The geomagnetic field was quiet to unsettled on December 22 under the influence of a high speed stream from CH1049. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 140.4 - increasing 46.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 80.98). The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.8). Three hour interval K indices: 23223233 (planetary), 12223220 (Boulder), 32223345 (Andenes).
The background x-ray flux is at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 255) and in 10 active regions using 1K resolution (SN: 164) SDO/HMI images.
Region 12907 [S20W51] gained area and could
produce M class events. There is less polarity intermixing than one day ago.
C1 flares: C1.5 @ 04:36, C1.1 @ 21:27, C1.9 @ 23:53 UT.
Region 12908
[S21W39] decayed losing spots and area. Despite of this the region remained
unstable.
Region 12909 [S20W24] was mostly quiet and stable.
Region 12911 [N21W11] was quiet and stable.
Region 12912 [S11E28] was quiet and stable.
Region 12915 [N16E24] decayed slowly and quietly.
Region 12916 [S17E68] rotated fully into view. There is a chance of M
class flaring.
New region 12917 [S27E30] emerged on December 21 and was numbered by
SWPC the next day. The region developed slowly and quietly.
New region 12918 [N20E52] emerged on December 21 with NOAA/SWPC
numbering the region the following day. The region developed fairly quickly
on December 22. C1 flares: C1.3 @ 20:46 UT.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7239 [S18W39] did not change significantly and could produce C
flares. SWPC
includes these spots in AR 12908.
S7252 [N19E34] decayed slowly and quietly.
New region S7256 [S19E21] was observed with tiny spots in an old
plage area.
C2+ flares:
| Magnitude | Peak time (UT) | Location | AR | Recorded by | Comment |
| C5.7 | 00:21 | S17E80 | 12916 | GOES16 | |
| C4.0 | 05:42 | S24W45 | 12907 | GOES16 | |
| M1.3/1N | 07:06 | S23W27 | 12908 | GOES16 | moderate type II radio sweep |
| C2.9 | 10:11 | S22W38 | 12907 | GOES16 | |
| C3.4 | 10:18 | 12907 | GOES16 | ||
| C2.0 | 11:09 | 12908 | GOES16 | ||
| C8.8/1N | 18:08 | S22W50 | 12907 | GOES16 | |
| C2.4 | 19:39 | 12907 | GOES16 | ||
| C2.0 | 22:18 | 12908 | GOES16 |
December 21-22: No obviously Earth directed CMEs
were observed in available LASCO imagery.
December 20: A faint halo CME was observed after the M1.8 LDE in AR
12908.
[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 trans equatorial coronal hole (CH1049) rotated across the central meridian on December 17-18.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to unsettled on December 23 due to effects from CH1049. A CME could reach Earth after noon on December 23 and cause unsettled to minor storm conditions that day and on December 24. Quiet to unsettled is expected for December 25-26.
| 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).
4K 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 officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. 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. SWPC data considered to be not sufficiently precise (location, area, classification) are red colored.
| Active region | SWPC date numbered STAR detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with magnetic polarity overlays |
Comment | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| SWPC/ USAF |
Magnetic (SDO) |
SWPC | STAR | Current | Previous | ||||||
| 2K | 1K | ||||||||||
| 12907 | 2021.12.12 2021.12.13 |
14 | 33 | 19 | S21W50 | 0230 | EAI | EAI |
 |
 |
beta-gamma |
| 12906 | 2021.12.13 2021.12.13 |
S29W85 | |||||||||
| 12908 | 2021.12.14 2021.12.15 |
16 | 5 | 2 | S20W39 | 0100 | DAI | CRO |
 |
 |
area: 0025 SWPC data includes AR S7239 location: S21W39 |
