Solar Terrestrial Activity Report [Image] Last update July 29, 2002 at 05:50 UTC. Only occasional updates will be posted until August 3 due to vacation. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update July 1, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update July 1, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update July 1, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to active on July 28. Solar wind speed ranged between 436 and 534 km/sec. Solar flare activity was moderate. Solar flux was 238.8, the planetary A index was 12 (3-hour planetary K indices: 4323 3332, Boulder K indices: 3322 2322). Region 10037 was quiet and stable and rotated over the northwest limb early on July 29. Region 10038 decayed slowly and quietly and could become spotless later today. Region 10039 decayed losing penumbral area both in the leading and trailing spot sections. Some development was observed in the intermediate spot section. The region still has a magnetic delta in the large leading penumbra and one in the easternmost trailing penumbra. The region has not produced a large flare since July 23 and it is difficult to tell if and when another major flare could occur. The potential for such a flare still exists. It should be noted that the general layout of regions 10039 and 10044 has changed over the last few days. The trailing part of region 10044 now appears to be part of region 10039 as the southern positive polarity field is slowly sliding eastwards compared to the main negative field. Region 10042 decayed and was spotless by the end of the day. Region 10043 developed slowly and added penumbral area in both the leading and intermediate spot sections. Region 10044 decayed further losing penumbral area in all parts of the region. The trailing section of this region cannot anymore be separated from region 10039. A magnetic delta structure exists in the intermediate spot section. Further M class flares are possible. Region 10045 decayed quickly and could become spotless later today or tomorrow if the current rate of decay continues. Region 10048 decayed slowly and quietly. Region 10050 developed further and has M class flare potential. The penumbral area more than doubled and a magnetic delta structure is developing in the center of the region. Region 10051 was quiet and stable. New region 10052 in the northeast quadrant emerged on July 27 and was finally numbered by SEC/NOAA. The region decayed slowly all day and could soon become spotless. New region 10053 emerged in the southeast quadrant on July 27 and decayed slowly. New region 10054 rotated into view at the southeast limb. Flares and CMEs A total of 14 C and 2 M class events was recorded on July 28. Region 10044 produced an M2.5/1N flare at 00:30 UTC. LASCO C3 images hint at a weak halo CME associated with this event. The region was the source of a C3.6 flare at 05:58 and a C3.6 flare at 08:44 UTC. Region 10039 generated a C2.5 flare at 06:40, a C7.6 flare at 11:06 and a C2.3 flare at 15:00 UTC. Region 10050 produced a C2.2 flare at 10:49 UTC. Region 10043 was the source of a C5.1 flare at 20:50 UTC. An M4.8/1F flare at 02:38 UTC on July 29 appears to have had its origin in region 10044 and was associated with a type II sweep and a CME which is likely to be geoeffective. The CME so far appears to be fairly small. July 26: A long duration major M5.3 long duration event peaking at 22:13 UTC. Its origin appear to have been in the area separating regions 10039 and 10044. The LDE was associated with a full halo CME. This CME will impact Earth, most likely during the first half of July 29, and could cause active to major geomagnetic storm conditions. The background x-ray flux is at the class C2 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a possibly geoeffective position on August 2. Forecast The geomagnetic field is expected to be quiet to major storm on July 29 and quiet to active on July 30-31. 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 10037 2002.07.17 1 N13W87 0090 HSX 10038 2002.07.21 3 N18W44 0020 CSO 10039 2002.07.22 48 S15W04 0920 FKI beta-gamma-delta area too large 10040 2002.07.22 S19W82 plage 10041 2002.07.22 N16W58 plage 10042 2002.07.22 1 S19W43 0010 HRX now spotless 10043 2002.07.23 20 N12W13 0160 DAI area too small 10044 2002.07.23 43 S21W11 0530 FKI beta-gamma-delta 10045 2002.07.24 12 N05W39 0110 DAO area too large 10046 2002.07.24 N15W30 plage 10047 2002.07.25 N09W87 plage 10048 2002.07.26 10 N21E25 0100 DSO area estimate way too large 10049 2002.07.26 S05W57 plage beta-gamma-delta 10050 2002.07.26 23 S07E09 0290 DAO area too low, was approaching 0500 at midnight 10051 2002.07.27 1 S16E54 0100 HSX 10052 2002.07.28 5 N09E17 0030 CRO 10053 2002.07.28 1 S17E24 0010 HRX 10054 2002.07.28 2 S21E70 0040 CRO Total number of sunspots: 180 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 2001.06 173.0 134.0 109.8 (+1.2) 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 (112.7 predicted, -1.9) 2002.02 205.0 107.4 (111.3 predicted, -1.4) 2002.03 179.5 98.4 (106.6 predicted, -4.7) 2002.04 189.8 120.4 (100.7 predicted, -5.9) 2002.05 178.4 120.8 (96.3 predicted, -4.4) 2002.06 148.7 88.5 (91.7 predicted, -4.6) 2002.07 168.1 (1) 155.3 (2) (86.9 predicted, -4.8) 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]