[Ips-dsgr] IPS Daily Report - 17 April 03

[rwc]

SUBJ: IPS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 17/2330Z APRIL 2003 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 17 APRIL AND FORECAST FOR 18 APRIL - 20 APRIL
STATUS INDICATORS SOL:GREEN   MAG:** YELLOW **     ION: GREEN
-----------------------------------------------------------
1A. SOLAR SUMMARY
Activity 17 Apr:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 17 Apr: 101/49


1B. SOLAR FORECAST
             18 Apr             19 Apr             20 Apr
Activity     Low                Low                Low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN   100/48             100/48             105/54
COMMENT: Background X-ray flux has increased from previous low 
levels as new active regions rotate onto the visible solar disk. 
A C4 level flare was observed in GOES X-ray imagery after 2200UT. 
The most probable source is an east limb region, so geoeffective 
consequences are unlikely. 



-----------------------------------------------------------
2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 17 Apr: Quiet to Active 

Estimated Indices 17 Apr :  A   K           
   Australian Region      20   3344 4332
      Darwin              20   3344 4332
      Townsville          21   3344 4433
      Learmonth           20   3334 4432
      Canberra            18   3344 3332
      Hobart              21   3345 3332
      Casey(Ant)          21   3444 33--
    
Observed Regional daily pc3 Indices 17 APR : 
      Townsville          36   (Quiet to unsettled)
      Learmonth           76   (Active)
      Canberra           191   (Severe storm)
      Hobart              NA
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 17 Apr : A 
           Fredericksburg        29
           Planetary             33                         

Observed AFr/Ap Indices 16 Apr :  A   K
           Fredericksburg        13
           Planetary             31   4346 3354     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
18 Apr    18    active 
19 Apr    15    Unsettled to Active 
20 Apr    12    Unsettled 
COMMENT: Solar wind speed remained elevated at over 700 km/s 
for the first half of the UT day. A slow decline in speed occurred 
over the second half of the day as the coronal hole rotates out 
of geoeffective range. The interplanetary magnetic field sustained 
a southward polarity for much of the middle part of the UT day. 
Active conditions were observed at low to mid latitudes during 
this period on the IPS magnetometer network, with isolated minor 
storm periods at high latitudes. Geomagnetic conditions should 
decline from active to unsettled over the next two days. 

-----------------------------------------------------------
3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
17 Apr      Normal-fair    Normal         Normal-fair    
PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
18 Apr      Normal         Normal-Fair    Fair
19 Apr      Normal         Normal         Normal-Fair
20 Apr      Normal         Normal         Normal-Fair
COMMENT: Brief isolated depressions observed overnight at low 
latitudes. Variable periods of absorption and disturbance observed 
throughout the UT day at high latitudes in association with elevated 
geomagnetic activity. 
-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
17 Apr    83

Observed Australian Regional MUFs
   Equatorial PNG Region:
      Enhanced by 15% during local day,
      Enhanced by 25% during local night, with 
      variable local depressions.
   Northern Australian Region:
      Near predicted monthly values.
   Southern Australian and New Zealand Region:
      Near predicted monthly values.
   Antarctic Region (Casey/Scott Base):
      Slightly below predicted monthly values
      with variable extended local disturbances.


Predicted Monthly T index for April:  77

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
18 Apr    90    near predicted monthly values 
19 Apr    90    Near predicted monthly values 
20 Apr   105    5 to 10% above predicted monthly values 
COMMENT: Brief ionospheric depressions observed again overnight 
at low latitudes. Extensive spread-F conditions observed Antarctic 
regions. Periods of spread-F and high absorption observed at 
high latitudes in response to coronal hole induced geomagnetic 
disturbance. Mild ionospheric depressions observed after local 
dawn today NZ/S Ocean regions. Degraded HF conditions may be 
experienced today S Aus/NZ/Antarctic regions. Current solar coronal 
hole induced conditions should improve over the next two days. 
-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 16 Apr
       Daily Proton Fluence >1 MeV:   6.6E+06
       Daily Proton Fluence >10 MeV:  1.0E+04
       Daily Electron Fluence >2 MeV: 1.00E+08 (normal)
       X-ray background: B1.2
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.

ACE Satellite Solar Wind Day Averaged Data for 16 Apr
Speed: 723 km/sec  Density:    2.4 p/cc  Temp:   316000 K  Bz:   0 nT

(Courtesy Space Environment Center, Boulder USA)
ACE data can be incorrect during strong proton events.
-----------------------------------------------------------


IPS Radio and Space Services      | email: asfc at ips.gov.au
PO Box 1386                       | WWW: http://www.ips.gov.au
Haymarket NSW 1240  AUSTRALIA     | FTP: ftp://ftp.ips.gov.au 
tel: +61 2 9213 8010              | fax: +61 2 9213 8060