.12 235.1 132.2 (109.3 predicted, -3.4) 2002.01 226.6 113.9 (106.0 predicted, -3.3) 2002.02 205.0 108.0 (104.6 predicted, -1.4) 2002.03 179.5 98.1 (100.4 predicted, -4.2) 2002.04 192.4 (1) 187.1 (2) (94.5 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]