[Ips-dsgr] IPS Daily Report - 29 May 03
rwc
rwc at ips.gov.au
Fri May 30 09:34:32 EST 2003
SUBJ: IPS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 29/2330Z MAY 2003 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 29 MAY AND FORECAST FOR 30 MAY - 01 JUNE
STATUS INDICATORS SOL:** RED ** MAG:** RED ** ION: ** RED **
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1A. SOLAR SUMMARY
Activity 29 May: High
Flares Max Fadeout Freq. Sectors
X1.1/2B 0105UT probable all West Pacific
M2.7/1N 1937UT possible lower East Pacific/
North American
M1.5/1F 0217UT possible lower E. Asia/Aust.
Observed 10.7 cm flux/Equivalent Sunspot Number for 29 May: 138/92
1B. SOLAR FORECAST
30 May 31 May 01 Jun
Activity Moderate to high Moderate to high Moderate to high
Fadeouts Probable Probable Probable
10.7cm/SSN 145/99 140/94 135/89
COMMENT: Two coronal mass ejections have struck the Earth. However,
there may be some ambiguity as to solar event origin. Two
M flare halo CME's were observed on 26 May, and two X flare CME's
were observed 27/28 May. Either the X class events have arrived
earlier than expected (arrival time estimate based on observed
radio Type II speeds) and the M class shocks were not discernable
in the solar wind, or these CME's are associated with the earlier
M class flares, and two more CME's are still enroute to the Earth.
An earlier than expected arrival of the X class CME's scenario is
more probable due to enhanced background solar wind speed due to
coronal hole high speed wind stream. The first small shock arrived
around 12UT, the second larger shock was at 1830UT on 29 May. Solar wind speed
increased from 650 to 750km/sec across the two shocks. The north-south
component of the interplanetary magnetic field fluctuated strongly
southward at shock arrival, reaching 40nT south around 19UT. Bz
then returned to near neutral/mildly southward. Also, the magnetopause
-the balancing point of the Earth's magnetic field and solar
wind pressure, crossed geosynchronous orbit at times between
19 and 22UT. Solar region 365 produced the most recent X1 event
and region 368 the M2 event, and again both were associated with
Type II/IV radio sweeps (inferred CME). The Type II shock speeds for
these events suggest that the X1 shock should arrival first half UT day
31 May, and the M2 shock should arrive first half 02 Jun. However, based
on recent estimated/observed arrival times these shocks may also
arrive earlier than expected. Dependant on solar origin of recent
shock arrivals, between 2 and 4 mass ejections could be on the
way to the Earth (2 is more likely scenario). Solar region 365
has been reported to have shown some signs of decay, but still
remains M and X class flare capable. Shortwave fadeouts can be
expected on daylight HF circuits. The large coronal hole visible
in SOHO imagery is approaching solar central meridian, high speed
wind stream entry expected 02 Jun.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 29 May: Unsettled to Severe Storm Levels
Estimated Indices 29 May : A K
Australian Region 50 4334 5677
Darwin 43 5333 5666
Townsville 40 3334 5666
Learmonth 40 3334 5666
Canberra 50 3344 5677
Hobart 45 3344 5577
Casey(Ant) 73 4433 5787
Observed Regional daily pc3 Indices 29 MAY :
Townsville 2 (Quiet)
Learmonth 27 (Quiet to unsettled)
Canberra 96 (Minor storm)
Hobart 76 (Active)
Estimated AFr/Ap Indices 29 May : A
Fredericksburg 50
Planetary 60
Observed AFr/Ap Indices 28 May : A K
Fredericksburg 22
Planetary 36 6555 4444
2B. MAGNETIC FORECAST
Date Ap Conditions
30 May 40 Initially at minor storm levels then declining.
31 May 60 Major storm
01 Jun 20 Active to minor storm
COMMENT: IPS Geomagnetic Warning 20 was issued on 29 May and
is current for interval 30-31 May. It appears that the mass ejections
from the recent X class events have arrivaed earlier than expected
with geomagnetic storm activity observed second half of UT day
on 29 May. Storm activity is likely to continue during first
half of UT day today then decline. Further mass ejection arrivals
are expected 31 May and 02 Jun, with major storm conditions likely
on 31 May due to the X class flare/CME on early on 29 May. In
addition coronal hole high speed wind stream effects expected
from 02 Jun.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
29 May Normal-fair Normal-poor Fair-poor
PCA Event : 10Mev Proton/PCA Event Began 29 05 2003 0155UT and is in progress
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
30 May Fair Fair-poor Poor
31 May Fair Fair-poor Poor
01 Jun Normal Fair Poor-fair
COMMENT: HF conditions very degraded late in UT day due to earlier
than expected arrival of mass ejections and geomagnetic storm
onset. High latitude HF communication also degraded due to proton
event in progress. High latitude communication expected to be
very degraded next two days. Further mass ejection arrival expected
31 May.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
29 May 73
Observed Australian Regional MUFs
Equatorial PNG Region:
Enhanced by 20% during local day,
Enhanced by 40% during local night,
Enhanced by 70% after local dawn.
Northern Australian Region:
Enhanced by 35% during local day,
Enhanced by 30% during local night.
Darwin MUfs were enhanced over 100% between 07 and 11 UT.
Southern Australian and New Zealand Region:
Mostly near predicted monthly values,
Depressed by 35% after local dawn.
Antarctic Region (Casey/Scott Base):
Proton event in progress, increased absorption observed.
Predicted Monthly T index for May: 72
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
30 May 70 near predicted monthly values (Northern Aus)
30 May 40 depressed 10 to 30% (southern Aus/NZ)
31 May 30 near predicted monthly values/depressed 10 to 30%
01 Jun 60 depressed 10 to 15%/near predicted monthly values
COMMENT: IPS HF Communications Warning 39 was issued on 28 May
and is current for interval 28-30 May. Geomagnetic storm activity
arrived earlier than expected, with storm onset late on 29 May.
Stations south of Townsville, are depressed by up to 30% after
local dawn this morning. Depressed conditins expected to continue
for most of local day, with a recovering trend. Further degraded
and depressed conditions are expected on 31 May/01 June, due
to the anticipated arrival of another mass ejection associated
with an X1 flare early on 29 May. Mid to high latitude HF comms
are expected to be very degraded over the next two days.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 28 May
Daily Proton Fluence >1 MeV: 1.7E+07
Daily Proton Fluence >10 MeV: 2.6E+05
Daily Electron Fluence >2 MeV: 3.10E+07 (normal)
X-ray background: B5.9
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
ACE Satellite Solar Wind Day Averaged Data for 28 May
Speed: 705 km/sec Density: 3.0 p/cc Temp: 208000 K Bz: 2 nT
(Courtesy Space Environment Center, Boulder USA)
ACE data can be incorrect during strong proton events.
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