Last major update issued on April 1, 2014 at 05:05 UTC.
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SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on March 31. Solar wind speed at SOHO ranged between 366 and 440 km/s. A low speed stream from CH609 caused a minor increase in geomagnetic activity after noon.
Solar flux at 20h UTC on 2.8 GHz was 152.4 (decreasing 5.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.4 (new high for cycle 24). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 11112220 (planetary), 11114421 (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 15 active regions in 2K resolution (SN: 259) and 10 active regions in 1K resolution (SN: 148) SDO images on the visible solar disk.
Region 12017 [N10W64] decayed further and was quiet.
Region 12021 [S12E10] developed slowly and was mostly quiet. C and minor
M class flares are possible.
Region 12022 [N17E25] was quiet and stable.
Region 12024 [N17W06] was quiet and stable.
Region 12025 [S23W32] decayed slowly and quietly.
Region 12026 [S11E67] developed slowly and has polarity intermixing. C and M class
flaring is possible.
New region 12027 [N12E71] rotated into view on March 30 and was numbered
the next day by SWPC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3276 [S12E03] was quiet and stable.
S3277 [S27E01] was quiet and stable.
S3281 [S07W51] was quiet and stable.
S3285 [S10W23] decayed slowly and quietly.
New region S3287 [S30W79] emerged with apenumbra spot.
New region S3288 [N05E58] has a single penumbra spot.
New region S3289 [S08E77] rotated into view.
New region S3290 [S20E42] emerged with a penumbra spot.
AR 12014 produced an M1.4 flare at 08:07 UTC while at the southwest limb.
March 30-31: No obviously Earth directed CMEs were observed in LASCO and
STEREO imagery.
March 29: An asymmetric full halo CME was observed after the X1 flare in
AR 12017. The leading (shock) edge of the CME could reach Earth on April 1. The CME core was not Earth directed.
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.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on April 1 with a chance of active intervals if the shock from the CME observed on March 29 arrives. Quiet conditions are likely on April 2-4.
| Coronal holes (1) | Coronal mass ejection (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
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.
(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 | ||||||||||
| 12014 | 2014.03.18 2014.03.19 |
3 | S13W91 | 0150 | CAO |
 |
rotated out of view | ||||
| 12017 | 2014.03.21 2014.03.22 |
7 | 8 | 3 | N10W64 | 0060 | CAI | CRO |
 |
 |
area: 0020 |
| 12018 | 2014.03.24 | N04W59 |
 |
plage location: N05W56 |
|||||||
| 12020 | 2014.03.24 2014.03.27 |
2 | S13W25 | 0010 | BXO |
 |
location: S15W26 SWPC apparently includes the spot of AR S3285 |
||||
| S3262 | 2014.03.24 | S11W48 | plage | ||||||||
| S3264 | 2014.03.26 | N08W13 | plage | ||||||||
| S3267 | 2014.03.26 | S22W07 | plage | ||||||||
| 12022 | 2014.03.27 2014.03.28 |
1 | 1 | 1 | N17E24 | 0030 | HSX | HSX |
 |
 |
area: 0050 |
| 12025 | 2014.03.27 2014.03.30 |
4 | 8 | 4 | S24W33 | 0020 | CRO | CRO | images/AR_S3271_20140331_2345.png | images/AR_S3271_20140330_2345.png | location: S23W32 |
| S3272 | 2014.03.27 | N12W34 | plage | ||||||||
| 12021 | 2014.03.28 | 18 | 40 | 20 | S14E09 | 0160 | DAI | DAC |
 |
 |
area: 0450 |
| 12024 | 2014.03.28 2014.03.29 |
6 | N17W09 | 0014 | AXX |
 |
 |
location: N17W06 | |||
| S3276 | 2014.03.28 | 2 | S12E03 | 0006 | BXO |
 |
 |
||||
| S3277 | 2014.03.28 | 6 | S27E01 | 0015 | BXO | images/AR_S3277_20140331_2345.png |
 |
||||
| S3278 | 2014.03.28 | S17W19 | plage | ||||||||
| S3280 | 2014.03.28 | N09W13 | plage | ||||||||
| S3281 | 2014.03.29 | 1 | S07W51 | 0002 | AXX |
 |
 |
||||
| S3282 | 2014.03.29 | S18W58 | plage | ||||||||
| 12026 | 2014.03.30 | 13 | 27 | 13 | S11E64 | 0120 | DAI | DAC |
 |
 |
beta-gamma location: S11E67 area: 0200 |
| S3283 | 2014.03.30 | S25W83 |
 |
plage | |||||||
| 12027 | 2014.03.30 2014.03.31 |
1 | 2 | 1 | N13E69 | 0080 | HSX | HHX |
 |
 |
area: 0250 location: N12E71 |
| S3285 | 2014.03.30 | 1 | 1 | S10W23 | 0005 | HRX |
 |
 |
|||
| S3287 | 2014.03.31 | 1 | 1 | S30W79 | 0006 | AXX |
 |
||||
| S3288 | 2014.03.31 | 1 | N05E58 | 0006 | AXX |
 |
|||||
| S3289 | 2014.03.31 | 4 | 3 | S08E77 | 0060 | CAO |
 |
||||
| S3290 | 2014.03.31 | 1 | S20E42 | 0002 | AXX |
 |
|||||
| Total spot count: | 49 | 109 | 48 | ||||||||
| Sunspot number: | 129 | 259 | 148 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 82 | 148 | 87 | (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): | 77 | 91 | 81 | k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number) | |||||||
| Month | Average solar flux | International sunspot number (WDC-SILSO) |
Smoothed sunspot number | Average ap (3) |
|
|---|---|---|---|---|---|
| Measured | 1 AU | ||||
| 2013.01 | 127.1 | 123.1 | 62.9 | 58.7 (-0.9) | 4.69 |
| 2013.02 | 104.3 | 101.8 | 38.0 | 58.4 (-0.3) | 6.11 |
| 2013.03 | 111.3 | 110.2 | 57.9 | 57.5 (-0.9) | 10.56 |
| 2013.04 | 124.8 | 125.9 | 72.4 | 57.9 (+0.4) | 5.40 |
| 2013.05 | 131.4 | 134.3 | 78.7 | 59.9 (+2.0) | 9.73 |
| 2013.06 | 110.1 | 113.7 | 52.5 | 62.6 (+2.7) | 12.60 |
| 2013.07 | 115.5 | 119.3 | 57.0 | 65.5 (+2.9) | 9.47 |
| 2013.08 | 114.6 | 118.3 | 66.0 | 69.0 (+3.5) | 8.27 |
| 2013.09 | 102.6 | 103.7 | 36.9 | 73.1 (+4.1) | 5.23 |
| 2013.10 | 132.1 | 131.2 | 85.6 | (74.9 projected, +1.8) | 7.71 |
| 2013.11 | 148.3 | 145.1 | 77.6 | (74.9 projected, -0.0) | 5.68 |
| 2013.12 | 147.7 | 143.1 | 90.3 | (74.4 projected, -0.5) | 4.68 |
| 2014.01 | 157.4 | 152.4 | 82.0 | (74.3 projected, -0.1) | 5.44 |
| 2014.02 | 170.3 (cycle peak) |
166.3 | 102.8 (cycle peak) | (73.7 projected, -0.6) | 10.70 |
| 2014.03 | 149.9 | 148.5 | 92.2 | (73.8 projected, +0.1) | 4.9 |
| 2014.04 | (1) | (2A/2B) / 112.3 (2C) | (73.0 projected, -0.8) | () | |
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.
