The geomagnetic field was very quiet on March 13. Solar wind speed at SOHO ranged between 306 and 400 km/sec. The high latitude magnetometer at Andenes recorded very quiet levels. A sudden increase in the total field of the IMF and a quick increase in solar wind speed at 03:58 UT on March 14 signalled the arrival of the March 10 CME.
Solar flux density measured at 20h UT on 2.8 GHz was 143.3 - decreasing 36.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 137.06). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.4). Three hour interval K indices: 10000101 (planetary), 11101211 (Boulder), 00000101 (Andenes).
The background x-ray flux was at the class B6 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 236) and in 11 active regions using 1K resolution (SN: 160) SDO/HMI images.
Region 13245 [S23W56] decayed slowly and
quietly.
Region 13246 [N23W38] decayed further and could soon become spotless.
Region 13247 [S24W19] developed as new flux emerged in the trailing
spot section.
Region 13249 [S12W02] decayed slowly and quietly.
Region 13250 [S19W07] was mostly quiet and stable. C1 flares: C1.0 @
17:27 UT
Region 13251 [S14E18] was quiet and stable.
Region 13252 [N12E19] decayed slowly and quietly.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8346 [N29W22] reemerged with tiny spots.
S8348 [N22E07] was quiet and stable.
S8355 [N14W07] developed slowly and quietly.
S8360 [N23E33] reemerged with tiny spots.
New region S8362 [N08E44] emerged with tiny spots.
New region S8363 [S07E28] emerged with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.1 | 11:06 | N29W06 | filament eruption | GOES16 |
March 13: A partial halo CME was observed after a filament eruption
in the northeast quadrant near the central meridian just5 before noon.
Component from this CME could reach Earth on March 16. A very impressive
backsided full halo CME was observed in LASCO C3 imagery starting at 03:54
UT, the source was likely 5-6 days behind the northeast limb. An associated
above 10 MeV proton event began at 07:40 and peaked at 13.2 pfu at 14:30 UT.
March 12: No obviously Earth directed CMEs were observed.
March 11: A partial halo CME was observed after a large filament
eruption in the southwest quadrant. The eruption began slowly at
approximately 11:25 UT and peaked several hours later. The CME could reach
Earth after noon on March 14 and cause unsettled to minor storm conditions.
[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 (CH1134) was in an Earth facing position on March 11-12. A recurrent southern hemisphere coronal hole (CH1135) will likely rotate across the central meridian on March 16-17.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
Quiet to minor storm conditions are likely on March 14-17 due to CME and 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).
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 colored red.
| 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 | ||||||||||
| 13241 | 2023.02.28 2023.03.01 |
N28W88 |
 |
location: N29W84 |
|||||||
| 13242 | 2023.03.01 2023.03.02 |
1 | N13W86 | 0080 | HSX |
 |
location: N11W88 rotated out of view |
||||
| 13245 | 2023.03.02 2023.03.03 |
1 | 12 | 6 | S23W57 | 0250 | HHX | CSO |
 |
 |
area: 0270 location: S23W56 |
| 13246 | 2023.03.04 2023.03.05 |
2 | 1 | N24W40 | 0004 | AXX |
 |
 |
location: N23W38 | ||
| 13247 | 2023.03.05 2023.03.06 |
2 | 27 | 9 | S19W24 | 0060 | HAX | ESI |
 |
 |
location: S24W19 area: 0100 |
| S8343 | 2023.03.06 | S12W56 | |||||||||
| 13249 | 2023.03.07 2023.03.07 |
2 | 13 | 6 | S11W06 | 0020 | CRO | CAO |
 |
 |
location: S12W02 area: 0050 |
| S8346 | 2023.03.07 | 3 | 1 | N29W22 | 0005 | AXX |
 |
||||
| S8348 | 2023.03.08 | 3 | N22E07 | 0006 | AXX |
 |
 |
||||
| 13251 | 2023.03.08 2023.03.09 |
1 | 10 | 4 | S13E16 | 0050 | HSX | CSO |
 |
 |
area: 0090 location: S14E18 |
| S8350 | 2023.03.08 | N13W42 | |||||||||
| 13252 | 2023.03.09 2023.03.10 |
1 | 4 | 2 | N12E20 | 0020 | HRX | HAX |
 |
 |
location: N12E19 area: 0030 |
| 13250 | 2023.03.09 2023.03.09 |
9 | 20 | 14 | S18W08 | 0030 | DRI | DAI |
 |
 |
location: S19W07 area: 0070 |
| S8354 | 2023.03.10 | S15W46 | |||||||||
| S8355 | 2023.03.10 | 6 | 4 | N14W07 | 0012 | BXO |
 |
 |
|||
| S8356 | 2023.03.10 | S28E04 | |||||||||
| 13253 | 2023.03.11 2023.03.12 |
S30W14 |
 |
location: S29W12 | |||||||
| S8359 | 2023.03.11 | N15W25 | |||||||||
| S8360 | 2023.03.11 | 3 | 2 | N23E33 | 0005 | AXX |
 |
||||
| S8362 | 2023.03.13 | 2 | N08E44 | 0004 | BXO |
 |
|||||
| S8363 | 2023.03.13 | 1 | 1 | S07E28 | 0003 | AXX |
 |
||||
| Total spot count: | 17 | 106 | 50 | ||||||||
| Sunspot number: | 87 | 236 | 160 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 51 | 136 | 80 | (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): | 96 | 130 | 128 | ||||||||
| 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 (SC24 solar max) | 7.88 |
| 2017.09 | 91.3 | 92.3 | 43.6 | 18.2 (-1.3) | 18.22 (SC24 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 |
| 2021.08 | 77.7 | 79.7 | 22.0 | 35.4 (+4.0) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.2 (+4.8) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 37.4 | 45.2 (+5.0) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 34.8 | 50.8 (+5.6) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.5 | 55.9 (+5.1) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 55.3 | 60.1 (+4.2) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 60.9 | 64.7 (+4.6) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.6 | 68.7 (+4.0) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.0 | 73.0 (+4.3) | 11.79 |
| 2022.05 | 133.8 | 136.8 | 96.5 | 77.2 (+4.2) | 7.48 |
| 2022.06 | 116.1 | 119.8 | 70.3 | 80.9 (+3.7) | 8.20 |
| 2022.07 | 125.4 | 129.5 | 91.4 | 86.5 (+5.6) | 9.51 |
| 2022.08 | 114.2 | 117.1 | 74.6 | 92.3 (+5.8) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | (97.0 projected, +4.7) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.4 | (100.2 projected, +3.2) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 77.6 | (103.0 projected, +2.8) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 113.1 | (107.8 projected, +4.8) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (113.8 projected, +6.0) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (118.9 projected, +5.1) | 14.6 |
| 2023.03 | 170.7 (1) | 55.9 (2A) / 133.3 (2B) / 149.2 (2C) | (122.0 projected, +3.1) | (11.3) | |
| 2023.04 | (127.4 projected, +5.4) | ||||
| 2023.05 | (133.2 projected, +5.8) | ||||
| 2023.06 | (136.4 projected, +3.2) | ||||
| 2023.07 | (135.9 projected, -0.5) | ||||
| 2023.08 | (136.9 projected, +1.0) | ||||
| 2023.11 | (142.5 projected max SC25) | ||||
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.
