Solar Terrestrial Activity Report [Image] Last update July 31, 2002 at 05:10 UTC. Daily updates will resume on August 3. [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 unsettled on July 30. Solar wind speed ranged between 371 and 486 km/sec. Solar flare activity was low. Solar flux was 227.2, the planetary A index was 8 (3-hour planetary K indices: 2212 2333, Boulder K indices: 2321 2323). Region 10039 decayed substantially and lost penumbral area both in the leading and trailing spot sections. No magnetic delta structure was observed early on August 31 as the huge leading penumbra has split into smaller penumbrae. Although the region still has the potential to produce M class flares, such flares are expected to be significantly less intense than was likely just a day ago. The major negative polarity areas in regions 10039 and 10044 appear to be merging. The regions are much more difficult to separate in magnetograms than in spot drawings. Region 10042 reemerged briefly and is spotless early on July 31. Region 10043 decayed significantly and was quiet. Region 10044 decayed in the leading and trailing spot sections but developed slowly in the intermediate spot section. M class flares are possible. Region 10048 decayed further and could become spotless late today or tomorrow. Region 10050 developed slowly and is the largest region on the visible disk early on July 31. M class flares are possible. The main positive and negative polarity areas have separated slowly and the region is magnetically not as complex as it was two days ago. Region 10051 was quiet and stable. Region 10053 decayed and was spotless by early evening. Region 10054 decayed slowly and quietly. Region 10055 developed slowly and quietly. Flares and CMEs A total of 5 C class events was recorded on July 30. Region 10039 produced a C3.3 flare at 05:30 and a C3.4 flare at 07:22 UTC. July 29: A long duration M4.7 event peaking at 10:44 UTC and originating in region 10039 may have produced a geoeffective CME which could reach Earth sometime between late on July 31 and noon on August 1. An M4.8 event earlier in the day from the some region was associated with a strong type II radio sweep and possibly a faint geoeffective CME. The background x-ray flux is at the class C1 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a possibly geoeffective position on August 1-2. Forecast The geomagnetic field is expected to be quiet to unsettled on July 31 and quiet to minor storm on August 1. The CME mentioned above could even reach Earth late on July 31. 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 no. Location region numbered sunspots at Area Classification Comment midnight 10038 2002.07.21 N18W68 plage 10039 2002.07.22 63 S14W30 0620 FKI beta-gamma 10041 2002.07.22 N16W84 plage 10042 2002.07.22 1 S22W64 0010 AXX now spotless 10043 2002.07.23 23 N12W39 0100 DSI 10044 2002.07.23 54 S20W33 0380 FKI beta-gamma 10045 2002.07.24 N06W66 plage 10046 2002.07.24 N15W56 plage 10048 2002.07.26 8 N21E00 0040 DRO 10049 2002.07.26 S05W83 plage 10050 2002.07.26 37 S08W19 0540 EKI beta-gamma 10051 2002.07.27 1 S16E28 0090 HSX 10052 2002.07.28 N09W11 plage 10053 2002.07.28 2 S17W02 0020 CSO 10054 2002.07.28 4 S22E42 0030 DRO 10055 2002.07.29 4 N14E64 0040 DRO Total number of sunspots: 197 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) 2002.07 172.3 (1) 174.7 (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]