Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 27, 2014 at 05:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2014)] [Cycle 24 progress (last update February 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 23, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on February 26. Solar wind speed at SOHO ranged between 334 and 364 km/s.

Solar flux at 20h UTC on 2.8 GHz was 178.2 (increasing 17.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 152.5. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.8). Three hour interval K indices: 20000001 (planetary), 20002211 (Boulder).

The background x-ray flux is at the class B9 level.

At the time of counting spots (see image time) spots were observed in 21 active regions in 2K resolution (SN: 448) and 19 active regions in 1K resolution (SN: 310) SDO images on the visible solar disk.

Region 11981 [S08W60] decayed losing spots and penumbral area.
Region 11982 [S11W48] decayed slowly and lost the magnetic delta structure after the M class flare.
C5+ flare: M1.1/1N at 15:01 UTC.
Region 11983 [S14W63] developed slowly and quietly.
Region 11984 [S17W62] matured quickly and was quiet.
Region 11986 [N13W13] decayed slowly and quietly.
Region 11987 [S02E09] gained a few spots and was quiet.
Region 11989 [N08E26] decayed slowly and quietly.
Region 11990 [S12E52] was mostly quiet. With a strong magnetic delta structure inside the single large spot another major flare is possible.
New region 11991 [S25E67] rotated into view on February 25 and was numbered the next day by SWPC.
New region 11992 [S20E21] emerged on February 25 and received its NOAA number the following day.
New region 11993 [N17E58] emerged on February 25 and developed further on February 26 when it was numbered by SPWC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3141 [S06W49] decayed significantly and was quiet.
S3150 [S16W23] reemerged with penumbra spots.
S3155 [S06E12] was quiet and stable.
S3156 [N05E34] was quiet and stable.
S3163 [S11E33] was quiet and stable.
S3164 [N18E47] has tiny penumbra spots in an old plage area.
New region S3167 [N09W61] emerged early in the day, then decayed slowly during the latter hald of the day.
New region S3168 [S09W23] emerged quickly and could generate C flares.
New region S3169 [N11E45] emerged with penumbra spots.
New region S3170 [S23W31] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

February 24, 26: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
February 25: An asymmetric full halo CME was observed after the X4 flare in AR 11990. The CME will likely reach Earth on February 27.

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 negative polarity trans equatorial coronal hole (CH605) was in an Earth facing position on February 24-25.

Coronal hole map

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 minor storm on February 27-28 due to CME and coronal hole effects. Quiet to unsettled is likely on March 1.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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 STAR SDO SWPC STAR Current Previous
2K 1K
11983 2014.02.16
2014.02.18
  5 2 S13W73 0020   BXO

location: S14W63

11982 2014.02.16
2014.02.17
33 29 15 S09W50 0320 ESC ESC

beta-gamma

area: 0300

location: S11W48

11981 2014.02.16
2014.02.17
13 17 7 S08W47 0100 EAI ERI  
11984 2014.02.17
2014.02.18
8 10 3 S18W62 0060 CAO DAO

area: 0110

11986 2014.02.19
2014.02.20
13 23 10 N13W18 0010 BXO DRI

area: 0100

location: N13W13

S3141 2014.02.19   32 16 S06W49 0100   CAI  
11987 2014.02.21 14 26 18 S01E09 0190 DAI ESI

area: 0280

11988 2014.02.21
2014.02.22
      S10W21           plage

location: S10W18

S3150 2014.02.22   3 1 S16W23 0012   AXX   plage
11989 2014.02.22
2014.02.23
2 13 6 N09E26 0030 DAO CRO area: 0060

location: N08E26

S3154 2014.02.23       S27W19         plage
S3155 2014.02.23   7 5 S06E12 0025   CRO  
S3156 2014.02.23   5 1 N05E34 0020   HRX  
S3159 2014.02.24       S22W16           plage
11990 2014.02.24 3 9 4 S12E50 0210 DKC DKC delta

area: 0420

11991 2014.02.25
2014.02.26
4 13 8 S25E65 0120 DSO DAO area: 0280

location: S25E67

11992 2014.02.25
2014.02.26
3 12 8 S19E20 0010 CRO DRO area: 0080
S3163 2014.02.25   9 2 S11E33 0015   BXO  
S3164 2014.02.25   2   N18E47 0002   BXO  
11993 2014.02.25
2014.02.26
4 7 5 N16E57 0010 BXO CRO area: 0035
S3166 2014.02.25       N06W02         plage
S3167 2014.02.26   1   N09W61 0001   AXX    
S3168 2014.02.26   11 9 S09W23 0050   DRI    
S3169 2014.02.26   3 1 N11E45 0009   BXO    
S3170 2014.02.26   1 1 S23W31 0004   AXX    
Total spot count: 97 238 120  
Sunspot number: 197 448 310  (total spot count + 10 * number of spotted regions)
Weighted SN: 140 297 179  (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): 118 157 171 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2011.11 153.5   96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5   32.9 66.9 (+1.4) 8.81
2012.11 121.3 118.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 105.0 40.8 59.6 (-0.1) 3.44
2013.01 127.1 123.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 (69.0 projected, +3.5) 8.27
2013.09 102.6 103.7 36.9 (73.0 projected, +4.0) 5.23
2013.10  132.1 131.2 85.6 (74.0 projected, +1.0) 7.71
2013.11  148.3 145.1 77.6 (72.9 projected, -1.1) 5.68
2013.12 147.7 143.1 90.3 (71.8 projected, -1.1) 4.68
2014.01 157.4
(cycle peak)
152.4 82.0 (71.0 projected, -0.8) 5.44
2014.02 170.1 (1)   156.5 (2A) / 168.6 (2B) / 114.9 (2C) (71.2 projected, +0.2) (10.5)

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.