Last major update issued on March 4, 2012 at 04:10 UTC. Minor update posted at 17:55 UTC.
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[POES auroral activity level since October
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Annotated geomagnetic activity charts - Carrington rotation 2118 [December 2011 - January 2012] - 2119 [January-February 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet to unsettled on March 3. Solar wind speed at SOHO ranged between 349 and 386 km/s. The disturbance intensified early on March 4 with minor storm conditions observed and the A index for the 00-03h UTC interval reached 39.
Solar flux measured at 17h UTC on 2.8 GHz was 111.5 (increasing 8.5 over the last solar rotation, the observation at 20h UTC was flare enhanced). The planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.0). Three hour interval K indices: 23321212 (planetary), 24331212 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight UTC the visible solar disk had 6 spotted active regions (in 2K resolution SDO images).
Region 11423 [N16W47] was quiet and stable.
Region 11427 [N15W30] decayed slowly. Flare: C1.3 at 03:08 UTC
New region 11428 [S16E51] emerged in the southeast quadrant on March 2 and was numbered by SWPC the next day. The region could produce C flares.
New region 11429 [N17E69] rotated into view at the northeast limb on March 2 and was assigned a number by SWPC the following day. The region is complex and compact with most spots inside a single, large penumbra. Major flares, even X class flares, are possible. Flares: C1.4 at 01:02, C1.2 at 05:20, long duration C2.8 peaking at 06:09, C1.1 at 18:03, long duration C1.9 peaking at 19:48 UTC.
Spotted regions not reported by NOAA/SWPC:
[S1504] emerged in the northeast quadrant on March 1. Location at midnight: N10W09
[S1509] emerged in the southeast quadrant on March 3. Location at midnight: S10E13
Minor update added at 17:55 UTC on March 4: Region 11429 produced a long duration M2.0/1N event peaking at 10:52 UTC. This event was associated with a wide CME, possibly a full halo CME, and a minor increase in proton background levels. Geomagnetic effects are possible on March 7.
Region 11429 continues to develop, has a strong magnetic delta structure and could produce major flares anytime. New region S1510 is emerging quickly to the west northwest of region 11429 and was located at N20E43 at 16:39 UTC. New region S1511 has emerged in the southwest quadrant today and was located at S27W18 at 16:39 UTC, while region S1498 has regained spots. See the latest high resolution CHARMAP.
March 1-3: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A coronal hole (CH505) in the southern hemisphere was in an Earth facing position on Feb.29-March 1. A recurrent, elongated coronal hole (CH506) in the southern hemisphere will rotate into an Earth facing position on March 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.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is good.
The geomagnetic field is expected to be quiet to minor storm on March 4 due to effects from CH505. Quiet conditions are likely on March 5. On March 6-8 a high speed stream from CH506 could cause quiet to unsettled conditions with occasional active intervals.
|Coronal holes (1)||Coronal mass ejections (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
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.
Click on image for higher resolution image) Compare to the previous day's 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
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|Total spot count:||12||28||13|
|Sunspot number:||52||88||53||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||33||49||34||(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):||31||31||29||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2010.12||84.2||14.4||28.8 (+2.3)||3.41 / 4.35|
|2011.01||83.6||19.1||31.0 (+2.2)||4.32 / 5.51|
|2011.02||94.6||29.4||33.4 (+2.4)||5.41 / 6.44|
|2011.03||115.0||56.2||36.9 (+3.5)||7.79 / 8.18|
|2011.04||112.6||54.4||41.8 (+4.9)||9.71 / 8.83|
|2011.05||95.8||41.6||47.6 (+5.8)||9.18 / 8.94|
|2011.06||95.8||37.0||53.2 (+5.6)||8.96 / 8.06|
|2011.07||94.2||43.9||57.2 (+4.0)||9.14 / 8.16|
|2011.08||101.7||50.6||59.0 (+1.8)||8.16 / 7.26|
|2011.09||133.8||78.0||(59.2 projected, +0.2)||12.80 / 12.27|
|2011.10||137.3||88.0||(59.4 projected, +0.2)||7.52 / 8.28|
|2011.11||153.5||96.7||(60.8 projected, +1.4)||4.58 / 5.55|
|2011.12||141.3||73.0||(63.6 projected, +2.8)||3.32|
|2012.01||132.5||58.3||(67.1 projected, +3.5)||6.59|
|2012.02||106.5||33.1||(71.0 projected, +3.9)||8.09|
|2012.03||107.7 (1)||3.2 (2A) / 33.3 (2B)||(73.2 projected, +2.2)||(11.50)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
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) Month average to date.
3) Running average based on the preliminary daily SWPC ap indices. Values in red are based on the official NGDC 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.