[Ips-dsgr] ASWFC Daily Report - 20 September 23 issued 2332 UT on 20 Sep 2023 [SEC=OFFICIAL]
rwc
rwc at ips.gov.au
Thu Sep 21 09:32:55 EST 2023
SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 SEPTEMBER 2023
FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE
SUMMARY FOR 20 SEPTEMBER AND FORECAST FOR 21 SEPTEMBER - 23 SEPTEMBER
STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN
ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx
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1A. SOLAR SUMMARY
Activity 20 Sep: R2
Flares Max Fadeout Freq. Sectors
M8.2 1419UT probable lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Sep: 156/110
1B. SOLAR FORECAST
21 Sep 22 Sep 23 Sep
Activity R0-R1,chance R2 R0-R1,chance R2 R0-R1,chance R2
Fadeouts Possible Possible Possible
10.7cm/SSN 155/109 152/107 153/108
COMMENT: Solar activity on UT day 20-Sep was R2, due to am impulsive
M8 flare from AR3435(N09E29, beta-gamma). From early in the UT
day on 20-Sep the eastern portion of the main spot of this region
appeared to be breaking up and some smaller spots have emerged
of opposite polarity to the north east of the region, possibly
suggesting initial decay or at least spot redistribution. Nearby
AR3438(N10E23, beta) initially showed both growth and decay,
with an increase in trailer spots, but from late in the UT day
the largest spot decreased in area. Solar region AR3437(S17W41,
beta) continues to grow, with intermediate spot development evident.
A small new solar region AR3442(S09E61, beta) which was initially
a single small spot, is now showing numerous small trailer spots
that appear to be both emerging and decaying. Solar region AR3436(N21W58,
beta) is in decay. Other regions are relatively minor. There
are currently eleven numbered solar regions on the visible solar
disk. Solar activity is expected to be R0-R1 with a chance for
R2 over 21-23 Sep. In GONG H-alpha imagery, a solar filament
located at N28W60-70 lifted off during 20/0315-0428UT, and a
smaller filament located at N25E35 lifted off during 20/0153-0346UT.
No Earth directed CMEs have been observed. In LASCO C2, an eastward
CME was observed from 20/0648UT, a narrow north west directed
CME from 20/0824UT. a south east directed CME from 20/1524UT.
The timing of the filament eruptions did not correlate with CME
activity. The solar wind speed on UT day 20-Sep declined, ranging
from 451 to 562 km/sec and is currently near 450km/sec. The peak
total interplanetary magnetic field strength (IMF, Bt) was 11
nT and the north-south IMF component (Bz) range was 4 to -5 nT.
A small equatorial coronal hole located at solar longitude W20
may increase solar wind speeds slightly from mid 21-Sep to 23-Sep.
Another small coronal hole is located at the solar central meridian
at solar latitude N40.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 20 Sep: G0
Estimated Indices 20 Sep : A K
Australian Region 9 22332123
Cocos Island 6 22222122
Darwin 9 22332123
Townsville 9 22332123
Learmonth 14 33332134
Alice Springs 9 22332123
Gingin 12 23322234
Canberra 8 22322123
Hobart 10 23332123
Estimated Antarctic Regional K Indices 20 Sep :
Macquarie Island 20 13454333
Casey 12 24322133
Mawson 37 34433375
Observed Regional daily pc3 Indices 20 Sep :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 0 (Quiet)
Alice Springs 0 (Quiet)
Gingin 7 (Quiet)
Canberra 21 (Quiet to unsettled)
Hobart 46 (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 20 Sep : A
Fredericksburg 12
Planetary 16
Observed AFr/Ap Indices 19 Sep : A K
Fredericksburg 38
Planetary 38 6744 5543
2B. MAGNETIC FORECAST
Date Ap Conditions
21 Sep 10 G0
22 Sep 16 G0, slight chance of G1
23 Sep 12 G0
COMMENT: G0 geomagnetic conditions were observed in the Australian
region on UT day 20-Sep. In the Antarctic region an isolated
period of G1 was observed at Macquarie Island and a period of
G1 and G3 was observed at Mawson. G0 conditions were observed
at Casey. G0 geomagnetic conditions are generally expected on
21-23 Sep, with a wind stream from a small coronal inducing a
mild increase in geomagnetic activity expected on 22-Sep.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
20 Sep Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
21 Sep Normal Fair-normal Fair-normal
22 Sep Normal Normal-fair Fair
23 Sep Normal Fair-normal Fair-normal
COMMENT: HF radio propagation conditions on UT day 20-Sep were
normal. Mildly degraded HF conditions may be experienced after
local dawn on 21-Sep. Mildly degraded conditions are possible
during local night hours on 22-Sep for middle to high latitudes.
Isolated fadeouts possible.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
20 Sep 99
Observed Australian Regional MUFs
Cocos Island Region:
Enhanced by 30% during local day.
Depressed by 30% during local night.
Niue Island Region:
Mostly near predicted monthly values.
Enhanced by 30% after local dawn.
Northern Australian Region:
Enhanced by 15% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Near predicted monthly values.
Depressed 15% after local dawn.
Antarctic Region (Casey/Davis/Mawson):
Depressed by 25% over the UT day.
Monthly T index:
Month T index
Aug 115
Sep 96
Oct 93
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
21 Sep 80 Depressed 10 to 15%/near predicted monthly values
22 Sep 95 Near predicted monthly values
23 Sep 95 Near predicted monthly values
COMMENT: ASWFC SWF HF Communications Warning 96 was issued on
20 September and is current for 20-22 Sep. ASWFC HF Communications
Warning 97 was issued on 20 September and is current for 21 Sep
only. Maximum usable frequencies (MUFs) in the Australian region
on UT day 20-Sep were mostly near predicted values to 15% enhanced.
Spread-F was observed at Hobart during local night hours. MUFs
have been depressed 15% after local dawn this morning for the
southern Australian region. Mild ionospheric phase scintillation
(<1 deg.) was observed at Weipa during the interval 20/08-12UT.
MUFs are expected to be depressed 15% to near predicted monthly
values on 21-Sep and generally near predicted monthly values
for 22-23 Sep. Mild degradations may be experienced during local
night hours on 22-Sep due to anticipated mild geomagnetic activity
from a coronal hole wind stream. There is a chance for further
brief mild depressions after local dawn on 23-Sep in the southern
Australian region. Isolated fadeouts possible.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 19 Sep
Daily Proton Fluence >1 MeV: 5.4E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 3.30E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 5%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: C1.2
DSCOVR Satellite Solar Wind Day Averaged Data for 19 Sep
Speed: 574 km/sec Density: 0.2 p/cc Temp: 89100 K Bz: -3 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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