[Ips-dsgr] ASWFC Daily Report - 31 August 23 issued 2330 UT on 31 Aug 2023 [SEC=OFFICIAL]
Regional Warning Centre
rwc at ips.gov.au
Fri Sep 1 09:30:08 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/31 AUGUST 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 31 AUGUST AND FORECAST FOR 01 SEPTEMBER - 03 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 31 Aug: R0
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 31 Aug: 140/94
1B. SOLAR FORECAST
01 Sep 02 Sep 03 Sep
Activity R0-R1, chance R2 R0-R1, chance R2 R0-R1, chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 140/94 150/105 150/105
COMMENT: Solar activity on UT day 31-Aug was R0, with the most
significant event being a long-duration C2 flare from AR3413
(N09W59, beta-gamma). There are currently five numbered sunspot
regions on the solar disk. AR3413 continues to be the most magnetically
complex region, and has shown some growth over the past 24 hours.
AR3415 (S07W52, beta) has also shown some minor growth but has
remained quiet. Solar activity is expected to be R0-R1 with a
chance for R2 over 01-03 Sep mainly due to AR4313, however this
region is due to rotate over the western limb by the end of the
period.
A CME was observed in association with a filament eruption
from 30/2212 UT and has now been analysed to likely have a geoeffective
component. The CME is expected to arrive by 02/1800 UT +/- 12
hours, although there is bias towards a later arrival but overall
low confidence on the arrival time. Another CME was observed
from 31/0336 UT but is not expected to be geoeffective. No other
CMEs were observed on this day. The solar wind speed on UT day
31-Aug was steady near 330 km/s, until 31/1630 UT when it increased
to around 400 km/s. The peak total interplanetary field strength
(IMF, Bt) was 12 nT and the north-south IMF component (Bz) range
was +10 to -7 nT. The solar wind speed is expected to remain
near 350-400 km/s over 01-02 Sep, then increase late on 02-Sep
due to the arrival of a CME first observed on 30-Aug. A small
coronal hole wind stream may further increase solar wind speeds
by 03-Sep.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 31 Aug: G0
Estimated Indices 31 Aug : A K
Australian Region 4 12210221
Cocos Island 3 11210120
Darwin 5 12111222
Townsville 6 12221222
Learmonth 4 12210221
Alice Springs 4 11210222
Gingin 3 11210220
Canberra 4 12120211
Hobart 4 12220211
Estimated Antarctic Regional K Indices 31 Aug :
Macquarie Island 3 01130100
Casey 8 33310222
Mawson 14 23310154
Observed Regional daily pc3 Indices 31 Aug :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Hobart 0 (Quiet)
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 31 Aug : A
Fredericksburg 6
Planetary 6
Observed AFr/Ap Indices 30 Aug : A K
Fredericksburg 9
Planetary 6 21122121
2B. MAGNETIC FORECAST
Date Ap Conditions
01 Sep 6 G0
02 Sep 16 G1-G2, chance G3
03 Sep 24 G1-G2, chance G3
COMMENT: ASWFC Geomagnetic Warning 47 was issued on 31 August
and is current for 2-3 Sep. G0 geomagnetic conditions were observed
in the Australian region on UT day 31-Aug. Mostly G0 geomagnetic
conditions were observed in the Antarctica region, with an isolated
period of G1 at Mawson. G0 geomagnetic conditions are expected
on 01-Sep. G1-G2 geomagnetic conditions, with a chance for G3,
are expected by 1800 UT +/- 12 hours on 02-Sep due to an anticipated
impact from a CME. Geomagnetic conditions from this event are
likely to continue into 03-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
31 Aug Normal Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
01 Sep Normal Normal Normal
02 Sep Normal Normal-fair Fair
03 Sep Normal-fair Fair Fair
COMMENT: HF radio propagation conditions on UT day 31-Aug were
mostly good. Normal HF propagation conditions are expected on
01-Sep, but some degradations are likely by late 02-Sep and 03-Sep
due to anticipated geomagnetic activity.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
31 Aug 111
Observed Australian Regional MUFs
Cocos Island Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Niue Island Region:
Enhanced by 15% during local day.
Enhanced by 70% during local night.
Northern Australian Region:
Near predicted monthly values during local day.
Enhanced by 35% during local night.
Southern Australian Region:
Near predicted monthly values during local day.
Enhanced by 20% during local night.
Antarctic Region (Casey/Davis/Mawson):
Enhanced by 20% over the UT day.
Monthly T index:
Month T index
Jul 103
Aug 88
Sep 84
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
01 Sep 105 Near predicted monthly values to 15-20% enhanced
02 Sep 105 Near predicted monthly values
03 Sep 95 Near predicted monthly values to 15-20% depressed
COMMENT: ASWFC Preliminary HF Communications Warning 84 was issued
on 31 August and is current for 3-4 Sep. Maximum usable frequencies
(MUFs) on UT day 31-Aug were near predicted values to 35% enhanced
in the Australian region. Range spread was observed at Niue Island
during local night hours. Scintillation was observed at Niue
and Weipa from 31/0801-1134 UT. MUFs are expected to be near
predicted values over 01-02 Sep to 20% enhanced, but by 03-Sep
are expected to become depressed by 15-20% due to anticipated
geomagnetic activity. Degradations are likely by late UT day
02-Sep and 03-Sep.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 30 Aug
Daily Proton Fluence >1 MeV: 5.8E+04
Daily Proton Fluence >10 MeV: 1.8E+04
Daily Electron Fluence >2 MeV: 1.50E+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 30 Aug
Speed: 326 km/sec Density: 2.5 p/cc Temp: 50500 K Bz: 0 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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