Solar Terrestrial Activity Report [Image] Last update May 17, 2002 at 04:10 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update May 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to unsettled on May 16. Solar wind speed ranged between 341 and 397 km/sec. Solar flare activity was low. Solar flux was 158.4, the planetary A index was 12 (3-hour K indices: 3323 3333, Boulder K indices: 2322 3222). Region 9945 decayed further and was quiet. Region 9948 decayed slightly as it lost all trailing spots. A minor M class flare is possible. Region 9950 decayed and early on May 17 has just a single spot left. Region 9951 decayed and was spotless by the end of the day. Region 9953 decayed and could become spotless today. Region 9954 was quiet and stable, as was region 9955. New region 9956 emerged briefly in the southern hemisphere over the central meridian, the region is spotless early on May 17. New region 9957 rotated into view at the northeast limb. SEC/NOAA did an exceptionally poor job in not numbering the region which rotated into view early the day before ahead of (by about 10 degrees longitude) region 9957 having its own small positive and negative magnetic polarity areas. Region 9957 is a complex region with a magnetic delta structure and is capable of producing frequent M class flares. Flares and CMEs A total of 3 C class events were recorded on May 16. Region 9948 was the source of a long duration C4.5 peaking at 00:35 UTC. Type II and IV radio sweeps were recorded and a full halo CME was observed in LASCO images. The CME will likely impact the Earth sometime during the latter half of May 18 or early on May 19 and could cause unsettled to minor storm conditions. Region 9957 produced a long duration C5.0 event peaking at 05:21 UTC. This was easily observed in LASCO EIT images and differencing movies. SEC/NOAA claimed that the LDE had its origin in region 9948, even to the degree that this had been visually correlated, but the claim is not supported by other sources. Region 9945 generated a C1.7 flare at 09:43 UTC. Several interesting events have been observed early on May 17. A large filament in the southeast quadrant, just east of region 9948, began to show strong motions late on May 16 and erupted magnificently early today. The eruption was observed along a filament channel stretching south-southeastwards from near the center of the visible disk. It is likely that a large geoeffective CME has been produced but I haven't yet been able to confirm that. Region 9957 appears to have been the source of an M1.5 flare at 01:23 UTC. The background x-ray flux is at the class B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on May 16-17. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very 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 9943 2002.05.05 S10W81 plage 9944 2002.05.07 N08W82 plage 9945 2002.05.07 6 S03W54 0250 CAO 9946 2002.05.08 S06W43 plage 9948 2002.05.10 4 S22E01 0370 EKO 9949 2002.05.11 S16W74 plage 9950 2002.05.11 5 S05W23 0030 CSO 9951 2002.05.12 1 N11E14 0000 AXX now spotless 9952 2002.05.13 S15W61 plage 9953 2002.05.15 5 N06W65 0050 BXO area way too large 9954 2002.05.15 3 S22E54 0130 HAX 9955 2002.05.15 1 S14E55 0040 HSX 9956 2002.05.16 1 S08W04 0000 AXX now spotless 9957 2002.05.16 4 N06E67 0570 EKO beta-gamma-delta way too few spots Total number of sunspots: 30 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 2001.04 177.7 107.7 107.5 (+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) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 (114.7 predicted, +0.7) 2001.12 235.1 132.2 (112.5 predicted, -2.2) 2002.01 226.6 113.9 (109.8 predicted, -2.7) 2002.02 205.0 108.0 (108.4 predicted, -1.4) 2002.03 179.5 98.1 (104.2 predicted, -4.2) 2002.04 189.8 120.4 (98.3 predicted, -3.9) 2002.05 177.9 (1) 108.4 (2) (93.8 predicted, -4.5) 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]