Last major update issued on December 8, 2011 at 05:55 UTC.
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The geomagnetic field was very quiet on December 7. Solar wind speed ranged between 270 and 332 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 148.9 (decreasing 29.7 over the last solar rotation). The planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.4). Three hour interval K indices: 00010101 (planetary), 00000111 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight UTC the visible solar disk had 21 spotted regions (in 2K resolution SDO images).
Region 11362 [N08W61] decayed slowly and lost all penumbra on the
trailing spots.
Region 11363 [S17W37] was quiet and stable.
Region 11364 [N19W29] developed as new flux emerged near the largest
penumbra. Flare: C1.3 at 15:39 UTC
Region 11365 [N19W49] decayed and could soon become spotless.
Region 11366 [N18E13] was quiet and stable.
Region 11367 [S17W03] decayed slowly and quietly.
Region 11368 [S15E27] decayed slowly and quietly.
Region 11369 [N22E17] decayed slowly and quietly.
New region 11370 [S25W03] emerged in the southeast quadrant on December 5
and was numbered by SWPC 2 days later. The region decayed slowly on Dec.7.
New region 11371 [N10E14] emerged in the northeast quadrant on December 4
and was noticed by SWPC 3 days later. Slow decay was observed on Dec.7.
New region 11372 [N08E32] emerged in the northeast quadrant on December 6
and got an SWPC number the next day.
Spotted regions not reported by NOAA/SWPC:
[S1342] rotated into view at the southeast limb on Nov.28. The region
developed quickly on Dec.1-3 while the region has decayed moderately quickly
since December 4. Location at midnight: S22W33.
[S1349] was split off from 11366 on December 4. Location at midnight:
N28E14
[S1353] emerged in the northeast quadrant on December 4. Location at
midnight: N14E25
[S1355] emerged in the northeast quadrant on December 5. Location at
midnight: N23W06
[S1358] rotated into view at the southeast limb on December 7. Location at midnight:
S17E81
[S1359] emerged in the southwest quadrant on December 7. Location at
midnight: S29W24
[S1360] emerged in the northwest quadrant on December 7. Location at
midnight: N17W65
[S1361] emerged in the northeast quadrant on December 7. Location at
midnight: N30E45
[S1362] emerged in the southeast quadrant on December 7. Location at
midnight: S20E32
[S1363] emerged in the southeast quadrant on December 7. Location at
midnight: S14E05
December 5-7: No obviously Earth directed CMEs observed.
Coronal hole history (since late October
2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago
A small coronal hole (CH487) in the northern hemisphere will be in an Earth facing position on December 7-8.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, 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 the new method, the extent and intensity of both holes 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 fair to good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on December 8-10. On December 11-12 there's a chance of a few unsettled and active intervals due to effects from CH487.
