Solar Terrestrial Activity Report [Image] Last update March 27, 2001 at 04:05 UT. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update March 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 1, 2001)] [Historical solar and geomagnetic data charts 1954-2000 (last update January 18, 2001)] Recent development The geomagnetic field was quiet to unsettled on March 26. Solar wind speed ranged between 321 and 378 km/sec. A solar wind shock was observed at ACE at 01:10 on March 25. Solar wind speed increased abruptly from 350 to 440 km/sec. The source of this CME disturbance is uncertain as it probably is too early for the arrival of the halo CME observed after noon on March 25. Solar flare activity was moderate. Solar flux was 263.7 (close to the highest recorded value during cycle 23 and an increase of more than 100 in just five days), the planetary A index was 6 (3-hour K indices: 0011 3231, Boulder K indices: 1111 3331). Region 9387 decayed slowly and was quiet. Region 9389 was mostly unchanged and quiet. Region 9390 was generally unchanged and mostly quiet. Region 9392 was quiet and stable, the region is rotating off the visible disk. Region 9393 developed fairly quickly, particularly in the southwestern part of the region. This region (which early on March 27 has the largest areal coverage observed in any region during cycle 23) has a very high flare potential and could produce minor X class flares any time. An X10+ proton flare is possible as well. Region 9394 was quiet and stable, as was region 9395. Region 9396 developed further and could produce M class flares. Region 9397 was mostly quiet and stable, M class flares are possible. Region 9398 decayed slowly and was quiet. Region 9399 was unchanged and quiet. Region 9400 was quiet and stable. Region 9401 is close to region 9393 and is capable of producing a major flare. Region 9402 was quiet and stable. New region 9403 rotated into view at the southeast limb. Flares and CMEs A total of 5 C and 2 M class events were recorded on March 26. Region 9393 produced an M2.5/2N flare at 04:24 and a C3.5 flare at 22:32 UT. Region 9390 generated a C3.4 flare at 05:40 and a C4.1 flare at 20:54 UT. Region 9401 was the source of an M2.6/1N flare at 11:16 and a C9.4 flare at 20:17 UT. March 25: Region 9394 produced a C9.0/1F long duration event peaking at 16:36 UT. A full halo CME was observed in LASCO images. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to minor storm on March 27 and quiet to active on March 28. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9385 2001.03.17 S11W77 plage 9387 2001.03.19 2 N09W38 0160 CSO 9389 2001.03.20 30 S13W02 0090 FAI 9390 2001.03.20 18 N15W08 0090 ESI 9391 2001.03.21 S04W80 plage 9392 2001.03.21 1 N18W80 0060 HSX 9393 2001.03.21 61 N18E27 1100 FKC beta-gamma-delta 9394 2001.03.22 1 N09E22 0010 HSX 9395 2001.03.23 4 S12E35 0060 CSO 9396 2001.03.24 22 S06W32 0110 DAI beta-gamma 9397 2001.03.24 11 S10E47 0260 EAO 9398 2001.03.24 1 N21W26 0010 HSX 9399 2001.03.24 9 S29W22 0030 DSO 9400 2001.03.24 4 N10E05 0010 CRO 9401 2001.03.25 21 N22E43 0270 DKO beta-gamma 9402 2001.03.25 3 N16E02 0010 CRO 9403 2001.03.26 1 S13E62 0020 HRX Total number of sunspots: 189 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.8 (+3.9) 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) 2000.07 202.3 170.1 119.8 (+1.1) 2000.08 163.0 130.5 118.6 (-1.2) 2000.09 182.1 109.7 (115.4 predicted, -3.2) 2000.10 167.4 100.1 (113.0 predicted, -2.4) 2000.11 178.8 106.5 (111.0 predicted, -2.0) 2000.12 173.6 104.5 (108.5 predicted, -2.5) 2001.01 166.6 95.7 (104.7 predicted, -3.8) 2001.02 146.6 80.1 (100.3 predicted, -4.4) 2001.03 161.5 (1) 114.1 (2) (96.8 predicted, -3.5) 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]