[Ips-dsgr] IPS Daily Report - 15 April 01

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SUBJ: IPS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 15/2330Z APRIL 2001 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 15 APRIL AND FORECAST FOR 16 APRIL - 18 APRIL
STATUS INDICATORS SOL:** YELLOW **   MAG:** YELLOW **     ION: ** YELLOW **
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1A. SOLAR SUMMARY
Activity 15 Apr:  High

Flares    Max     Fadeout    Freq.  Sectors
X14/2B    1350UT  probable   all    European

Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Apr: 134/88

GOES satellite data for 14 Apr
       Daily Proton Fluence >1 MeV:   4.1E+06
       Daily Proton Fluence >10 MeV:  1.7E+05
       Daily Electron Fluence >2 MeV: 6.50E+07 (normal)
       X-ray background: B5.1
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.

1B. SOLAR FORECAST
             16 Apr             17 Apr             18 Apr
Activity     Moderate to high   Moderate           Moderate to high
Fadeouts     Probable           Probable           Probable
10.7cm/SSN   145/99             150/105            160/114

COMMENT: 9415 produced the Y1.4 (X14) class event. This event 
was associated with a type II and IV radio sweeps, indicating 
a probable mass ejection. A strong proton event began at 1405UT, 
in association with the flare. A ground level event was reported 
on the Thule riometer, associated with the highly energetic protons 
from the solar flare. Ground level events (GLE's) are relatively 
rare, occuring only a few times each solar cycle. Whilst the 
flares large magnitude indicates good geoeffectiveness, the region
is now almost at the west limb, reducing storm effects of flare/mass 
ejection. Further flare activity is possible over the next day, 
then solar activity is expected to decline. However, a large previously 
flaring region (sec 9393) is due back around 18 Apr and if this 
region returns increased flare activity may be experienced after 
this date. 
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 15 Apr: Quiet to Unsettled 

Estimated Indices 15 Apr :  A   K           
   Australian Region        8   2232 3212
      Darwin                8   2232 3212
      Townsville            8   2232 3203
      Learmonth            11   2223 3-32
      Canberra             10   2232 4213
      Hobart               10   2232 4212
    
Observed Regional daily pc3 Indices 15 APR : 
      Darwin               15   (Quiet)
      Townsville            0   (Quiet)
      Learmonth             0   (Quiet)
      Canberra             59   (Unsettled)
      Hobart               69   (Active)
Estimated AFr/Ap Indices 15 Apr : A 
           Fredericksburg        15
           Planetary             15                         

Observed AFr/Ap Indices 14 Apr :  A   K
           Fredericksburg        13
           Planetary             15   3343 3332     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
16 Apr    15    Unsettled to Active 
17 Apr    18    active 
18 Apr    30    Active to Minor storm 
COMMENT: IPS Geomagnetic Warning 14 was issued on 12 April and 
is current for interval 13-16 April. Geomagnetic storm activity 
from the X2 event has failed to eventuate. Available data from 
X14 event suggests a shock arrival window of 08-17UT on 18 April. 
Geomagnetic activity may not be strong due to extreme westward 
location of event. Also, there is a 27 day recurrent coronal 
hole pattern suggesting active periods on 18 Apr. 
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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
15 Apr      Normal         Normal         Poor(PCA)
PCA Event : 10Mev Proton/PCA Event Began 15 04 2001 1405UT and is 
	    in progress.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
16 Apr      Normal         Normal         Poor(PCA)
17 Apr      Normal         Normal-Fair    Fair
18 Apr      Fair           Fair           Fair-Poor
COMMENT: High latitude HF communications effected by proton event. 
Polar region comms expected to be degraded today as proton event 
is slowly declining. Further degradation is liekly on 18 Apr 
due to anticipated geomagnetic activity from X14 flare. 
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date   T index
15 Apr   119

Observed Australian Regional MUFs
   Equatorial PNG Region:
     Enhanced by 15% during local day,
     Near predicted monthly values during local night.
  Northern Australian Region:
     Near predicted monthly values during local day,
     Depressed by 15% during local night.
  Southern Australian and New Zealand Region:
     Near predicted monthly values.
  Antarctic Region (Casey/Scott Base):
     Near predicted monthly values over the UT day.


Predicted Monthly T index for April: 120

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
16 Apr   100    Near predicted monthly values 
17 Apr   110    near predicted monthly values 
18 Apr    85    near predicted monthly values/depressed 10 to 
                20% 
COMMENT: IPS HF Communications Warning 24 was issued on 12 April 
and is current for interval 14-16 April. Degraded HF conditions 
expected late on 18 April due to anticipated geomagnetic activity 
from X14 flare. Effects are expected to be confined to mid to 
high latitudes (southern Aus/NZ region). 

IPS Radio and Space Services      | email: asfc at ips.gov.au
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