[Ips-dsgr] IPS Daily Report - 27 April 06
rwc
rwc at ips.gov.au
Fri Apr 28 09:38:33 EST 2006
SUBJ: IPS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 27/2330Z APRIL 2006 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 27 APRIL AND FORECAST FOR 28 APRIL - 30 APRIL
STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN
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1A. SOLAR SUMMARY
Activity 27 Apr: High
Flares Max Fadeout Freq. Sectors
M7.9 1552UT probable lower South American/
Atlantic
Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Apr: 101/49
1B. SOLAR FORECAST
28 Apr 29 Apr 30 Apr
Activity Low to moderate Low to moderate Low to moderate
Fadeouts Possible Possible Possible
10.7cm/SSN 100/48 100/48 100/48
COMMENT: Solar activity has again been low to moderate over the
UT day. Region 875 has still provided all the flare activity
with an M7.9 at ~1530UT against a background of four B class
flares. A higher peak activity against a lower background than
yesterday. The SOHO spacecraft LASCO instrument did not appear
to show a CME due to the M7.9 flare. AR875 is still east of solar
central meridian so CMEs are not very likely be Earth directed.
AR875 exhibited activity around it's rim and still has the potential
for large C and M class flares as it rotates into geoeffective
position in the next few days. Trailing regions 876 and 877 have
not exhibited flare activity. The solar wind varied between 310
and 350 km/sec and is trending low at 310km/s near 23UT.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 27 Apr: Quiet
Estimated Indices 27 Apr : A K
Australian Region 3 21101111
Darwin 3 21101111
Learmonth 3 21111111
Culgoora 1 11101001
Camden 4 21112112
Canberra 1 11001001
Hobart 2 11101101
Casey(Ant) 4 22211111
Observed Regional daily pc3 Indices 27 Apr :
Canberra 11 (Quiet)
Learmonth 0 (Quiet)
Culgoora 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.
Estimated AFr/Ap Indices 27 Apr : A
Fredericksburg 4
Planetary 5
Observed AFr/Ap Indices 26 Apr : A K
Fredericksburg 2
Planetary 5 2211 1121
2B. MAGNETIC FORECAST
Date Ap Conditions
28 Apr 4 Quiet
29 Apr 4 Quiet
30 Apr 5 Quiet
COMMENT: Geomagnetic activity was quiet over the UT day. Major
coronal holes are not in evidence on the solar disc and solar
wind speed is low, declining to 310 km/sec, suggesting little
viscous interaction with the geomagnetic field. Solar interplanetary
magnetic field (IMF) Bz component observed on the ACE spacecraft
only showed sustained southward orientation from 00-04UT and
12-15UT. This was only long enough to slightly excite high latitudes
and not the global magnetic field. Expect quiet geomagnetic conditions
for the next 3 days, unless further M class flares from AR875
produce geoeffective CMEs or an extended period of IMF Bz southwards
(>12hrs) occurs.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
27 Apr Normal-fair Normal Normal
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
28 Apr Normal Normal Normal
29 Apr Normal Normal Normal
30 Apr Normal Normal Normal
COMMENT: Mostly normal HF conditions observed at mid and high
latitudes. Low latitudes appeared to be disturbed and enhanced
across the local night although there was significant geographic
variation in the conditions. High latitudes exhibited typical
spread winter, low solar input, conditions with minor disturbances,
probably due to the two periods of 3-5hour IMF Bz southwards
moderately enhancing polar convection. These conditions are expected
to continue in the absence of major M class flaring activity
from AR875 or sustained IMF Bz southward conditions.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
27 Apr 31
Observed Australian Regional MUFs
about 15% above predicted monthly values
Predicted Monthly T index for April: 16
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
28 Apr 31 10 to 25% above predicted monthly values
29 Apr 31 10 to 25% above predicted monthly values
30 Apr 32 10 to 25% above predicted monthly values
COMMENT: Mostly normal HF conditions observed over the UT day.
Some low latitude stations again observed nighttime enhancements,
including pre-dusk or pre-dawn bulges depending on location.
PNG sector seemed to most affected with strong nightime absorption
also observed at Vanimo. Strong sporadic activity observed over
NZ pre-dawn. High latitudes near the polar cap appeared enhanced.
Mostly normal HF conditions expected for the next three days
with a slightly strengthening ionosphere due to extra ionising
solar radiation from active regions 875,876 and 877. MUFs generally
above predicted monthly values by 10-25%.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 26 Apr
Daily Proton Fluence >1 MeV: 2.4E+05
Daily Proton Fluence >10 MeV: 1.7E+04
Daily Electron Fluence >2 MeV: 1.10E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 2%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: B1.4
ACE Satellite Solar Wind Day Averaged Data for 26 Apr
Speed: 355 km/sec Density: 1.7 p/cc Temp: 60300 K Bz: 0 nT
(Courtesy Space Environment Center, Boulder USA)
ACE data can be incorrect during strong proton events.
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