Solar Terrestrial Activity Report

Last major update issued on March 29, 2014 at 08:40 UTC.

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

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated March 16, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on March 28. Solar wind speed at SOHO ranged between 400 and 511 km/s.

Solar flux at 20h UTC on 2.8 GHz was 146.4 (decreasing 18.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.0 (new high for cycle 24). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.9). Three hour interval K indices: 11112123 (planetary), 11113333 (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 17 active regions in 2K resolution (SN: 344) and 16 active regions in 1K resolution (SN: 250) SDO images on the visible solar disk.

Region 12010 [S13W77] decayed slowly and quietly.
Region 12014 [S13W48] was quiet and stable.
Region 12017 [N10W22] developed in the leading spot section with a magnetic delta structure forming in the northern part of the largest penumbra. The delta disintegrated after the 2 M flares. C5+ flares: impulsive M2.0 at 19:18, M2.6 at 23:51 UTC. Both flares were accompanied by type II radio sweeps and a CME off the northwest limb.
Region 12018 [N04W15] decayed slowly and quietly.
Region 12020 [S11E07] decayed slowly and quietly.
New region 12021 [S12E49] emerged with several spots.
New region 12022 [N17E65] rotated into view on March 27 and was numbered by SWPC the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3248 [S03W35] decayed slowly and quietly.
S3271 [S19W00] developed early in the day, then decayed slowly.
S3272 [N12E05] was quiet and stable.
New region S3274 [S30W68] emerged early in the day with several spots with umbra, then decayed and had only penumbra spots left by the end of the day.
New region S3275 [N18E34] emerged with a few spots.
New region S3276 [S11E41] emerged with penumbra spots in an old plage region.
New region S3277 [S25E28] emerged with penumbra spots.
New region S3278 [S17E20] emerged with penumbra spots.
New region S3279 [S14W65] emerged with several spots.
New region S3280 [N09E26] emerged with a penumbra spot.

A full halo CME was observed after 18h UTC in LASCO imagery, its source was a backsided southern hemisphere active region.

Coronal mass ejections (CMEs)

March 26-28: 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 trans equatorial coronal hole (CH609) rotated into an Earth facing position on March 28-29.

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 on March 29-30. On March 31 and April 1 there's a chance of unsettled intervals due to coronal hole effects.

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
12010	2014.03.16 2014.03.17	10	8	5	S14W80	0080	DAO	DRI			location: S13W77
12012	2014.03.17 2014.03.18				S09W79						plage location: S16W50
12013	2014.03.17 2014.03.18				N15W67						plage
12016	2014.03.17 2014.03.22	3			S28W77		CRO				plage SWPC is probably counting the spots of AR S3274, 10 degrees further 10 east
12014	2014.03.18 2014.03.19	22	39	19	S15W46	0290	EHI	DSI			beta-gamma location: S13W48
S3248	2014.03.20		1		S03W35	0003		AXX
12017	2014.03.21 2014.03.22	14	43	18	N10W20	0150	DAO	EAI			beta-gamma area: 0250
S3255	2014.03.22				S12W25						plage
S3256	2014.03.22				S08W26						plage
S3259	2014.03.23				S20W26						plage
12018	2014.03.24	8	13	8	N03W16	0030	CRO	DRO
12020	2014.03.24 2014.03.27		6	4	S14E14	0010		BXO	images/AR_12020_20140328_2345.png		area: 0020
S3262	2014.03.24				S11W09
S3263	2014.03.25				S39W46						plage
S3264	2014.03.26				N08E26						plage
S3266	2014.03.26				S22W40						plage
S3267	2014.03.26				S22E32						plage
12022	2014.03.27 2014.03.28	1	1	1	N16E64	0060	HSX	HAX			area: 0050
S3271	2014.03.27		13	7	S19W00	0025		BXO	images/AR_S3271_20140328_2345.png
S3272	2014.03.27		4	2	N12E05	0010		BXO	images/AR_S3272_20140328_2345.png	images/AR_S3272_20140327_2345.png
12021	2014.03.28	7	18	11	S15E50	0040	DAO	DRI			area: 0090
S3274	2014.03.28		3	2	S30W68	0012		BXO
S3275	2014.03.28		4	1	N18E34	0012		HRX
S3276	2014.03.28		5	2	S11E41	0013		BXO
S3277	2014.03.28		6	2	S25E28	0022		BXO	images/AR_S3277_20140328_2345.png
S3278	2014.03.28		2	2	S17E20	0010		BXO
S3279	2014.03.28		7	5	S14W65	0030		DRO
S3280	2014.03.28		1	1	N09E26	0005		AXX
Total spot count:		65	174	90
Sunspot number:		135	344	250	(total spot count + 10 * number of spotted regions)
Weighted SN:		101	204	120	(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):		81	120	138	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.