| 12909 | 2021.12.14 2021.12.15 |
3 | 8 | 5 | S21W26 | 0070 | HSX | CSO |
 |
 |
location: S21W24 |
| S7239 | 2021.12.15 | 35 | 16 | S18W39 | 0100 | DRI |
 |
 |
|||
| 12911 | 2021.12.16 2021.12.16 |
1 | 7 | 2 | N20W12 | 0010 | AXX | CRO |
 |
 |
area: 0020 location: N21W11 |
| 12913 | 2021.12.17 2021.12.20 |
S28E05 |
 |
||||||||
| 12914 | 2021.12.18 2021.12.21 |
S17E09 |
 |
||||||||
| 12912 | 2021.12.18 2021.12.19 |
1 | 6 | 2 | S12E27 | 0020 | HRX | CSO |
 |
 |
area: 0040 |
| S7246 | 2021.12.18 | N15W45 | |||||||||
| 12915 | 2021.12.18 2021.12.21 |
3 | 5 | 3 | N16E22 | 0030 | DRO | DRO |
 |
 |
area: 0040 |
| S7248 | 2021.12.18 | S10W26 | |||||||||
| S7250 | 2021.12.20 | S21W09 | |||||||||
| 12916 | 2021.12.21 2021.12.21 |
3 | 8 | 4 | S17E69 | 0240 | DSO | EHO |
 |
 |
area: 0490 |
| S7252 | 2021.12.21 | 2 | N19E34 | 0002 | AXX |
 |
 |
||||
| S7253 | 2021.12.21 | N24E51 |
 |
||||||||
| 12918 | 2021.12.21 2021.12.22 |
4 | 12 | 7 | N20E52 | 0020 | CRO | DAO |
 |
 |
area: 0120 |
| 12917 | 2021.12.21 2021.12.22 |
2 | 11 | 4 | S27E30 | 0010 | BXO | CRO |
 |
 |
area: 0025 |
| S7256 | 2021.12.22 | 3 | S19E21 | 0005 | BXO |
 |
|||||
| Total spot count: | 47 | 135 | 64 | ||||||||
| Sunspot number: | 137 | 255 | 164 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 76 | 180 | 109 | (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): | 151 | 140 | 131 | ||||||||
| Month | Average solar flux | International sunspot number (WDC-SILSO) |
Smoothed sunspot number (4) | Average ap (3) |
|
|---|---|---|---|---|---|
| Measured | 1 AU | ||||
| 2014.02 | 170.3 (cycle peak) |
166.3 | 146.1 (SC24 peak) | 110.5 | 10.70 |
| 2014.04 | 143.9 | 144.8 | 112.5 | 116.4 (solar max) | 7.88 |
| 2017.09 | 91.3 | 92.3 | 43.6 | 18.2 (-1.3) | 18.22 (cycle peak) |
| 2019.11 | 70.2 | 68.7 | 0.5 | 2.0 (-0.6) (Solar minimum using 365d smoothing: November 17, 2019) |
4.19 |
| 2019.12 | 70.8 | 68.6 | 1.6 | 1.8 (-0.2) (ISN 13 months smoothed solar minimum) |
3.22 |
| 2020.06 | 69.5 | 71.7 | 5.8 | 7.9 (+2.3) | 3.75 |
| 2020.07 | 69.5 | 71.8 | 6.3 | 9.0 (+1.1) | 4.28 |
| 2020.08 | 71.6 | 73.4 | 7.6 | 9.5 (+0.5) | 5.68 |
| 2020.09 | 70.7 | 71.4 | 0.7 | 10.5 (+1.0) | 8.59 |
| 2020.10 | 74.6 | 74.2 | 14.6 | 11.9 (+1.4) | 6.13 |
| 2020.11 | 89.9 | 88.0 | 34.5 | 13.6 (+1.7) | 4.77 |
| 2020.12 | 86.9 | 84.2 | 23.1 | 15.3 (+1.7) | 4.72 |
| 2021.01 | 76.0 | 73.6 | 10.4 | 17.3 (+2.0) | 4.39 |
| 2021.02 | 74.3 | 72.4 | 8.3 | 19.1 (+1.8) | 9.50 |
| 2021.03 | 76.0 | 75.2 | 17.3 | 21.8 (+2.7) | 10.17 |
| 2021.04 | 75.9 | 76.4 | 24.5 | 24.9 (+3.1) | 8.40 |
| 2021.05 | 75.3 | 77.1 | 21.2 | 25.9 (+1.0) | 6.50 |
| 2021.06 | 79.4 | 81.8 | 25.3 | (26.9 projected, +1.0) | 5.52 |
| 2021.07 | 81.0 | 83.6 | 34.4 | (29.9 projected, +3.0) | 5.51 |
| 2021.08 | 77.7 | 79.7 | 22.4 | (34.6 projected, +4.7) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.5 | (40.3 projected, +5.7) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 38.1 | (44.7 projected, +4.4) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 35.1 | (49.3 projected, +4.6) | 9.83 |
| 2021.12 | 96.4 (1) | 40.4 (2A) / 56.9 (2B) / 62.9 (2C) | (55.1 projected, +5.8) | (6.9) | |
| 2022.01 | (58.7 projected, +3.6) | ||||
| 2022.02 | (63.5 projected, +4.8) | ||||
| 2022.03 | (68.9 projected, +5.4) | ||||
| 2022.04 | (74.0 projected, +5.1) | ||||
| 2022.05 | (80.4 projected, +6.4) | ||||
1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz
and any corrections applied to that measurement.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days).
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.
4) Source: SIDC-SILSO.
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 Universal Time. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.
