Solar Terrestrial Activity Report

Last update December 2, 2002 at 03:50 UTC.

[Solar and geomagnetic data - last 4 weeks (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update December 2, 2002)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2002)]
[Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2002)]
[Historical solar and geomagnetic data charts 1954-2002 (last update October 13, 2002)]
[Archived reports (last update December 1, 2002)]

Recent activity

The geomagnetic field was unsettled to active on December 1. Solar wind speed ranged between 457 and 558 km/sec under the influence of a coronal stream.

Solar flare activity was low. Solar flux was 149.6, the planetary A index was 16 (STAR Ap - based on the mean of three hour ap indices: 17.1).
Three hour interval K indices: 43344333 (planetary), 33333422 (Boulder).

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

At midnight there were 5 spotted regions on the visible disk, 1 of which has not yet been numbered. A total of 6 C class events was recorded during the day.

Region 10205 decayed slowly and quietly. If the current rate of decay persists the region will become spotless tomorrow.
Region 10207 added a few spots but didn't change much otherwise. Only C class flares are likely at this time. Flare: C1.8 long duration event peaking at 16:51 UTC.
Region 10208 developed slowly and currently has mixed polarities. A minor M class flare is possible. Flares: C1.0 at 12:38 and C5.5 at 15:28 UTC.
Region 10209 decayed slowly and was mostly quiet. Flare: C1.7 at 03:58 UTC.
Region 10210 rotated out of view after noon. Flare: C1.3 at 02:35 UTC.

Spotted regions not yet numbered by SEC:
[S40] A new region emerged early in the day in the southeast quadrant. Location at midnight: S07E15.

Coronal mass ejections (CMEs)

November 29 - December 1: No obviously geoeffective CMEs noted.

Coronal holes

Coronal hole history (starting late October 2002)

A coronal hole in the northern hemisphere could move into a geoeffective position on December 4-5.

Processed SOHO EIT 284 image at 01:06 UTC on December 2. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on December 2-4. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very poor.

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)

Composite image based on a SOHO/MDI continuum image and overlaid by a coronal hole image. Region numbering has been included.

Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. Comments are my own, as is the STAR spot count (spots observed at or just prior to midnight) and data for regions not numbered by SEC or where SEC has observed no spots.

Solar region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10200 2002.11.20     S03W80     plage
10202 2002.11.24     N15W29     plage
10203 2002.11.26     N09E04     plage
10204 2002.11.27     N20W15     plage
10205 2002.11.27 1 1 N19E10 0020 HSX  
10206 2002.11.27   S27W09     plage
10207 2002.11.27 20 26 S19E20 0230 EAI  
10208 2002.11.29 16 23 N10E49 0140 DSO beta-gamma
classification was DAI
at midnight
10209 2002.11.30 7 11 S21E48 0170 EAO  
10210 2002.11.30 3   S08W87 0060 DSO rotated out of view
S40 emerged on
2002.12.01
  4 S07E15 0020 CSO  
Total spot count: 47 65
SSN: 97 115

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
2001.11 210.6 106.5 115.5 (+1.5)
2001.12 235.1 132.2 114.6 (-0.9)
2002.01 226.6 114.1 113.5 (-1.1)
2002.02 205.0 107.4 114.7 (+1.2)
2002.03 179.5 98.4 113.4 (-1.3)
2002.04 189.8 120.7 110.5 (-2.9)
2002.05 178.4 120.8 108.8 (-1.7)
2002.06 148.7 88.3 (106.4 predicted, -2.4)
2002.07 173.5 99.9 (102.8 predicted, -3.6)
2002.08 183.6 116.4 (99.6 predicted, -3.2)
2002.09 175.8 109.3 (96.6 predicted, -3.0)
2002.10 167.0 97.5 (93.1 predicted, -3.5)
2002.11 168.7 95.0 (87.8 predicted, -5.3)
2002.12 149.6 (1) 3.1 (2) (83.5 predicted, -4.3)

1) Running average based on the daily 20:00 UT observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% 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. Comments and suggestions are always welcome.


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