[Ips-dsgr] SWS Daily Report - 20 April 20 issued 2334 UT on 20 Apr 2020
rwc
rwc at ips.gov.au
Tue Apr 21 09:34:18 EST 2020
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 APRIL 2020 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 20 APRIL AND FORECAST FOR 21 APRIL - 23 APRIL
STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN
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1A. SOLAR SUMMARY
Activity 20 Apr: Very low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr: 68/2
1B. SOLAR FORECAST
21 Apr 22 Apr 23 Apr
Activity Very low Very low Very low
Fadeouts None expected None expected None expected
10.7cm/SSN 69/3 69/3 69/3
COMMENT: Solar activity was very low on UT day, 20 April. Very
low levels of solar activity are expected for the next three
UT days, 21-23 April. The visible disc has been spotless and
there are no returning regions expected. No Earth bound CMEs
observed in available LASCO and STEREO images. The day started
with the solar wind parameters at nominal levels, but a weak
shock was observed in the solar wind at 0130UT. Post shock, the
solar wind suddenly increased from 295 km/s to 330 km/s and reached
a peak of 388 km/s at 0826 UT. During the later hours of the
day the solar wind speed gradually decreased to around 330 km/s
by 2300 UT. The total IMF (Bt) was initially between 3 nT and
6 nT. Post shock, Bt increased up to around 16 nT. The north-south
IMF component (Bz) ranged from -5 nT to +7 nT until around 0630
UT, then went negative up to -15 nT and stayed negative until
1330 UT. Bz then turned positive and rose up to +13 nT. The solar
wind particle density was around 3 ppcc before the shock and
postshock it increased to 10 ppcc and rose up to around 35 ppcc.
After 0730 UT, the particle density varied between 6 and 14 ppcc.
The shock may have arrived because of the unexpected glancing blow of a
slow CME that was observed on UT day 15 April. Solar wind parameters
may show minor to moderate strengthening on UT day 21 April and
minor strengthening on 22 and 23 April.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Apr: Quiet to Minor
Storm
Estimated Indices 20 Apr : A K
Australian Region 13 22335300
Darwin 13 33334301
Townsville 15 33335301
Learmonth 14 32335300
Alice Springs 13 22335301
Gingin 13 22335300
Canberra 9 22334200
Hobart 14 22345300
Estimated Antarctic Regional K Indices 20 Apr :
Macquarie Island 36 21567300
Casey 14 34333312
Mawson 16 24433323
Observed Regional daily pc3 Indices 20 Apr :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 2 (Quiet)
Alice Springs 0 (Quiet)
Gingin 2 (Quiet)
Canberra 4 (Quiet)
Melbourne NA
Pc3 pulsations are high frequency (10-45 second period) variations
of the Earths magnetic field. Daily pc3-indices are the daily sum
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data.
NOTE: Indices may have been generated from data obtained in
cooperation with the following organisations: Geoscience Australia,
University of Newcastle Space Physics Group, Australian Government
Antarctic Division and International Center for Space Weather
Science and Education, Japan.
Estimated AFr/Ap Indices 20 Apr : A
Fredericksburg 15
Planetary 20
Observed AFr/Ap Indices 19 Apr : A K
Fredericksburg 2
Planetary 5 1001 2322
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Apr 12 Mostly unsettled, isolated active periods possible
22 Apr 10 Quiet to Unsettled
23 Apr 10 Quiet to Unsettled
COMMENT: SWS Geomagnetic Warning 2 was issued on 20 April and
is current for 20-21 Apr. In the SWS magnetometer data for 20
Apr, a weak (10nT) impulse was observed at 0232UT. On UT day
20 April, the geomagnetic conditions in the Australian and Antarctic
regions varied from quiet to minor storm levels. Short periods
of isolated major storm were also recorded in the Antarctic region.
Global geomagnetic conditions may vary from unsettled to active
levels on UT day 21 April and quiet to unsettled levels on 22
and 23 April.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Apr Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Apr Normal Normal Normal-fair
22 Apr Normal Normal Normal
23 Apr Normal Normal Normal
COMMENT: Maximum usable frequencies (MUFs) were near predicted
monthly values with periods of minor to significant enhancements
on UT day, 20 Apr. Nearly similar HF conditions may be expected
on UT days 22 and 23 April. However, minor MUF depressions may
be observed on UT day 21 April.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Apr 1
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 25% during local day.
Enhanced by 105% during local night.
Niue Island Region:
No data available during local day.
No data available during local night.
Enhanced by 45% after local dawn.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 45% during local night.
Enhanced by 35% after local dawn.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 25% during local night.
Enhanced by 20% after local dawn.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Near predicted monthly values over the UT day.
Monthly T index:
Month T index
Mar 1
Apr -14
May -14
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 Apr -5 Near predicted monthly values/depressed 10 to
20%
22 Apr 0 Near predicted monthly values
23 Apr 0 Near predicted monthly values
COMMENT: Maximum usable frequencies (MUFs) were near predicted
monthly values with periods of minor to significant enhancements
for the Australian region on UT day, 20 Apr. Nearly similar HF
conditions may be expected on UT days 22 and 23 April. However,
minor MUF depressions may be observed on UT day 21 April.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Apr
Daily Proton Fluence >1 MeV: 6.2E+04
Daily Proton Fluence >10 MeV: 4.7E+04
Daily Electron Fluence >2 MeV: 1.70E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: <A1.0
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Apr
Speed: 317 km/sec Density: 3.0 p/cc Temp: 16700 K Bz: 0 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Space Weather Services email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386 WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240 AUSTRALIA FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010 fax: +61 2 9213 8060
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