Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 12, 2016 at 03:35 UT.

Charts (* = updated daily Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (May 1, 2016)
Solar cycle Solar cycles 23-24 (May 1, 2016) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (May 1, 2016) Noon SDO sunspot count 1K / 4K (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (May 1, 2016) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (May 1, 2016) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (April 20, 2016)  

Recent activity

The geomagnetic field was quiet on May 11. Solar wind speed at SOHO ranged between 413 and 552 km/s.

Solar flux at 20h UTC on 2.8 GHz was 93.9 (decreasing 17.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 92.7. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.3). Three hour interval K indices: 21000112 (planetary), 32111212 (Boulder).

The background x-ray flux is at the class B2 level.

At the time of counting spots (see image time), spots were observed in 4 active regions using 2K resolution (SN: 127) and 4 active regions using 1K resolution (SN: 91) SDO images on the visible solar disk.

Region 12542 [N11W23] developed and became more complex. The chance of C flares has increased.
Region 12543 [S05W26] displayed no significant changes and was quiet.
Region 12544 [N21E36] merged with AR S5276 and developed slowly.
Region 12545 [S20W08] developed slowly and quietly.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

May 9-11: No obviously Earth directed CMEs were observed in available LASCO imagery. A filament eruption in the central northern hemisphere on May 9 may have been associated with a CME with a potentially Earth directed component, however, the lack of LASCO imagery at the time makes any forecast of CME effects uncertain.

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 recurrent northern hemisphere coronal hole (CH734) will likely rotate across the central meridian on May 12-13, no disturbance was associated with the CH on the previous rotation.

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 to fair.

Forecast

The geomagnetic field is expected to be quiet on May 12-14. If a CME was associated with the filament eruption on May 9, the CME could arrive late on May 12 and cause unsettled to active conditions.

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 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 overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12541 2016.05.01
2016.05.02
      N04W59           location: N03W46
12542 2016.05.03
2016.05.04
12 33 16 N11W23 0130 CAI DAC beta-gamma

area: 0230

12543 2016.05.07
2016.05.08
9 19 13 S05W27 0110 DAI DAI

area: 0140

12545 2016.05.08
2016.05.10
5 16 10 S21W09 0030 CRO DAI area: 0120
12544 2016.05.09 6 19 12 N21E33 0030 CSO DAI location: N21E36

area: 0060

S5276 2016.05.10       N20E39         merged with AR 12545
S5277 2016.05.10       N08E09          
Total spot count: 32 87 51  
Sunspot number: 72 127 91  (total spot count + 10 * number of spotted regions)
Weighted SN: 50 107 71  (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): 79 70 73 k * (sunspot number)
As of May 7, 2016: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.80 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO) (4)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2015.03 125.9 124.6 54.5 82.2 (-3.9) 16.14
2015.04 128.8 129.7 75.3 78.9 (-3.3) 10.73
2015.05 120.0 122.6 88.8 76.1 (-2.8) 8.29
2015.06 122.3 126.1 66.5 72.1 (-4.0) 13.15
2015.07 107.0 110.8 66.4 68.3 (-3.8) 8.83
2015.08 105.4 108.0 64.6 66.4 (-1.9) 14.58
2015.09 101.7 102.7 78.1 66.0 (-0.4) 15.78
2015.10 104.1 103.3 61.7 64.4 (-1.6) 14.02
2015.11 109.3 106.9 63.2 (61.2 projected, -3.2) 12.09
2015.12 113.1 109.5 57.7 (58.8 projected, -2.4) 14.29
2016.01 103.4 100.1 56.6 (57.1 projected, -1.7) 9.4
2016.02 103.6 101.0 57.2 (54.8 projected, -2.3) 9.9
2016.03 91.5 90.6 54.9 (51.9 projected, -2.9) 10.58
2016.04 93.3 94.0 38.0 (49.1 projected, -2.8) 9.03
2016.05 (89.3)   22.2 (2A) / 62.6 (2B) / 56.4 (2C) (47.2 projected, -1.9) (17.1)

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).
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) Updated to new data set from WDC-SILSO on July 1, 2015

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.