[Ips-dsgr] SWS Daily Report - 20 April 20 issued 2334 UT on 20 Apr 2020

rwc rwc at ips.gov.au
Tue Apr 21 09:34:18 EST 2020


SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/20 APRIL 2020 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 20 APRIL AND FORECAST FOR 21 APRIL - 23 APRIL
STATUS INDICATORS SOL:GREEN   MAG:GREEN     ION: GREEN
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1A. SOLAR SUMMARY
Activity 20 Apr:  Very low

Flares: none.

Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr:  68/2


1B. SOLAR FORECAST
             21 Apr             22 Apr             23 Apr
Activity     Very low           Very low           Very low
Fadeouts     None expected      None expected      None expected
10.7cm/SSN    69/3               69/3               69/3

COMMENT: Solar activity was very low on UT day, 20 April. Very 
low levels of solar activity are expected for the next three 
UT days, 21-23 April. The visible disc has been spotless and 
there are no returning regions expected. No Earth bound CMEs 
observed in available LASCO and STEREO images. The day started 
with the solar wind parameters at nominal levels, but a weak 
shock was observed in the solar wind at 0130UT. Post shock, the 
solar wind suddenly increased from 295 km/s to 330 km/s and reached 
a peak of 388 km/s at 0826 UT. During the later hours of the 
day the solar wind speed gradually decreased to around 330 km/s 
by 2300 UT. The total IMF (Bt) was initially between 3 nT and 
6 nT. Post shock, Bt increased up to around 16 nT. The north-south 
IMF component (Bz) ranged from -5 nT to +7 nT until around 0630 
UT, then went negative up to -15 nT and stayed negative until 
1330 UT. Bz then turned positive and rose up to +13 nT. The solar 
wind particle density was around 3 ppcc before the shock and 
postshock it increased to 10 ppcc and rose up to around 35 ppcc. 
After 0730 UT, the particle density varied between 6 and 14 ppcc. 
The shock may have arrived because of the unexpected glancing blow of a 
slow CME that was observed on UT day 15 April. Solar wind parameters 
may show minor to moderate strengthening on UT day 21 April and 
minor strengthening on 22 and 23 April.

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2A. MAGNETIC SUMMARY

Geomagnetic field for Australian Region 20 Apr: Quiet to Minor 
Storm

Estimated Indices 20 Apr : A   K           
   Australian Region      13   22335300
      Darwin              13   33334301
      Townsville          15   33335301
      Learmonth           14   32335300
      Alice Springs       13   22335301
      Gingin              13   22335300
      Canberra             9   22334200
      Hobart              14   22345300    

Estimated Antarctic Regional K Indices 20 Apr :
      Macquarie Island    36   21567300
      Casey               14   34333312
      Mawson              16   24433323

Observed Regional daily pc3 Indices 20 Apr : 
      Darwin               0   (Quiet)
      Townsville           0   (Quiet)
      Learmonth            2   (Quiet)
      Alice Springs        0   (Quiet)
      Gingin               2   (Quiet)
      Canberra             4   (Quiet)
      Melbourne           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 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 Apr : A 
           Fredericksburg        15
           Planetary             20                         

Observed AFr/Ap Indices 19 Apr :  A   K
           Fredericksburg         2
           Planetary              5   1001 2322     


2B. MAGNETIC FORECAST 
Date      Ap    Conditions
21 Apr    12    Mostly unsettled, isolated active periods possible
22 Apr    10    Quiet to Unsettled
23 Apr    10    Quiet to Unsettled

COMMENT: SWS Geomagnetic Warning 2 was issued on 20 April and 
is current for 20-21 Apr. In the SWS magnetometer data for 20 
Apr, a weak (10nT) impulse was observed at 0232UT. On UT day 
20 April, the geomagnetic conditions in the Australian and Antarctic 
regions varied from quiet to minor storm levels. Short periods 
of isolated major storm were also recorded in the Antarctic region. 
Global geomagnetic conditions may vary from unsettled to active 
levels on UT day 21 April and quiet to unsettled levels on 22 
and 23 April.

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3A. GLOBAL HF PROPAGATION SUMMARY
	            Latitude Band
Date        Low            Middle         High 
20 Apr      Normal         Normal         Normal         

PCA Event : No event.

3B. GLOBAL HF PROPAGATION FORECAST
	            Latitude Band
Date        Low            Middle         High 
21 Apr      Normal         Normal         Normal-fair
22 Apr      Normal         Normal         Normal
23 Apr      Normal         Normal         Normal

COMMENT: Maximum usable frequencies (MUFs) were near predicted 
monthly values with periods of minor to significant enhancements 
on UT day, 20 Apr. Nearly similar HF conditions may be expected 
on UT days 22 and 23 April. However, minor MUF depressions may 
be observed on UT day 21 April.

-----------------------------------------------------------
4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY


Date   T index
20 Apr     1

Observed Australian Regional MUFs
   Cocos Island Region:
      Enhanced by 25% during local day.
      Enhanced by 105% during local night.
   Niue Island Region:
      No data available during local day.
      No data available during local night.
      Enhanced by 45% after local dawn.
   Northern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 45% during local night.
      Enhanced by 35% after local dawn.
   Southern Australian Region:
      Near predicted monthly values during local day.
      Enhanced by 25% during local night.
      Enhanced by 20% after local dawn.
   Antarctic Region (Casey/Scott Base/Davis/Mawson):
      Near predicted monthly values over the UT day.

Monthly T index:
Month  T index
Mar      1
Apr      -14
May      -14

4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date   T index  MUFs
21 Apr    -5    Near predicted monthly values/depressed 10 to 
                20%
22 Apr     0    Near predicted monthly values
23 Apr     0    Near predicted monthly values

COMMENT: Maximum usable frequencies (MUFs) were near predicted 
monthly values with periods of minor to significant enhancements 
for the Australian region on UT day, 20 Apr. Nearly similar HF 
conditions may be expected on UT days 22 and 23 April. However, 
minor MUF depressions may be observed on UT day 21 April.

-----------------------------------------------------------
5. SPACE ENVIRONMENT SUMMARY

GOES satellite data for 19 Apr
       Daily Proton Fluence >1 MeV:   6.2E+04
       Daily Proton Fluence >10 MeV:  4.7E+04
       Daily Electron Fluence >2 MeV: 1.70E+06   (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 1%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
       X-ray background: <A1.0

DSCOVR Satellite Solar Wind Day Averaged Data for 19 Apr
Speed: 317 km/sec  Density:    3.0 p/cc  Temp:    16700 K  Bz:   0 nT

(Courtesy Space Weather Prediction Center, Boulder USA)
-----------------------------------------------------------

Space Weather Services              email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386                         WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240  AUSTRALIA       FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010                fax: +61 2 9213 8060 

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