Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 25, 2015 at 06:35 UT.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2015)] [Cycle 24 progress (last update March 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2015)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated March 15, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on March 24. Solar wind speed at SOHO ranged between 463 and 573 km/s under the influence of a high speed stream from CH660.

Solar flux at 20h UTC on 2.8 GHz was 133.0 (increasing 22.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 128.9. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.4). Three hour interval K indices: 11123322 (planetary), 11223322 (Boulder).

The background x-ray flux is at the class B6 level.

At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 221) and 11 active regions using 1K resolution (SN: 163) SDO images on the visible solar disk.

Region 12303 [N19W27] was quiet and stable.
Region 12305 [S09E29] was quiet and stable. There is still a weak magnetic delta in the intermediate spot section. A minor M class flare is possible.
Region 12307 [S19W04] decayed slowly and quietly.
Region 12308 [N15W76] decayed slowly and quietly.
Region 12310 [N07E48] decayed in the leading spot section and was quiet. SWPC still considers this as two regions.
Region 12311 [N11W58] decayed slowly and quietly.
New region 12313 [N17E66] rotated into view on March 23 and lost the leader spot on March 24 when it was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4298 [S12E16] decayed slowly and quietly.
S4306 [S10W10] decayed slowly and quietly.
New region S4313 [S03E05] emerged early in the day with several spots.
New region S4315 [S10E47] emerged with a penumbra spot.
New region S4316 [N09E13] emerged with a penumbra spot.
New region S4317 [S07W37] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
         

Flare activity according to SDO/EVE/ESP XRS-B proxy

Coronal mass ejections (CMEs)

March 22-24: No obviously Earth directed CMEs were observed. A fast and large full halo CME from a backsided source was observed on March 24 from 09h UT.

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 southern hemisphere coronal hole (CH660) rotated over the central meridian on March 19-22.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on March 25 due to effects from CH660 and quiet on March 26-27.

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) 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 numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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.

Active region Date numbered
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12303 2015.03.16
2015.03.17
7 11 5 N19W30 0100 CAO CAO area: 0140
S4292 2015.03.18       S15W21            
12308 2015.03.19
2015.03.22
1 2 2 N16W75 0050 HAX CAO area: 0110
12307 2015.03.19
2015.03.22
3 7 5 S19W04 0010 BXO CRO  
S4296 2015.03.19       N21W12            
S4298 2015.03.19   6 4 S12E16 0014   BXO images/AR_S4298_20150324_2345.png  
12309 2015.03.20
2015.03.22
1     N14W36 0000 AXX     spotless
12305 2015.03.20
2015.03.21
15 40 23 S08E32 0340 EKC EKC beta-gamma-delta

area: 0630

S4301 2015.03.20       S03W10            
S4302 2015.03.20       N09W50            
S4305 2015.03.22       S02W01          
S4306 2015.03.22   2   S10W10 0004   AXX  
12310 2015.03.22
2015.03.23
4 11 5 N06E41 0020 CAO EAO area: 0080

location: N07E48

12311 2015.03.23 2 1 1 N11W60 0000 AXX AXX  
12312 2015.03.23 3     N08E54 0030 CAO       trailing part of AR 12310
S4308 2015.03.23       N21W02          
S4310 2015.03.23       S21E47          
S4311 2015.03.23       S25E65          
12313 2015.03.23
2015.03.24
1 1 1 N18E63 0030 HSX HAX location: N17E66

area: 0070

S4313 2015.03.24   7 5 S03E04 0020   BXO    
S4315 2015.03.24   1 1 S10E47 0003   AXX    
S4316 2015.03.24   1   N09E13 0003   AXX    
S4317 2015.03.24   1 1 S07W37 0005   AXX    
Total spot count: 37 91 53  
Sunspot number: 127 221 163  (total spot count + 10 * number of spotted regions)
Weighted SN: 72 124 86  (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): 76 77 90 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1)
(likely solar max)
7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.6 (-1.1) 4.50
2014.08 124.7 127.9 74.7 75.6 (-3.0) 7.71
2014.09 146.6 148.1 87.6 (71.6 projected, -4.0) 9.78
2014.10 153.4 152.9 60.6 (69.2 projected, -2.4) 8.96
2014.11 154.8 151.4 70.1 (67.4 projected, -1.8) 9.33
2014.12 158.7 153.8 78.0 (66.3 projected, -1.1) 11.24
2015.01 141.9 137.3 67.0 (65.1 projected, -1.2) 9.46
2015.02 129.1 126.0 44.8 (63.6 projected, -1.5) 9.92
2015.03 (122.7)   42.7 (2A) / 55.2 (2B) / 55.2 (2C) (61.6 projected, -2.0) (17.6)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official WDC-SILSO international sunspot number is typically 30-50% lower. 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.

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 the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.