Solar Terrestrial Activity Report [Image] Last update April 30, 2002 at 02:50 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 unsettled on April 29. Solar wind speed ranged between 428 and 576 km/sec. The coronal stream which had been in progress since April 27 continued to weaken early in the day. A second coronal stream (originating from a northern hemisphere coronal hole) began to dominate by 08h UTC and solar wind speed gradually increased during the remainder of the day. Solar flare activity was low. Solar flux was 153.0, the planetary A index was 9 (3-hour K indices: 2123 3332, Boulder K indices: 1112 3321). Region 9914 decayed slowly and was mostly, the region appears to be losing its trailing spots. Region 9915 decayed further with a significant drop in penumbral area outside of the main penumbra. Region 9916 was spotless all day in all available images but was nevertheless reported by SEC/NOAA as having 4 spots. IPS in Learmonth (Australia) has reported this region as spotless the last couple of days. Region 9919 decayed slowly and quietly. Region 9921 decayed and was spotless by late afternoon. Region 9922 decayed and was spotless by midnight. Region 9926 did not change much and was quiet. New region 9927 rotated into view at the southeast limb. New region 9928 rotated into view at the northeast limb. Early on April 30 a new region is emerging in the northeast quadrant. A small region in the southeast quadrant appears to be reemerging as well having been spotted briefly in the morning on April 29. Flares and CMEs A total of 6 C class events were recorded on April 29. Region 9915 produced a C2.7 flare at 20:15 UTC. A C2.2 flare was noted at 05:37 UTC from a location near the west limb and the equator. Region 9919 was the source of a C3.4 flare at 09:28, a C4.8 flare at 09:40 and a C4.1 flare at 10:58 UTC. The background x-ray flux is at the class B7 level. Coronal holes A 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 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 3 N06W64 0160 DAO 9915 2002.04.21 9 N12W53 0200 DAI 9916 2002.04.21 4 S15W30 0030 CSO actually spotless 9917 2002.04.22 S30W46 plage 9919 2002.04.22 7 N15W13 0090 CSO 9920 2002.04.23 S20W78 plage 9921 2002.04.23 2 N14W41 0010 CRO now spotless 9922 2002.04.23 2 N22W24 0020 AXX now spotless 9924 2002.04.24 S15W77 plage 9926 2002.04.27 3 N14W01 0080 CAO 9927 2002.04.29 2 S28E68 0070 HSX 9928 2002.04.29 2 N18E75 0130 HAX Total number of sunspots: 34 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) 2002.04 191.1 (1) 191.2 (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]