Solar Terrestrial Activity Report

Last major update issued on February 1, 2014 at 05:20 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 January 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 1, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was very quiet on January 31. Solar wind speed at SOHO ranged between 277 and 368 km/s.

Solar flux at 20h UTC on 2.8 GHz was 165.7 (decreasing 37.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 147.0. The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 0.9). Three hour interval K indices: 00010000 (planetary), 10011211 (Boulder).

The background x-ray flux is at the class C1 level.

At the time of counting spots (see image time) spots were observed in 8 active regions in 2K resolution (SN: 245) and 4 active regions in 1K resolution (SN: 130) SDO images on the visible solar disk.

Region 11963 [S10W69] was quiet and stable.
Region 11967 [S12E31] was surprisingly quiet taking into consideration its complexity. Some development was observed in the northern central section. The region has 3 magnetic delta structures and is capable of producing M and X class flares. C5+ flare: C6.3 at 00:18 UTC on Feb.1 (the flare began at 23:59 UTC).
Region 11968 [N10E29] gained spots and has polarity intermixing. C5+ flare: M1.1 at 15:42 UTC. LASCO imagery indicates that this event was associated with a halo CME.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3071 [S10W20] developed slowly and quietly.
S3073 [N19E32] gained leading penumbra spots.
S3075 [S12E56] decayed slowly and quietly.
S3077 [N13E07] was first observed with a penumbra spot at noon at January 30, lost the spot by the end of the day, then reemerged on Jan.31.
New region S3079 [S13E45] emerged with penumbra spots.

Coronal mass ejections (CMEs)

January 29: A halo CME was observed after a filament eruption in the southwest quadrant. While the core of the CME will not reach Earth, there's a chance a weak solar wind shock will be observed on February 1.
January 30: A halo CME was observed after an M1 event in AR 11967 at 08:11 UTC. The CME was faint over the west limbs and the north pole. A much larger CME was observed after the M6 flare in AR 11967 at 16:11 UTC. This CME could reach Earth on February 2.
January 31: Although imagery is incomplete from the hours after the M1 event in AR 11968, LASCO C3 images indicate that there was a halo CME associated. The CME could reach Earth on February 3.

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 trans equatorial coronal hole (CH602) will likely rotate into an Earth facing position on February 5-6.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on February 1 with a chance of unsettled intervals due to weak CME effects. On February 2 quiet to active conditions are possible due to effects from the largest CME observed on January 30. On February 3 we can expect quiet to unsettled conditions.

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
11963	2014.01.19 2014.01.21		1		S18W82	0002		AXX			SWPC location on Jan.27: S06W25 location: S10W69
11964	2014.01.20 2014.01.21				S09W77						SWPC location on Jan.27: S14W28 location: S19W74 plage
11965	2014.01.20 2014.01.22				S15W70						SWPC location on Jan.28: S14W24 location: S14W53 spotless
S3055	2014.01.21				N15W59						plage
S3057	2014.01.22				N05W42						plage
S3060	2014.01.24				S01W59						plage
S3062	2014.01.24				S28W53						plage
S3064	2014.01.26				N23W37						plage
11967	2014.01.26 2014.01.27	49	94	57	S14E29	1000	FKC	FKC			beta-gamma-delta area: 2010 location: S12E31
11968	2014.01.27	18	54	27	N10E29	0210	EAI	ESC			beta-gamma area: 0300
S3070	2014.01.28				N13W11						plage
S3071	2014.01.28		6	4	S10W20	0015		CRO
S3072	2014.01.28				S15W69						plage SWPC has moved AR 11965 to this location
S3073	2014.01.28		4		N19E32	0007		BXO
S3074	2014.01.29				S17W33						plage
S3075	2014.01.29		2	2	S12E56	0011		AXX
S3076	2014.01.29				N13W24						plage
S3077	2014.01.30		1		N13E07	0002		AXX
S3078	2014.01.30				S23E04						plage
S3079	2014.01.31		3		S13E45	0006		AXX
Total spot count:		67	165	90
Sunspot number:		87	245	130	(total spot count + 10 * number of spotted regions)
Weighted SN:		82	183	108	(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):		52	86	72	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

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 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.