The geomagnetic field was quiet to minor storm on April 2 under the influence of CME effects (a solar wind shock was observed at 00:19 UT at DSCOVR, the arrival of the March 30 CME). The high latitude magnetometer at Andenes recorded quiet to major storm levels.
Solar flux density measured at 20h UT on 2.8 GHz was 143 - increasing 27.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 90.52). The Potsdam WDC planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 20.0). Three hour interval K indices: 45422343 (planetary), 45523343 (Boulder), 66523465 (Andenes).
The background x-ray flux is at the class B8 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 245) and in 9 active regions using 1K resolution (SN: 151) SDO/HMI images.
Region 12975 [N14W77] produced 2 M and several
C flares as it rotated to the northwest limb.
Region 12976 [N14W63] was the source of a long duration M3.9 proton
flare as the region decayed further.
Region 12978 [S17W01] was less active than on the previous and
appears to be slowly decaying. C1 flares: C1.5 @ 22:52 UT
Region 12981 [S25E05] decayed slowly and produced a couple of C
flares.
Region 12982 [S19E37] decayed slowly and quietly.
New region 12983 [N24E41] rotated into view on March 30 and was
numbered by SWPC 3 days later.
New region 12984 [N12W68] emerged on April 1 with SWPC numbering the
region the following day. Slow decay was observed after noon.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7469 [S17E10] decayed slowly and quietly.
S7471 [N12W16] decayed slowly and quietly.
New region S7475 [S20E81] rotated into view with a single mature
spot.
New region S7477 [N23W11] was observed with tiny spots.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C3.2 | 01:06 | 12975 | GOES16 | ||
| M2.9 | 02:56 | 12975 | GOES16 | ||
| C2.0 | 04:24 | 12981 | GOES16 | ||
| C3.9 | 05:05 | 12981 | GOES16 | ||
| C2.1 | 06:29 | 12975 | GOES16 | attributed to AR 12984 by SWPC | |
| C2.2 | 07:06 | 12975 | GOES16 | ||
| C2.5 | 07:36 | 12984 | GOES16 | ||
| C6.4 | 07:43 | S26E17 | 12981 | GOES16 | |
| C6.5 | 08:25 | N13W67 | 12975 | GOES16 | simultaneous flare in AR 12978 |
| C3.4 | 08:39 | 12975 | GOES16 | ||
| C2.6 | 10:46 | 12978 | GOES16 | ||
| M3.9/1N | 13:55 | N15W61 | 12976 | GOES16 | LDE, partial halo CME, proton event, moderate type II radio sweep. Flare covered a large area, including parts of AR 12984 and 12975. |
| M4.3/1N | 17:44 | N14W78 | 12975 | GOES16 | |
| C2.5 | 20:23 | 12975 | GOES16 |
April 1: No obviously Earth directed CMEs
were observed in available LASCO imagery.
April 2: A wide CME was observed after the M3.9 proton long duration
event in regions 12976/12975/12984 peaking at 13:55 UT. There is a chance
that parts of this CME will reach Earth on April 5.
[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 southern hemisphere coronal hole (CH1071) rotated across the central meridian on March 30-31.
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.
Quiet to active conditions is likely on April 3 due to CME effects becoming quiet to unsettled on April 4. April 5 could see the arrival of the April 2 CME.
| 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 | ||||||||||
| 12974 | 2022.03.21 2022.03.22 |
S19W83 |
location: S20W77 |
||||||||
| 12975 | 2022.03.22 2022.03.23 |
9 | 11 | 4 | N15W78 | 0260 | EKC | EAI |
 |
 |
beta-gamma location: N14W77
|
| 12976 | 2022.03.22 2022.03.24 |
4 | 7 | 5 | N18W58 | 0420 | EHO | EKO |
 |
 |
location: N14W63 |
| 12979 | 2022.03.25 2022.03.28 |
S22W62 |
 |
location: S17W51 | |||||||
| 12978 | 2022.03.27 2022.03.27 |
11 | 47 | 24 | S18E03 | 0420 | CHI | EKI |
 |
 |
location: S17W01 area: 0590 |
| S7457 | 2022.03.27 | N25W36 | |||||||||
| 12981 | 2022.03.27 2022.03.31 |
17 | 44 | 19 | S25E06 | 0080 | CRI | DRI |
 |
 |
beta-gamma |
| S7459 | 2022.03.27 | N40W44 | |||||||||
| S7461 | 2022.03.28 | N20W27 | |||||||||
| S7462 | 2022.03.28 | S14W24 |
 |
||||||||
| S7463 | 2022.03.28 | S42W16 | |||||||||
| S7464 | 2022.03.28 | S28W19 | |||||||||
| S7467 | 2022.03.29 | S19W39 | |||||||||
| 12982 | 2022.03.29 2022.04.01 |
1 | 10 | 3 | S19E34 | 0020 | AXX | CRO |
 |
 |
location: S19E37 |
| S7469 | 2022.03.30 | 3 | S18E18 | 0006 | BXO |
 |
 |
||||
| 12983 | 2022.03.30 2022.04.02 |
2 | 4 | 1 | N20E42 | 0040 | HSX | CAO |
 |
 |
location: N24E41 |
| S7471 | 2022.03.30 | 2 | 1 | N12W16 | 0004 | AXX |
 |
 |
|||
| S7472 | 2022.03.31 | N14E32 | |||||||||
| S7473 | 2022.03.31 | S26W09 | |||||||||
| 12984 | 2022.04.01 2022.04.02 |
4 | 4 | 3 | N12W69 | 0030 | DRO | DRO |
 |
 |
|
| S7475 | 2022.04.02 | 1 | 1 | S20E81 | 0070 | HAX |
 |
||||
| S7477 | 2022.04.02 | 2 | N23W11 | 0004 | BXO |
 |
|||||
| Total spot count: | 48 | 135 | 61 | ||||||||
| Sunspot number: | 118 | 245 | 151 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 89 | 179 | 105 | (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): | 130 | 135 | 121 | ||||||||
| 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 |
| 2020.08 | 71.6 | 73.4 | 7.5 | 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 | 8.2 | 19.0 (+1.7) | 9.50 |
| 2021.03 | 76.0 | 75.2 | 17.2 | 21.7 (+2.7) | 10.17 |
| 2021.04 | 75.9 | 76.4 | 24.5 | 24.8 (+3.1) | 8.40 |
| 2021.05 | 75.3 | 77.1 | 21.2 | 25.8 (+1.0) | 6.50 |
| 2021.06 | 79.4 | 81.8 | 25.0 | 27.7 (+1.9) | 5.52 |
| 2021.07 | 81.0 | 83.6 | 34.3 | 31.4 (+3.7) | 5.51 |
| 2021.08 | 77.7 | 79.7 | 22.0 | 35.3 (+3.9) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.3 | (39.9 projected, +4.6) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 38.1 | (43.6 projected, +3.7) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 35.0 | (48.2 projected, +4.6) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.6 | (54.0 projected, +5.8) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 54.0 | (57.7 projected, +3.7) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 59.7 | (62.4 projected, +4.7) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.3 | (67.9 projected, +5.5) | 10.1 |
| 2022.04 | 145 (1) | 7.6 (2A) / 113.5 (2B) / 95.5 (2C) | (73.0 projected, +5.1) | (17.4) | |
| 2022.05 | (79.4 projected, +6.4) | ||||
| 2022.06 | (85.3 projected, +5.9) | ||||
| 2022.07 | (92.6 projected, +7.3) | ||||
| 2022.08 | (99.2 projected, +6.6) | ||||
| 2022.09 | |||||
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.
