Solar Terrestrial Activity Report

Last major update issued on January 9, 2013 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 January 1, 2013)] [Cycle 24 progress (last update January 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 2, 2013)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated January 8, 2013]

Recent activity

The geomagnetic field was quiet on January 8. Solar wind speed at SOHO ranged between 300 and 334 km/s, weakly under the influence of a low speed stream from CH549.

Solar flux measured at 20h UTC on 2.8 GHz was 155.6 (increasing 43.7 over the last solar rotation). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.6). Three hour interval K indices: 01010112 (planetary), 01001112 (Boulder).

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

At midnight UTC the visible solar disk had 16 spotted active regions (in 2K resolution SDO images).

Region 11642 [S24W28] was quiet and stable.
Region 11643 [S13W35] was quiet and stable.
Region 11644 [N15W17] decayed slowly and quietly.
Region 11645 [S14W57] decayed slowly and quietly.
Region 11646 [N13W08] decayed very quickly as the main spot disintegrated.
Region 11648 [N05W02] decayed slowly and quietly.
Region 11649 [S15E19] was quiet and stable.
Region 11650 [S28E27] decayed slowly and was mostly quiet.
Region 11652 [N20E38] developed early in the day, then began to decay. The region currently has no mature penumbra on any trailing spot.
Region 11653 [N08E36] decayed slowly and was mostly quiet.
New region 11654 [N08E76] rotated fully into view revealing one of the larger regions of solar cycle 24. The region appears to have a simple magnetic layout, still M flares are possible.

Spotted regions not numbered by SWPC:
S2160 [S18W16] was quiet and stable.
S2163 [S17W03] was quiet and stable.
New region S2164 [S17E64] emerged with small spots.
New region S2165 [S22E17] emerged with several spots.
New region S2166 [N27W22] emerged with a tiny spot.

Coronal mass ejections (CMEs)

January 6-8: No obviously Earth directed CMEs were observed in LASCO and STEREO 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

A small recurrent trans equatorial coronal hole (CH549) was in an Earth facing position on January 3-4.

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and 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 January 9-11.

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 (blue-green) 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
11638	2012.12.26 2012.12.27	1			N13W87	0060	HSX				rotated out of view
11641	2012.12.29 2012.12.31				N02W59						plage
11642	2012.12.30 2012.12.31	1	4	1	S25W29	0080	HSX	CSO			area: 0160
11643	2012.12.31 2013.01.02		4		S14W39	0000		AXX			location: S13W35
11644	2013.01.01 2013.01.02	1	4	1	N15W19	0040	HAX	HAX
11648	2013.01.02 2013.01.04		3	1	N05W03	0000		BXO
11646	2013.01.02 2013.01.03	3	5	3	N13W09	0030	HRX	AXX
11651	2013.01.02 2013.01.04				N20W05						plage
11645	2013.01.02 2013.01.03	5	3	2	S14W72	0030	CRO	CRO
11649	2013.01.03 2013.01.04	1	3	1	S15E18	0080	HSX	HSX			area: 0140
S2156	2013.01.03				N17W07						plage
11650	2013.01.04	7	19	12	S30E30	0120	EAO	EAO			location: S28E27 area: 0200
11652	2013.01.05	19	47	32	N19E38	0210	FAC	EAI			beta-gamma
11653	2013.01.05	4	3	3	N09E35	0030	CRO	CRO
S2157	2013.01.05				S02W10						plage
S2158	2013.01.05				N15W51						plage
S2159	2013.01.05				N25W33						plage
S2160	2013.01.06		1	1	S18W16	0000		AXX
11654	2013.01.07	2	12	6	N08E71	0260	HHX	EKO			location: N08E76 area: 0850
S2162	2013.01.07				N20E12						plage
S2163	2013.01.07		1		S17W03	0000		AXX
S2164	2013.01.08		2	2	S17E64	0000		BXO
S2165	2013.01.08		5	2	S22E17	0020		CRO
S2166	2013.01.08		1		N27W22	0000		AXX
Total spot count:		44	117	67
Sunspot number:		144	277	197	(total spot count + 10 * number of spotted regions)
Weighted SN:		93	161	111	(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):		86	97	108	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 SIDC 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 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.