Solar Terrestrial Activity Report

Last major update issued on February 2, 2015 at 04:45 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, 2015)] [Cycle 24 progress (last update February 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 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 January 25, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to minor storm on February 1. Solar wind speed at SOHO ranged between 392 and 635 km/s. The disturbance that began late on January 31 intensified with minor storming observed late on February 1. Solar wind speed increased gradually peaking near 20h UTC.

Solar flux at 20h UTC on 2.8 GHz was 141.7 (decreasing 0.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.2. The Potsdam WDC planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 19.8). Three hour interval K indices: 42322345 (planetary), 42222344 (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 231) and 8 active regions using 1K resolution (SN: 160) SDO images on the visible solar disk.

Region 12268 [S09W62] decayed further and produced a few low level C flares.
Region 12271 [N18W79] rotated partly out of view.
Region 12272 [N12W21] decayed slowly and quietly.
Region 12277 [N08E23] extended further to cover 28 degrees longitudinally. The region has polarity intermixing and a minor M class flare is still possible.
Region 12278 [S08W13] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4186 [S14E18] was quiet and stable.
S4189 [S19W45] developed slowly and quietly.
New region S4191 [N36E40] emerged with a penumbra spot.
New region S4192 [S01E48] was observed with penumbra spots.

C2+ flares (GOES):

Coronal mass ejections (CMEs)

January 30 - February 1: No obviously Earth directed CMEs were observed in 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]

An extension of the southern polar coronal hole was associated with a co-rotating interaction region transiting the central meridian on January 29-30.

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 fair.

Forecast

The geomagnetic field is expected to be quiet to active on February 2 and quiet to unsettled on February 3-4.

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
12268	2015.01.21 2015.01.22	18	24	15	S11W57	0320	FKI	EAI			area: 0230 location: S09W62
12270	2015.01.22 2015.01.23				S18W71						plage
12271	2015.01.23 2015.01.25	3	2	2	N18W84	0180	EAO	HAX
12278	2015.01.25 2015.01.29		14	6	S08W18	0024		BXO
12272	2015.01.25 2015.01.26	2	6	2	N13W22	0020	HRX	CRO			area: 0012
12273	2015.01.25 2015.01.26	1			S03W82	0010	AXX				spotless
12275	2015.01.26	2			S17W94	0060	CAO				rotated out of view
12276	2015.01.27 2015.01.28				S07W31						plage
12277	2015.01.27 2015.01.28	46	73	43	N08E20	0440	FKC	FKC			beta-gamma area: 0550 location: N08E23
S4185	2015.01.28				S23W57						plage
S4186	2015.01.30		7	2	S14E18	0015		AXX
S4187	2015.01.30				S37W44						plage
S4189	2015.01.31		11	9	S19W45	0030		CRI
S4191	2015.02.01		1		N36E40	0001		AXX
S4192	2015.02.01		3	1	S01E48	0006		AXX
Total spot count:		72	141	80
Sunspot number:		132	231	160	(total spot count + 10 * number of spotted regions)
Weighted SN:		105	167	118	(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	81	88	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

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.