REAL TIME AURORA OVAL FORECASTING:
SVALTRACK II
F. Sigernes 1, M. Dyrland 1, P. Brekke 2, E. K. Gjengedal 3, S. Chernouss 4,
D.A. Lorentzen 1, K. Oksavik 1 and C. S. Deehr 5
1
The University Centre in Svalbard (UNIS), N-9171 Longyearbyen, Norway
Space Centre, Oslo, Norway
3 Storm Weather Center, Bergen, Norway
4 Polar Geophysical Institute, Murmansk Region, Apatity, Russia
5 Geophysical Institute, University of Alaska, Fairbanks, USA
2 Norwegian
37th Annual European Meeting on Atmospheric Studies by Optical Methods,
23-27 August 2010, Valladolid, Spain.
A MATEMATICAL REPRESENTATION OF THE AURORAL OVALS
The magnetic input parameter is the AL index – related to the planetary Kp index:
AL  18  12 . 3  K
p
 27 . 2  K
2
p
 2K
3
p
Poleward and equatorward boundaries of auroral oval in geomagnetic co-latitude:
  A0  A1 cos 15  t   1   A2 cos 15 2 t   2   A3 cos 15 3t   3  ,
where amplitudes Ai and phases i is given by
Ai or  i  b 0  b1 log
10
AL  b 2 log
2
10
AL  b 3 log
3
10
AL .
REFERENCES
[1] Starkov, G. V., Mathematical model of the auroral boundaries, Geomagnetism
and Aeronomy, 34, 3, 331-336, 1994.
[2] Starkov, G. V., Statistical dependences between the magnetic activity indices,
Geomagnetism and Aeronomy, 34, 1, 101-103, 1994.
COEFFICIENTS
A0
A1
A2
A3
1
2
3
Poleward boundary of the auroral oval
A0
b0
-0.07
-10.06
-4-44
-3.77
-6.61
6.37
-4.48
b1
24.54
19.83
7.47
7.90
10.17
-1.10
10.16
b2
-12.53
-9.33
-3.01
-4.73
-5.80
0.34
-5.87
b3
2.15
1.24
0.25
0.91
1.19
-0.38
0.98
Equatorward boundary of the auroral oval
b0
1.61
-9.59
-12.07
-6.56
-2.22
-23.98
-20.07
b1
23.21
17.78
17.49
11.44
1.50
42.79
36.67
b2
-10.97
-7.20
-7.96
-6.73
-0.58
-26.96
-24.20
b3
2.03
0.96
1.15
1.31
0.08
5.56
5.11
Equatorward boundary of the diffuse aurora
b0
3.44
-2.41
-0.74
-2.12
-1.68
8.69
8.61
b1
29.77
7.89
3.94
3.24
-2.48
-20.73
-5.34
b2
-16.38
-4.32
-3.09
-1.67
1.58
13.03
-1.36
b3
3.35
0.87
0.72
0.31
-0.28
-2.14
0.76
Table 1. Expansion coefficients for auroral boundaries by Starkov [1].
GEOGRAPHICAL TRANSFORM
Cartesian components:
x m  sin   cos 
  2   t / 24    ( t )
y m  sin   sin 
  (t ) - is the longitudinal difference
between the sub-solar point and
the magnetic poles at time t (hours).
z m  cos 
Geographical coordinates:
 x   cos  0 cos 
  
y  sin  0 cos 
  
 z    sin 
Latitude and longitude:
 sin  0
cos  0
0

cos  0 sin    x m 
  
sin  0 sin   y m
  
  z m 
cos 

 cos
1
(z)
2
  tan
1
( y / x)
 0  82 . 41 N
o
 0   82 . 86 E
o
   / 2   0
 

 
  
x0
x0
VISUALIZATION
Includes:
(1) Equatorward boundary of the diffuse aurora
(2) Aurora oval Kp=3
(3) Magnetic north pole
(4) Field of view aurora observer
(5) Observer location
(6) Moon and Sun information at local site
(7) Position of satellites (Rapideye 1)
The oval is visualized with a stand alone 32bit executable Windows program called
SvalTrackII. The program is written in
Borland’s Delphi – Pascal and uses a
Geographic Information System (GIS) unit
called TGlobe.
The twilight zone, night- and dayside of the
Earth are projected with grades of shade
on the Globe as a function of time.
ANIMATION
Animated aurora
ovals as a function
of Kp index [0…8]
and time for 24th
December 2009
All Sky View
Local all sky view of
ovals as a function of
Kp index [0…8] and
time for 24th
December 2009 from
KHO (78N,16E)
THE +1 HOUR PREDICTED Kp INDEX
SOURCE: Space Weather Prediction Centre (SWPC) at the National Oceanic
and Atmospheric Administration (NOAA).
The Costello Geomagnetic Activity Index
model was developed by Kirt Costello at
Rice University under support from the US
Air Force and Sterling Software, Inc.
It is a neural network algorithm that trains
on the response of the Kp geomagnetic
activity index to solar wind parameters /
data.
The model returns an one hour prediction in
units of Kp. It updates / predicts every 15
minutes.
15 minutes oval update:
http://kho.unis.no
http://www.swpc.noaa.gov/rpc/costello/costello_latest.html
CONCLUDING REMARK
A method to mathematically calculate the size and location
of the aurora oval onto a solar illuminated Earth globe is
presented as function of estimated Kp index and time. The
system may be used as a forecast when the Kp value is
estimated from satellite data one hour upstream in the solar
wind.
PS!
The Svaltrack II program is fredware…it cost II beers.
Acknowledgement
We wish to thank
1. The National Oceanic and Atmospheric Administration
(NOAA) - Space Weather Prediction Centre for allowing us
to download the predicted value of the Kp index every 15
minutes.
2. The Research Council of Norway through the project
named: Norwegian and Russian Upper Atmosphere Cooperation On Svalbard part 2 # 196173/S30 (NORUSCA2).
3. The Nordic Council of Ministers: Arctic cooperation program
# A10162.