Solar Terrestrial Activity Report [Image] Last update July 29, 2001 at 05:15 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 on July 28. Solar wind speed ranged between 351 and 448 km/sec. Solar flare activity was low. Solar flux was 115.5 (the lowest solar flux at 20h UTC since September 1999. Since November 1998 only two months have had a lower solar flux average than July), the planetary A index was 5 (3-hour K indices: 2002 2222, Boulder K indices: 2001 2212). Region 9543 rotated off the visible disk early in the day. Region 9548 was quiet and stable and will rotate over the west limb on July 29. Region 9553 decayed very quickly with no penumbra observed by midnight. The region could become spotless today. Region 9555 reemerged for a few hours with a single spot. Region 9557 developed slowly and was quiet. Region 9559 developed slowly and was quiet. Flares and CMEs A total of 2 C class events were recorded on July 28, the largest an optically uncorrelated C7.8 flare at 13:53 UTC. The background x-ray flux is at the class B2 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 mostly quiet on July 29 and 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 9543 2001.07.15 1 S23W89 0060 HSX 9548 2001.07.18 1 N17W84 0060 HSX 9549 2001.07.18 S05W75 plage 9552 2001.07.23 N13W50 plage 9553 2001.07.23 13 N13W33 0030 CRO 9555 2001.07.24 1 S09E01 0000 HRX 9556 2001.07.25 S07W82 plage 9557 2001.07.26 4 S20E48 0090 ESO 9558 2001.07.26 N18W56 plage 9559 2001.07.27 8 S24E00 0030 CRO Total number of sunspots: 28 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) 2001.07 132.9 (1) 117.9 (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]