Solar Terrestrial Activity Report [Image] Last update July 30, 2001 at 03:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update July 2, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update July 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to unsettled on July 29. Solar wind speed ranged between 317 and 360 km/sec. Solar flare activity was low. Solar flux was 116.9, the planetary A index was 8 (3-hour K indices: 1232 3322, Boulder K indices: 1332 2221). Region 9553 decayed further and was spotless by the end of the day. Region 9557 developed slowly and was mostly quiet. Region 9559 was mostly unchanged but seems to be decaying early on July 30. New region 9560 emerged briefly in the northeast quadrant, it was spotless late in the day. Spotted regions are rotating into view at the northeast and southeast limbs. Flares and CMEs A total of 4 C class events were recorded on July 29. Region 9557 produced a C1.1 flare at 06:21 UTC. A filament located in the northwest quadrant of the solar disk and fairly near the center of the disk disappeared during the day. Because of problems with the SOHO spacecraft it is difficult to tell whether or not a geoeffective CME was produced. If there was a CME it could reach Earth on August 1. The background x-ray flux is at the class B2-B3 level. Coronal holes A small coronal hole in the southern hemisphere was in a geoeffective position on July 27 and could cause a brief enhancement in geomagnetic activity on July 30. Forecast The geomagnetic field is expected to be quiet to unsettled on July 30, possibly with isolated active intervals due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 at region numbered sunspots midnight Area Classification Comment 9549 2001.07.18 S05W88 plage 9552 2001.07.23 N13W63 plage 9553 2001.07.23 3 N14W46 0010 BXO 9555 2001.07.24 S09W12 plage 9557 2001.07.26 9 S20E36 0130 FAO 9558 2001.07.26 N18W69 plage 9559 2001.07.27 6 S24W14 0040 DRO 9560 2001.07.29 1 N18E46 0010 AXX Total number of sunspots: 19 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 (+3.1) 2000.04 184.2 125.5 120.8 (+0.9) cycle 23 sunspot max. 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 170.1 119.7 (+1.0) 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.2 (-2.4) 2000.10 167.4 99.4 114.5 (-1.7) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 (109.6 predicted, -2.5) 2001.02 146.6 80.6 (104.8 predicted, -4.8) 2001.03 177.7 113.5 (101.2 predicted, -3.6) 2001.04 177.7 108.2 (100.0 predicted, -1.2) 2001.05 147.1 97.3 (99.3 predicted, -0.7) 2001.06 173.0 134.0 (96.6 predicted, -2.7) 2001.07 132.4 (1) 119.8 (2) (94.7 predicted, -1.9) 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 25-40% 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. ------------------------------------------------------------------------ Do you know about the survey which will be held this Summer among the listeners of WWV and WWVH? There is information about this survey at 16 minutes past the hour on WWV and at 47 minutes past the hour on WWVH. If you want to participate send an email with your name and address. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]