The geomagnetic field was quiet to active on March 16 due to CME effects early in the day. Solar wind speed at SOHO ranged between 445 and 582 km/sec. The high latitude magnetometer at Andenes recorded quiet to active levels.
Solar flux density measured at 20h UT on 2.8 GHz was 135.4 - decreasing 29.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 137.27). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.6). Three hour interval K indices: 43110010 (planetary), 43111211 (Boulder), 44221001 (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: 185) and in 10 active regions using 1K resolution (SN: 122) SDO/HMI images.
Region 13247 [S23W57] decayed slowly and
quietly.
Region 13249 [S10W42] decayed slowly and quietly.
Region 13250 [S18W47] decayed slowly and quietly.
Region 13251 [S13W20] was quiet and stable.
Region 13252 [N12W21] decayed slowly and quietly.
Region 13255 [S05E13] decayed slowly and quietly.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8348 [N22W33] was quiet and stable.
S8360 [N23W07] was quiet and stable.
S8365 [S18E21] decayed slowly and quietly.
S8366 [S18E43] was quiet and stable.
New region S8367 [S28E26] emerged with a tiny spot.
New region S8368 [S00W13] emerged with a tiny spot.
New region S8369 [S21E84] rotated into view
with a large, mature spot. The region has major flare potential and was the
source of C6.4 flares at 06:26 and 06:52 UT on March 17. C1 flares: C1.3 @ 05:43 UT.
AR 13245 produced a C1.4 flare at 12:55 UT while at the southwest limb. An active spotless region near the northeast limb was the source of a C1.2 flare at 16:02 UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
March 14-16: No obviously Earth directed CMEs were observed.
[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 recurrent southern hemisphere coronal hole (CH1135) will 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 very poor. Propagation on long distance northeast-southwest paths is poor.
Mostly quiet conditions are expected for March 17-19. Quiet to active is likely on March 20-21 due to effects from CH1135.
| 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 | ||||||||||
| 13246 | 2023.03.04 2023.03.05 |
N24W83 | location: N23W77 | ||||||||
| 13247 | 2023.03.05 2023.03.06 |
1 | 16 | 8 | S23W65 | 0010 | AXX | CRI |
 |
 |
location: S23W57 area: 0040 SWPC consider this to be 2 regions |
| 13249 | 2023.03.07 2023.03.07 |
1 | 1 | 1 | S11W44 | 0010 | AXX | HRX |
 |
 |
location: S10W42 area: 0012 |
| S8348 | 2023.03.08 | 3 | N22W33 | 0004 | AXX |
 |
 |
||||
| 13251 | 2023.03.08 2023.03.09 |
1 | 8 | 2 | S13W21 | 0040 | HSX | CSO |
 |
 |
area: 0060 location: S13W20 |
| 13252 | 2023.03.09 2023.03.10 |
1 | 5 | 2 | N13W21 | 0010 | AXX | CRO |
 |
 |
location: N12W21 |
| 13250 | 2023.03.09 2023.03.09 |
1 | 1 | 1 | S18W47 | 0010 | AXX | HRX |
 |
 |
|
| S8355 | 2023.03.10 | N13W48 | |||||||||
| S8356 | 2023.03.10 | S28W35 | |||||||||
| 13253 | 2023.03.11 2023.03.12 |
S29W58 | location: S29W51 | ||||||||
| S8360 | 2023.03.11 | 7 | 3 | N23W07 | 0015 | BXO |
 |
 |
|||
| S8362 | 2023.03.13 | N08E05 | |||||||||
| S8363 | 2023.03.13 | S09W09 | |||||||||
| 13254 | 2023.03.14 | 7 | S25W55 | 0030 | BXO | AR is inside the bi-polar area of AR 13247, however, SWPC considers it a new region | |||||
| 13255 | 2023.03.14 2023.03.14 |
2 | 5 | 1 | S05E13 | 0010 | BXO | BXO |
 |
 |
|
| S8365 | 2023.03.14 | 5 | 2 | S18E21 | 0010 | BXO |
 |
 |
|||
| S8366 | 2023.03.15 | 1 | 1 | S19E43 | 0002 | AXX |
 |
 |
|||
| S8367 | 2023.03.16 | 1 | S28E26 | 0001 | AXX |
 |
|||||
| S8368 | 2023.03.16 | 1 | S00W13 | 0001 | AXX |
 |
|||||
| S8369 | 2023.03.16 | 1 | 1 | S21E84 | 0340 | HHX |
 |
||||
| Total spot count: | 14 | 55 | 22 | ||||||||
| Sunspot number: | 84 | 185 | 122 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 19 | 82 | 49 | (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): | 92 | 102 | 98 | ||||||||
| 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) | 14.48 (current SC25 peak) |
| 2023.03 | 164.3 (1) | 64.8 (2A) / 125.4 (2B) / 140.7 (2C) | (122.0 projected, +3.1) | (12.5) | |
| 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.
