Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 11, 2022 at 08:25 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (May 1, 2022)
Solar cycle Solar cycles 23-25 (May 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (May 1, 2022) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (June 1, 2020) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21-25 (May 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (May 1, 2022) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (April 10, 2022) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing

Recent activity

The geomagnetic field was very quiet on May 10. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 115.8 - increasing 17.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 95.90). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.3). Three hour interval K indices: 01001101 (planetary), 10013311 (Boulder), 21002214 (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 5 active regions using 2K resolution (SN: 146) and in 3 active regions using 1K resolution (SN: 67) SDO/HMI images.

Region 13006 [S31W06] developed slowly until the X1.5 flare at 13:55 UT, then decayed losing spots and area. While there is still a magnetic delta in the northern part of the region, it is significantly smaller than before the flare and is embedded within rudimentary penumbra. An M class flare is possible given the history of the region. C1 flares: C1.0 @ 11:55 UT
Region 13007 [S23E45] developed in the intermediate spot section gaining area and spots. An M class flare is possible. C1 flares: C1.6 @ 01:51, C1.4 @ 03:33, C1.9 @ 10:01, C1.7 @ 10:38, C1.8 @ 13:14, C1.6 @ 23:15 UT

Spotted regions not observed (or interpreted differently) by SWPC:
S7551 [N34W09] was quiet and stable.
S755
6 [N19W10] was quiet and stable.
New region S7558 [N17E49] emerged with tiny spots.

AR 13004 behind the southwest limb was the source of an C1.2 flare at 18:36 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.9 07:55 S20E57 13007 GOES16  
C2.8 12:58 S30W03 13006 GOES16  
C4.7/1F 13:36 S22E52 13007 GOES16 LDE
X1.5/1B 13:55 S30W04 13006 GOES16 strong type II radio sweep, fast EIT wave
M1.0 14:33 S33E00 13006 GOES16 LDE, weak type IV radio sweep, CME
C3.2 16:36   13007 GOES16  
C2.1 22:07 behind SE limb   GOES16 LDE, CME, incorrectly attributed to AR 13007 by SWPC

Coronal mass ejections (CMEs)

May 8-10: No obviously Earth directed CMEs were observed in available LASCO imagery.

Coronal holes

[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 small northern hemisphere coronal hole (CH1077) rotated across the central meridian on May 7.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair to good. Propagation on long distance northeast-southwest paths is poor.

Forecast

Mostly quiet conditions are likely on May 10-12 with a chance of unsettled intervals due to weak effects from CH1077 on May 10-11.

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.

Active solar regions


(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
13006 2022.05.02
2022.05.04
22 49 16 S30W07 0180 EAI DRI beta-gamma-delta

location: S31W06

area: 0100

S7540 2022.05.02       S13W22            
S7546 2022.05.05       S25W47            
S7548 2022.05.05       S18W32            
S7551 2022.05.06   2   N34W09 0003   BXO  
13007 2022.05.07
2022.05.08
20 41 20 S24E45 0240 ESI FAI

beta-gamma

S7554 2022.05.07       S29W37            
S7555 2022.05.08       N02E06           likely SC24 group
S7556 2022.05.09   2   N19W10 0002   AXX  
S7557 2022.05.09       S18E36          
S7558 2022.05.10   2 1 N17E49 0010   CRO    
Total spot count: 42 96 37  
Sunspot number: 62 146 67  (total spot count + 10 * number of spotted regions)
Weighted SN: 52 107 48  (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): 68 80 54  

Monthly solar cycle data

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
 

2020.10

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 27.6 (+1.8) 5.52
2021.07 81.0 83.6 34.3 31.3 (+3.7) 5.51
2021.08 77.7 79.7 22.0 35.3 (+4.0) 6.19
2021.09 87.0 88.2 51.3 40.0 (+4.7) 6.33
2021.10 88.9 88.3 37.4 45.0 (+5.0) 7.38
2021.11 86.2 84.4 34.8 (50.0 projected, +5.0) 9.83
2021.12 103.0 99.8 67.5 (55.8 projected, +5.8) 6.40
2022.01 103.8 100.5 54.0 (60.3 projected, +4.5) 8.92
2022.02 109.1 106.5 59.7 (65.2 projected, +4.9) 10.46
2022.03 117.0 115.8 78.5 (70.7 projected, +5.5) 10.20
2022.04 130.8 131.7 84.1 (75.9 projected, +5.2) 12.0
2022.05 117.5 (1)   21.3 (2A) / 65.9 (2B) / 89.0 (2C) (82.3 projected, +6.4) (4.6)
2022.06       (88.2 projected, +5.9)  
2022.07       (95.4 projected, +7.2)  
2022.08       (102.1 projected, +6.7)  
2022.09       (107.1 projected, +5.0)  
2022.10       (110.3 projected, +3.2)  

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.

Solar cycles 24-25

Smoothed SF and sunspot numbers

 

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.