[Ips-dsgr] ASWFC Daily Report - 01 September 23 issued 2330 UT on 01 Sep 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Sat Sep 2 09:30:45 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/01 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 01 SEPTEMBER AND FORECAST FOR 02 SEPTEMBER - 04 SEPTEMBER
STATUS INDICATORS SOL:GREEN MAG:** RED ** ION: ** YELLOW **
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 01 Sep: R1
Flares Max Fadeout Freq. Sectors
M1.1 0319UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 01 Sep: 136/90
1B. SOLAR FORECAST
02 Sep 03 Sep 04 Sep
Activity R0,chance R1 R0,chance R1 R0
Fadeouts None expected None expected None expected
10.7cm/SSN 135/89 135/89 130/84
COMMENT: Solar activity on UT day 01-Sep was R1, due to a long
duration M1 flare from solar region AR3413(N09W70, beta). A large
west directed semi halo CME was associated with this event, however
due to the regions far western solar longitude location (W62)
at the time of the flare, subsequent event modelling does not
show a significant Earth directed component from this CME. This
flare was followed by an S1-Minor proton event 01/0425-2000UT.
Solar activity is expected to be predominately R0 02-04 Sep,
with a chance for an isolated R1 flare over 02-03 Sep due to
AR4313, which is showing decay and will soon rotate off disk.
There are currently 5 solar regions on the disk which are either
stable or in decay. No new significantly Earth directed CMEs
were observed on 01-Sep. The solar wind speed on UT day 01-Sep
was steady near 400 km/s, until 01/1800 UT when it increased
to around 500 km/s. It is uncertain whether this increase is
an instrument issue or actual variation. The peak total interplanetary
field strength (IMF, Bt) was 11 nT and the north-south IMF component
(Bz) range was +9 to -10 nT. The IMF Bz component was frequently
orientated mildly southward during the interval 01/03-13UT. A
solar wind shock arrival is expected on 02-Sep due to a CME observed
late on 30-Aug associated with a solar filament eruption. A small
coronal hole is located at solar latitude N40 at the solar central
meridian.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 01 Sep: G0
Estimated Indices 01 Sep : A K
Australian Region 9 23233221
Cocos Island 6 22222211
Darwin 7 23223111
Townsville 9 23233212
Learmonth 9 32233221
Alice Springs 7 23223111
Gingin 10 32233222
Canberra 9 13233221
Hobart 9 23233221
Estimated Antarctic Regional K Indices 01 Sep :
Macquarie Island 15 12345311
Casey 10 34232112
Mawson 24 44433254
Observed Regional daily pc3 Indices 01 Sep :
Darwin 0 (Quiet)
Townsville 2 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 2 (Quiet)
Gingin 3 (Quiet)
Canberra 22 (Quiet to unsettled)
Hobart 31 (Quiet to unsettled)
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 01 Sep : A
Fredericksburg 12
Planetary 12
Observed AFr/Ap Indices 31 Aug : A K
Fredericksburg 8
Planetary 6 1222 1122
2B. MAGNETIC FORECAST
Date Ap Conditions
02 Sep 25 Initially G0, G1-G2 second half of UT day.
03 Sep 30 G1-G2 first half of UT day.
04 Sep 18 G0-G1. Isolated G1 periods possible first half
of UT day.
COMMENT: ASWFC Geomagnetic Warning 48 was issued on 1 September
and is current for 2-4 Sep. G0 geomagnetic conditions were observed
in the Australian region on UT day 01-Sep. G0 geomagnetic conditions
were generally observed in the Antarctica region, with isolated
periods of G1 at Mawson and Macquarie Island. G1-G2 geomagnetic
conditions, with a chance for G3, are expected over 02-03-Sep,
due to an anticipated impact from a CME.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
01 Sep Normal Normal Normal-fair
PCA Event : 10MeV Proton/PCA Event Began at 0425UT 01/09, Ended at 2000UT 01/09
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
02 Sep Normal Normal-fair Fair-poor
03 Sep Normal Fair Poor-fair
04 Sep Normal Fair-normal Fair
COMMENT: HF radio propagation conditions on UT day 01-Sep were
mostly normal. Degraded conditions are likely by mid 02-Sep and
on 03-Sep due to anticipated geomagnetic activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
01 Sep 117
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Depressed by 15% during local night.
Niue Island Region:
Enhanced by 15-40%.
Northern Australian Region:
Enhanced by 20%.
Southern Australian Region:
Enhanced by 15-20%.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 15% over the UT day.
Monthly T index:
Month T index
Aug 115
Sep 84
Oct 81
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
02 Sep 105 Initially near predicted monthly values to 15%
enhanced
03 Sep 60 Depressed 15 to 20%/near predicted monthly values
04 Sep 75 Depressed 10 to 15%/near predicted monthly values
COMMENT: ASWFC Preliminary HF Communications Warning 84 was issued
on 31 August and is current for 3-4 Sep. ASWFC SWF HF Communications
Warning 85 was issued on 1 September and is current for 1-3 Sep.
Maximum usable frequencies (MUFs) on UT day 01-Sep were near
predicted values to 20% enhanced in the Australian region. Scintillation
was observed at Niue and Weipa from 01/1200-1300UT. A minor fadeout
only impacting the ionospheric E region was observed in association
with the M1.2 flare. MUFs are initially expected to be near predicted
values on 02-Sep to 15% enhanced, becoming 15-20% depressed on
03-Sep due to anticipated geomagnetic activity. Depending on
geomagnetic storm onset time and magnitude depressions may extend
into 04-Sep. Degraded HF conditions are likely during local night
hours for southern Australian region 02-Sep and 03-Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 31 Aug
Daily Proton Fluence >1 MeV: 2.3E+05
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 1.20E+06 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B6.0
DSCOVR Satellite Solar Wind Day Averaged Data for 31 Aug
Speed: 328 km/sec Density: 4.6 p/cc Temp: 49600 K Bz: 2 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Australian Space Weather Forecasting Centre
Bureau of Meteorology
ASWFC at bom.gov.au
www.bom.gov.au | www.sws.bom.gov.au
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