| Coronal holes (1) | Coronal mass ejections (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
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 | |||||
| 11362 | 2011.11.27 | 3 | 7 | N06W59 | 0180 | ESO | CSO |
 |
 |
area: 0080 location: N08W61 |
| 11363 | 2011.11.28 2011.11.29 |
12 | 1 | S22W32 | 0400 | EHI | HAX |
 |
 |
location: S17W37 area: 0050 SWPC includes S1342 in this region |
| 11364 | 2011.11.28 2011.11.29 |
1 | 7 | N18W30 | 0060 | HSX | DSO |
 |
 |
area: 0120 |
| S1342 | 2011.11.28 | 14 | S22W33 | 0550 | DHO |
 |
 |
|||
| S1343 | 2011.11.29 | S12W56 |
 |
plage | ||||||
| 11365 | 2011.12.01 2011.12.02 |
1 | 1 | N17W48 | 0010 | AXX | AXX |
 |
 |
|
| 11366 | 2011.12.02 2011.12.03 |
2 | 5 | N17E13 | 0070 | CSO | HSX |
 |
 |
area: 0110 |
| 11367 | 2011.12.04 | 4 | 4 | S26W03 | 0010 | BXO | BXO |
 |
 |
location: S17W03 |
| S1349 | 2011.12.04 | 4 | N28E14 | 0000 | BXO |
 |
 |
|||
| 11369 | 2011.12.04 2011.12.05 |
1 | N22E15 | 0010 | AXX |
 |
 |
location: N22E17 | ||
| 11371 | 2011.12.04 2011.12.07 |
1 | 3 | N09E13 | 0010 | HRX | AXX |
 |
 |
location: N10E14 |
| S1352 | 2011.12.04 | N10W54 | plage | |||||||
| S1353 | 2011.12.04 | 1 | N14E25 | 0000 | AXX |
 |
 |
|||
| 11368 | 2011.12.05 | 1 | S16E27 | 0000 | AXX |
 |
 |
|||
| 11370 | 2011.12.05 2011.12.07 |
6 | 6 | S24W03 | 0010 | BXO | CRO |
 |
 |
|
| S1355 | 2011.12.05 | 1 | N23W06 | 0000 | AXX |
 |
 |
|||
| S1356 | 2011.12.05 | S16W21 | plage | |||||||
| 11372 | 2011.12.06 2011.12.07 |
2 | 4 | N10E28 | 0000 | BXO | BXO |
 |
 |
|
| S1358 | 2011.12.07 | 1 | S17E81 | 0350 | HHX |
 |
||||
| S1359 | 2011.12.07 | 2 | S29W24 | 0020 | CRO |
 |
||||
| S1360 | 2011.12.07 | 4 | N17W65 | 0050 | DAO |
 |
||||
| S1361 | 2011.12.07 | 1 | N30E45 | 0000 | AXX |
 |
||||
| S1362 | 2011.12.07 | 1 | S20E32 | 0000 | AXX |
 |
||||
| S1363 | 2011.12.07 | 3 | S14E05 | 0000 | AXX |
 |
||||
| Total spot count: | 32 | 72 | ||||||||
| Sunspot number: | 122 | 282 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted penumbral SN: | 60 | 123 | (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): | 73 | 127 | k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1) for STAR SDO | |||||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 2010.10 | 81.6 | 23.5 | 23.2 (+3.6) | 6.07 / 6.27 |
| 2010.11 | 82.5 | 21.5 | 26.5 (+3.3) | 4.80 / 5.50 |
| 2010.12 | 84.2 | 14.4 | 28.8 (+2.3) | 3.41 / 4.35 |
| 2011.01 | 83.6 | 19.1 | 31.0 (+2.2) | 4.32 / 5.51 |
| 2011.02 | 94.6 | 29.4 | 33.4 (+2.4) | 5.41 / 6.44 |
| 2011.03 | 115.0 | 56.2 | 36.9 (+3.5) | 7.79 / 8.18 |
| 2011.04 | 112.6 | 54.4 | 41.8 (+4.9) | 9.71 / 8.83 |
| 2011.05 | 95.8 | 41.6 | 47.6 (+5.8) | 9.18 / 8.94 |
| 2011.06 | 95.8 | 37.0 | (53.7 projected, +6.1) | 8.96 / 8.06 |
| 2011.07 | 94.2 | 43.9 | (60.0 projected, +6.3) | 9.14 / 8.16 |
| 2011.08 | 101.7 | 50.6 | (65.5 projected, +5.5) | 8.16 / 7.26 |
| 2011.09 | 133.8 | 78.0 | (68.8 projected, +3.3) | 12.80 / 12.27 |
| 2011.10 | 137.3 | 88.0 | (72.3 projected, +3.5) | 7.52 |
| 2011.11 | 153.5 | 96.7 | (76.6 projected, +4.3) | 4.58 |
| 2011.12 | 155.9 (1) | 30.2 (2A) / 133.9 (2B) | (82.1 projected, +5.5) | (4.18) |
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 preliminary daily SWPC ap indices.
Values in red are based on the official NGDC
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.
