Last major update issued on September 25, 2014 at 04:00 UTC.
[Solar and geomagnetic data - last month (updated
daily)]
[Solar wind and
electron fluence charts (updated
daily)]
[Solar cycles 23-24 (last update September 1, 2014)] [Cycle
24 progress (last update September 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last
update September 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and
24 (last update September 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006
(last update April 5, 2007)]
[Archived reports since January 2003 (last update
September 6, 2014)]
[New: Noon SDO count 1K 4K (large file)]
[POES auroral activity level October
2009 - December 2012]
[Solar polar fields vs solar cycles - updated
September 6, 2014]
[Presentations:
3rd
SSN Workshop, Tucson, 2013 (pdf)
/
4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to active on September 24. Solar wind speed at SOHO ranged between 381 and 471 km/s under the influence of medium high speed stream from CH635.
Solar flux at 20h UTC on 2.8 GHz was 145 (increasing 26.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 136.3. The Potsdam WDC planetary A index was 23 (STAR Ap - based on the mean of three hour interval ap indices: 23.4). Three hour interval K indices: 44244334 (planetary), 44354334 (Boulder).
The background x-ray flux is at the class B8 level.
At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 232) and 8 active regions using 1K resolution (SN: 152) SDO images on the visible solar disk.
Region 12169 [N05W27] was quiet and stable.
Region 12170 [N10W25] decayed quickly with the disintegration of
the largest penubra.
Region 12171 [S11W00] decayed slowly and quietly.
Region 12172 [S11E24] developed further with a weak magnetic delta
structure forming in a central penumbra. M class flares are possible.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3835 [N13E02] developed quickly during the latter half of the day with
new flux emerging and many small spots forming. The region has polarity
intermixing and could produce a minor M class flare if further development
occurs.
S3839 [N07E57] reemerged with a few spots.
New region S3843 [N11E23] emerged with penumbra spots.
New region S3844 [N17W02] emerged with penumbra spots.
New region S3845 [S24W19] emerged with a penumbra spot.
A region just behind the northeast limb was quite active during the day and may be capable of M class flaring as it rotates into view.
| Magnitude | Peak time (UTC) | Location | AR | Comment |
| C7.0/1N | 17:50 | S13E24 | 12172 | |
| C4.8 | 23:42 | NE limb |
September 22-24: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery. A large backsided northern hemisphere CME was observed late on September 24, this CME was associated with a minor enhancement in proton levels.
[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 northern hemisphere coronal hole (CH635) was in an Earth facing position on September 20 and early on Sept.21. A recurrent southern hemisphere coronal hole was in an Earth facing position on September 22-25.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair to good.
The geomagnetic field is expected to be quiet to active on September 25-28 due to coronal hole effects.
| 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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.
(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue 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 | Magnetic (SDO) |
SWPC | STAR | Current | Previous | ||||||
| 2K | 1K | ||||||||||
| 12167 | 2014.09.13 2014.09.14 |
N09W84 | plage | ||||||||
| 12169 | 2014.09.16 2014.09.17 |
1 | 8 | 3 | N05W28 | 0010 | AXX | CRO |
 |
 |
|
| 12170 | 2014.09.16 2014.09.17 |
2 | 6 | 3 | N11W26 | 0030 | HAX | HRX |
 |
 |
|
| 12168 | 2014.09.16 2014.09.17 |
S22W52 | plage | ||||||||
| 12174 | 2014.09.17 2014.09.22 |
1 | N15W95 | 0030 | HSX |
rotated out of view early on Sept.23. Major error by SWPC to include a
backsided region. Obviously not a valid observation actual location: N15W106 |
|||||
| 12171 | 2014.09.18 2014.09.19 |
6 | 21 | 10 | S10W01 | 0080 | ESO | ESO |
 |
 |
area: 0200 |
| 12173 | 2014.09.19 2014.09.20 |
S15E10 | trailing polarity area merged with AR 12172 | ||||||||
| 12172 | 2014.09.20 | 16 | 72 | 36 | S10E24 | 0440 | EKC | EKC |
 |
 |
beta-gamma-delta area: 1020 |
| S3835 | 2014.09.21 | 26 | 15 | N13E02 | 0090 | DRI |
 |
 |
|||
| S3836 | 2014.09.22 | S11W18 | plage | ||||||||
| S3837 | 2014.09.22 | N15W10 |
 |
plage | |||||||
| S3839 | 2014.09.22 | 4 | 2 | N07E57 | 0015 | CRO |
 |
||||
| S3842 | 2014.09.23 | S20W16 |
 |
plage | |||||||
| S3843 | 2014.09.24 | 2 | 2 | N11E23 | 0007 | BXO |
 |
||||
| S3844 | 2014.09.24 | 2 | 2 | N17W02 | 0007 | BXO |
|
||||
| S3845 | 2014.09.24 | 1 | S24W19 | 0002 | AXX |
 |
|||||
| Total spot count: | 26 | 142 | 73 | ||||||||
| Sunspot number: | 76 | 232 | 153 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 51 | 169 | 100 | (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): | 46 | 81 | 84 | k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number) | |||||||
| Month | Average solar flux | International sunspot number (WDC-SILSO) |
Smoothed sunspot number | Average ap (3) |
|
|---|---|---|---|---|---|
| Measured | 1 AU | ||||
| 2013.05 | 131.4 | 134.3 | 78.7 | 59.9 (+2.0) | 9.73 |
| 2013.06 | 110.1 | 113.7 | 52.5 | 62.6 (+2.7) | 12.60 |
| 2013.07 | 115.5 | 119.3 | 57.0 | 65.5 (+2.9) | 9.47 |
| 2013.08 | 114.6 | 118.3 | 66.0 | 69.0 (+3.5) | 8.27 |
| 2013.09 | 102.6 | 103.7 | 36.9 | 73.1 (+4.1) | 5.23 |
| 2013.10 | 132.1 | 131.2 | 85.6 | 75.0 (+1.9) | 7.71 |
| 2013.11 | 148.3 | 145.1 | 77.6 | 75.4 (+0.4) | 5.68 |
| 2013.12 | 147.7 | 143.1 | 90.3 | 76.0 (+0.6) | 4.68 |
| 2014.01 | 157.4 | 152.4 | 81.8 | 77.3 (+1.3) | 5.44 |
| 2014.02 | 170.3 (cycle peak) |
166.3 | 102.3 (cycle peak) | 78.4 (+1.1) | 10.70 |
| 2014.03 | 149.9 | 148.5 | 91.9 | (80.3 projected, +1.9) | 4.88 |
| 2014.04 | 143.9 | 144.8 | 84.7 | (81.0 projected, +0.7) | 7.88 |
| 2014.05 | 129.7 | 132.9 | 75.2 | (79.2 projected, -1.8) | 5.75 |
| 2014.06 | 122.0 | 125.8 | 71.0 | (76.6 projected, -2.6) | 6.72 |
| 2014.07 | 137.4 | 141.8 | 72.5 | (73.6 projected, -3.0) | 4.50 |
| 2014.08 | 124.7 | 127.9 | 74.7 | (70.1 projected, -3.5) | 7.71 |
| 2014.09 | 139.8 (1) | 95.7 (2A) / 119.7 (2B) / 83.8 (2C) | (65.9 projected, -4.2) | (9.4) | |
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 WDC-SILSO international sunspot number is typically 30-50% lower. 2B)
Boulder SN current month
average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices.
Values in red are based on the definitive
international
GFZ Potsdam
WDC
ap indices.
This report has been prepared by Jan Alvestad. It is based on the 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.
