Solar Terrestrial Activity Report [Image] Last update August 18, 2002 at 04:40 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 7, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 7, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 7, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update August 16, 2002)] Recent development The geomagnetic field was quiet to active on August 17. Solar wind speed ranged between 411 and 569 km/sec under the decreasing influence of a coronal stream. Solar flare activity was moderate. Solar flux was 226.7, the planetary A index was 13 (3-hour planetary K indices: 2343 2233, Boulder K indices: 2342 2223). Region 10063 was quiet and stable. Region 10066 was mostly unchanged and quiet. Region 10067 decayed further and was quiet. Region 10068 decayed slowly and appears to be losing its trailing spots. Region 10069 developed slowly with most of the development occurring in the northwestern part of the region. A strong magnetic delta is still present in the center of the region and there are two or three smaller deltas as well. An X10+ class proton flare is still a possibility. The region only needs to grow a little more to become the largest region observed in cycle 23. Region 10076 was quiet and stable. Region 10078 decayed quickly and had lost all spots by early evening. Region 10079 developed fairly quickly and could produce minor M class flares. Some polarity intermixing is evident in the central part of the region. Region 10080 decayed slowly and quietly. Region 10081 decayed slowly and could become spotless later today or tomorrow. New region 10082 emerged in the northeast quadrant on August 16 and was numbered by SEC/NOAA one day later. New region 10083 rotated into view at the southeast limb. Early on August 18 another region is rotating into view at the southeast limb. Flares and CMEs A total of 14 C and 2 M class events was recorded on August 17. Region 10069 produced a C4.1 flare at 00:14, a C3.2 flare at 05:05, a C4.3/1N flare at 06:27, a C4.6 flare at 06:33, a C5.0 flare at 06:57, a C2.1 flare at 08:58, a C2.5 flare at 09:11, a C3.6 flare at 14:11, a C4.1 flare at 14:27, a C4.9 flare at 15:13, a C4.8 flare at 15:38 and an impulsive M3.4 flare at 20:51 UTC. Region 10083 appears to have been the source of an M1.1 flare at 01:08 UTC. August 16: Region 10069 was the source of a major M5.2 long duration event peaking at 12:32 UTC. A strong type II radio sweep was recorded and a fast full halo CME was observed in LASCO C3 within an hour after the event. A direct impact on Earth is expected sometime during the first half of August 18. Active to major geomagnetic storming is likely for 12-24 hours after the arrival of this solar storm. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to major storm on August 18. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 10063 2002.08.06 1 N18W62 0070 HSX 10065 2002.08.08 S07W65 plage 10066 2002.08.09 13 N13W36 0050 DSO 10067 2002.08.10 28 N12W20 0160 EAI area too large 10068 2002.08.10 6 S08W20 0040 ESO 10069 2002.08.11 58 S07W03 1950 EKC beta-gamma-delta 10070 2002.08.11 N08W81 plage 10073 2002.08.12 N16W78 plage 10074 2002.08.12 N24W66 plage 10075 2002.08.12 S11W37 plage 10076 2002.08.12 1 N12E11 0020 HSX 10077 2002.08.13 S18E09 plage 10078 2002.08.14 2 S14W53 0060 CRO now spotless beta-gamma 10079 2002.08.14 23 S21E18 0150 DAO area much too small, should be near 0300 10080 2002.08.14 11 N16E30 0140 DAO 10081 2002.08.16 2 N17E47 0020 HRX 10082 2002.08.17 2 N21E06 0020 HRX 10083 2002.08.17 2 S18E67 0050 CAO Total number of sunspots: 149 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 2001.07 131.3 81.8 111.7 (+1.9) 2001.08 162.9 106.4 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 115.5 (+1.5) 2001.12 235.1 132.2 114.6 (-0.9) 2002.01 226.6 114.1 113.5 (-1.1) 2002.02 205.0 107.4 (114.0 predicted, -0.5) 2002.03 179.5 98.4 (110.3 predicted, -3.7) 2002.04 189.8 120.4 (104.5 predicted, -5.8) 2002.05 178.4 120.8 (100.0 predicted, -4.5) 2002.06 148.7 88.5 (95.5 predicted, -4.5) 2002.07 173.5 99.9 (90.6 predicted, -4.9) 2002.08 173.2 (1) 110.2 (2) (86.6 predicted, -4.0) 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]