Solar Terrestrial Activity Report

Last update issued on July 14, 2003 at 04:20 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 2, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update April 13, 2003)]
[Archived reports (last update July 11, 2003)]

Recent activity

The geomagnetic field was quiet to active on July 13. Solar wind speed ranged between 488 and 646 km/sec, under the decreasing influence of a high speed stream from coronal hole CH47.

Solar flux measured at 20h UTC on 2.8 GHz was 126.5. The planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 15.3).
Three hour interval K indices: 33433323 (planetary), 43333433 (Boulder).

The background x-ray flux is at the class B5 level.

At midnight there were 10 spotted regions on the visible disk. Solar flare activity was low. A total of 6 C class events was recorded during the day.

Region 10401 developed as new flux emerged near the leader spots.
Region 10404 reemerged with a few spots. Flare: C1.4 at 01:20 UTC. This event was associated with an erupting filament in and to the north of the region.
Region 10405 developed slowly with most of the development occurring in the trailing spots.
Region 10406 was quiet and generally unchanged.
Region 10407 was quiet and stable.
New region 10408 emerged in the northeast quadrant early on July 12 and was numbered by SEC the next day.
New region 10409 rotated into view at the northeast limb on July 12 and was numbered by SEC the following day. This is a compact region with little separating the positive and negative polarity spots. Further C and minor M class flaring is likely. Flares: C1.0 at 11:00, C1.5 at 12:26, C1.1 at 19:50, C2.2 at 22:52 and C2.9 at 23:10 UTC.
New region 10410 rotated into view at the southeast limb on July 12 and was numbered by SEC the next day.

Spotted regions not numbered by SEC:
[S204] A new region emerged on July 13 to the northwest of region 10409. Apparently SEC has decided that this region is part of region 10409. In magnetograms this is clearly a separate region, and has been determined to be that by Mt.Wilson as well. Location at midnight: N17E62.
[S205] A new region emerged in the southwest quadrant on July 13 just southeast of region 10404. Location at midnight: S11W15.

Coronal mass ejections (CMEs)

July 12-13: No LASCO images available due to a problem with the SOHO high gain antenna.

July 11: The long duration C3 event in the morning near the center of the solar disk appears to have been associated with a slow CME. While best defined over the north pole, material outflow was observed over both the southeast and southwest limbs. The CME could reach Earth on July 14.

July 13: A filament eruption beginning at 00:32 UTC in spotless region 10404 and along the southern border of CH48 visibly affected the corona as far north as N20 (on the other side of coronal hole CH48) and areas well into the northwest quadrant. A CME was likely associated with this event. With an origin near the center of the solar disk the CME could easily become geoeffective.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent and developing coronal hole (CH48) in the northern hemisphere and with a significant trans equatorial extension will rotate into a geoeffective position on July 12-15.

Processed GOES SXI coronal structure image at 23:20 UTC on July 13. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet to active on July 14 until the possible arrival of a CME observed on July 11. If that CME arrives unsettled to minor storm conditions will be likely. A likely CME associated with a near center disk filament eruption early on July 13 could reach Earth late on July 15. The high speed stream from coronal hole CH48 will cause unsettled to minor storm conditions on July 15-18.

Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor. Propagation along north-south paths is fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: none, several stations from Uruguay and Argentina noted.]

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact 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 (Recent map)

Compare to the previous day's image.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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 SEC or where SEC has observed no spots.

Solar region Date numbered SEC
Location at midnight Area Classification Comment
10401 2003.07.06 19 24 S10W31 0170 DAO classification was DAI
at midnight
10403 2003.07.07     S16W26     plage
10404 2003.07.07 2 4 S08W20 0020 CSO classification was CRO
at midnight
10405 2003.07.11 10 16 S11E41 0090 CAO classification was DAO
at midnight
10406 2003.07.11 5 6 S18W37 0030 CSO classification was CAO
at midnight
10407 2003.07.11 3 5 N10E04 0010 CSO area was 0020
at midnight
10408 2003.07.13 5 9 N13E23 0020 CSO formerly region S201
10409 2003.07.13 11 12 N14E69
0250 EAO formerly region S203
location corrected
classification was DAC
at midnight
10410 2003.07.13 2 3 S13E63 0040 CSO formerly region S202
S199 emerged on
    S07W84     plage
S204 emerged on
  3 N17E62 0020 HSX  
S205 emerged on
  5 S11W15 0000 BXO  
Total spot count: 57 87
SSN: 137 187

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2002.06 148.7 88.3 106.2 (-2.6)
2002.07 173.5 99.6 102.7 (-3.5)
2002.08 183.6 116.4 98.7 (-4.0)
2002.09 175.8 109.6 94.6 (-4.1)
2002.10 167.0 97.5 90.5 (-4.1)
2002.11 168.7 95.5 85.2 (-5.3)
2002.12 157.2 80.8 82.0 (-3.2)
2003.01 144.0 79.7 (79.7 predicted, -2.3)
2003.02 124.5 46.0 (74.7 predicted, -5.0)
2003.03 131.4 61.1 (69.0 predicted, -5.7)
2003.04 126.4 60.0 (64.1 predicted, -4.9)
2003.05 115.7 55.2 (59.2 predicted, -4.9)
2003.06 129.3 77.4 (55.2 predicted, -4.0)
2003.07 130.2 (1) 54.4 (2) (51.6 predicted, -3.6)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.

[DX-Listeners' Club]