Last major update issued on August 28, 2012 at 05:00 UTC.
[Solar and geomagnetic data - last month (updated
daily)]
[Solar wind and
electron fluence charts (updated
daily)]
[Solar cycles 21-24 (last update
August 6, 2012)] [Cycle
24 progress (last update August 2, 2012) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last
update August 6, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and
24 (last update August 6, 2012)]
[Historical solar and geomagnetic data charts 1954-2006
(last update April 5, 2007)]
[Archived reports since January 2003 (last update
August 5, 2012)]
[POES auroral activity level since October
2009 - updated August 5, 2012]
[Solar polar fields vs solar cycles - updated
June 27, 2011]
The geomagnetic field was quiet to unsettled on August 27. Solar wind speed at SOHO ranged between 462 and 712 km/s under the weakening influence of a high speed stream associated with CH530.
Solar flux measured at 20h UTC on 2.8 GHz was 111.5 (decreasing 28.3 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.1). Three hour interval K indices: 23210112 (planetary), 23222222 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight UTC the visible solar disk had 12 spotted active regions (in 2K resolution SDO images).
Region 11552 [S14W36] lost most of the spots with only two tiny spots
observed in the far western part of the leading polarity area.
Region 11553 [S22E08] decayed losing all trailing polarity spots.
Region 11554 [N16W28] decayed slowly and quietly.
Region 11555 [N08E44] added some spots while the trailing penumbra
fragmented.
New region 11556 [S13W80] emerged in August 26 and was numbered by SWPC
the next day as it rotated to the southwest limb.
New region 11557 [N17E38] emerged with 2 spots along a north-south axis.
New region 11558 [N17E78] rotated into view with a few small spots.
Spotted regions not numbered by NOAA/SWPC:
S1876 [N16E06] was quiet and stable.
New region S1881 [S19E35] emerged with a tiny spot.
New region S1882 [N21E65] emerged with a tiny spot.
New region S1883 [N13E72] rotated into view with two small spots.
New region S1884 [N15E56] emerged with a tiny spot.
August 25-27: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
Coronal hole history (since October
2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A small trans equatorial coronal hole (CH531) has developed over the last few days and was in an Earth facing position on August 27.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet on August 28-29 and quiet to unsettled on August 30-31 due to weak effects from CH531.
Coronal holes (1) | Coronal mass ejection (2) | M and X class flares (3) |
1) Effects from a coronal hole could reach Earth within the
next 5 days. When the high speed stream has arrived the color changes to
green.
2) Effects from a CME are likely to be observed at 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.
Click on image for higher resolution image) Compare to the previous day's image. 0.5k image [NEW]
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
Active region | Date numbered detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with magnetic polarity overlay |
Comment | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
SWPC | STAR SDO | SWPC | STAR | Current | Previous | ||||||
2K | 1K | ||||||||||
11546 | 2012.08.15 2012.08.16 |
N17W72 | plage | ||||||||
11548 | 2012.08.17 2012.08.18 |
N18W50 | plage | ||||||||
11552 | 2012.08.20 2012.08.21 |
2 | S17W21 | 0000 | AXX | location: S14W36 | |||||
11553 | 2012.08.22 2012.08.23 |
4 | 11 | 5 | S18E05 | 0120 | DSO | HSX |
area: 0200 |
||
11554 | 2012.08.23 2012.08.24 |
6 | 9 | 4 | N16W27 | 0110 | DAO | DAO | |||
11555 | 2012.08.24 2012.08.25 |
10 | 19 | 9 | N08E43 | 0320 | DHO | DAC | |||
S1875 | 2012.08.24 | N10W32 | plage | ||||||||
S1876 | 2012.08.25 | 1 | N16E06 | 0000 | AXX | ||||||
S1877 | 2012.08.25 | N12W10 | plage | ||||||||
S1878 | 2012.08.26 | N05W22 | plage | ||||||||
11556 | 2012.08.26 2012.08.27 |
1 | 2 | 1 | S12W79 | 0010 | AXX | BXO | |||
S1880 | 2012.08.26 | N28W06 | plage | ||||||||
11557 | 2012.08.27 | 2 | 2 | 2 | N17E38 | 0010 | BXO | CRO | |||
11558 | 2012.08.27 | 2 | 3 | 2 | N18E78 | 0010 | BXO | AXX | |||
S1881 | 2012.08.27 | 1 | 1 | S19E35 | 0000 | AXX | |||||
S1882 | 2012.08.27 | 1 | N21E65 | 0000 | AXX | ||||||
S1883 | 2012.08.27 | 2 | 2 | N13E72 | 0010 | AXX | |||||
S1884 | 2012.08.27 | 1 | N15E56 | 0000 | AXX | ||||||
Total spot count: | 25 | 54 | 26 | ||||||||
Sunspot number: | 85 | 174 | 106 | (total spot count + 10 * number of spotted regions) | |||||||
Weighted SN: | 45 | 72 | 44 | (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10) | |||||||
Relative sunspot number (Wolf number): | 51 | 61 | 58 | k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K |
Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
---|---|---|---|---|
2011.05 | 95.8 | 41.6 | 47.6 (+5.8) | 8.94 |
2011.06 | 95.8 | 37.0 | 53.2 (+5.6) | 8.06 |
2011.07 | 94.2 | 43.9 | 57.2 (+4.0) | 8.16 |
2011.08 | 101.7 | 50.6 | 59.0 (+1.8) | 7.26 |
2011.09 | 133.8 | 78.0 | 59.5 (+0.5) | 12.27 |
2011.10 | 137.3 | 88.0 | 59.9 (+0.4) | 8.28 |
2011.11 | 153.5 | 96.7 | 61.1 (+1.2) | 5.55 |
2011.12 | 141.3 | 73.0 | 63.4 (+2.3) | 3.78 |
2012.01 | 132.5 | 58.3 | 65.5 (+2.1) | 7.15 |
2012.02 | 106.5 | 32.9 | (67.4 projected, +1.9) | 8.81 |
2012.03 | 114.7 | 64.3 | (68.1 projected, +0.7) | 16.08 |
2012.04 | 113.0 | 55.2 | (67.5 projected, -0.6) | 10.10 |
2012.05 | 121.5 | 69.0 | (65.8 projected, -1.7) | 7.06 |
2012.06 | 119.6 | 64.5 | (65.0 projected, -0.8) | 10.08 |
2012.07 | 133.9 | 66.5 | (66.0 projected, +1.0) | 13.90 |
2012.08 | 114.4 (1) | 72.1 (2A) / 82.8 (2B) | (68.6 projected, +2.6) | (8.10) |
1) Running average based on the daily 20:00 UTC observed solar flux value at
2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder
(NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The
official SIDC international sunspot number is typically 30-50% lower. 2B) Month
average to date.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices.
Values in red are based on the definitive
international Potsdam
WDC
ap indices.
This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.