real time reconstruction of 3-d electron density distribution over europe with tad profiler ivan...
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Real time reconstruction of 3-D electron density distribution
over Europe with TaD profiler
Ivan Kutiev1,2, Pencho Marinov1, Anna Belehaki2
1Bulgarian Academy of Sciences2National Observatory of Athens
The core Topside Sounder Model (TSM)and TSM profiler (TSMP)
TSM (Topside Sounder Model) provids
- topside scale height HT, - upper (O+-H+) transition height hT, - (scale height)/(transition height)
ratio RT
TSMP (Topside Sounder Model Profiler) provides the shape of the vertical electron density (Ne) profile in topside ionosphere and plasmasphere as a sum of O+ and H+ individual profiles. When the density and height of the F layer peak are specified, TSMP defines the Ne profile.
Hp
HT
TSMP-assisted Digisonde profiler (TaD)
In the topside: TSMP provides the shape of Ne profile At F layer peak: Digisonde provides NmF2, and hmF2 The new coupled profiler is named TSMP-assisted Digisonde
(TaD) profiler. TaD now provides electron density profiles in topside ionosphere and plasmasphere at the time of Digisonde sounding, e.g. in real time.
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7electron density cm -3
0
1000
2000
3000
4000
altit
ude,
km
Digisonde
Ebro 5 June 200107:00
O +
a - C h a p m a ns c a l e h e i g h t = 2 H m
H +
h T
Digisonde and TaD topside profiles
Digisonde topside profile is expressed by the α-Chapman formula. At higher altitudes the profile decreases with a scale height 2Hm (Hm is the neutral scale height).
The O+ scale height HT, provided by TaD is approximately 1.25 times larger than Hm.
Further improvement of TaD• Modeling the He+ profile around transition height hT
• Modeling the Hp/HT ratio as a function of geomagnetic latitude, month, local time, and O+ density at transition height hT (using ISIS-1 topside sounder Ne profiles)
• Profile parameters Hp and hT are presented by their ratios with HT, so the shape of the whole TaD profile is made dependent on HT only.
• Adjustment of the integral of TaD profile with measured GNSS-TEC.
Using TaD profiler in reconstruction of 3-D electron density distribution (EDD) over Europe
Concept: • Produce TaD Ne profiles over the Digisonde stations of the DIAS
ionosonde network, adjusted by TEC values extracted from the ROB GNSS-TEC maps.
• For the same mapping area calculate the profile parameters: NmF2, hmF2, HT, hT, and Hp at all grid nodes (1˚x1˚) by using the Polyweight spatial interpolation procedure.
• Produce TaD profiles at grid nodes.
• Develop a procedure calculating electron density at any point of the 3-D space by interpolating between the proper profile values at grid nodes.
DIAS ionosonde network
European DIAS (Digital Upper Atmosphere Server) network consists of 8 Digisonde stations. They provide foF2, hmF2, and bottomside Ne profile every 15 min.
(http://dias.space.noa.gr)
Mapping area is confined to (-10˚,25˚)E and (35˚,60˚)N to comply with the GNSS-TEC maps provided by Royal Observatory of Belgium (ROB)
-10 -5 0 5 10 15 20 25
longitude
35
40
45
50
55
60
latit
ude
E A
E B
C HD B
J R
P Q
R O
A T
Maps of TaD profile parameters
Maps are produced by Polyweight interpolation procedure, after the TaD profiles were calculated and adjusted with GNSS-TEC values at each grid node (1˚x1˚) geographic coordinates.
foF2
-10 -5 0 5 10 15 20 25
longitude
l a t i t
u d e
8
8.1
8.2
8.3
8.4
8.5
8.6
TEC
24.4
25.2
26
26.8
27.6
28.4
29.2
30
252
256
260
264
268
272
276
hm F2
hT
H T
H p
-10 -5 0 5 10 15 20 25
longitude
650
750
850
950
1050
1150
100
110
120
130
140
150
160
800
900
1000
1100
1200
1300
1400
1500
08 M arch 2012, 13:45 U T
Electron density maps at fixed altitudes
Ne distribution at fixed heights is produced by using TaD profiles at the grid nodes. Ne profiles below hmF2 are provided by Digisonde software. Level ranges are different for the different heights.
Vertical slices from the 3-D EDD
Vertical Ne profiles at -10˚E, 35˚N
b
g
a
cde f
h
-10 -5 0 5 10 15 20 25long itude
200
400
600
800
1000
altitu
de
acge
0
3E+005
5E+005
8E+005
1E+006
-10 -5 0 5 10 15 20 25
long itude
35
40
45
50
55
60
latitu
de
1000 km
1.3E+004
1.8E+004
2.3E+004
2.8E+004
Vertical Ne profiles at 25˚E, 60˚N
b
g
a
cde f
h
-10 -5 0 5 10 15 20 25long itude
200
400
600
800
1000
altitu
de
acge
-10 -5 0 5 10 15 20 25
longitude
35
40
45
50
55
60
latitud
e
1000 km
Ne profile along the raypath (-10˚,35˚) and (25˚,60˚)
b
g
a
cde f
h
-10 -5 0 5 10 15 20 25longitude
200
400
600
800
1000
altitu
de
acge
-10 -5 0 5 10 15 20 25
longitude
35
40
45
50
55
60
latitud
e
1000 km
Ne profile along the raypath (25˚,35˚) and (-10˚,60˚)
b
g
a
cde f
h
-10 -5 0 5 10 15 20 25longitude
200
400
600
800
1000
altitu
de
acge
-10 -5 0 5 10 15 20 25
longitude
35
40
45
50
55
60
latitud
e
1000 km
Conclusion
• On the basis of TaD profiling technique, a new method is developed for reconstruction of the 3-D electron density distribution (EDD) over Europe in real time.
• Respective software allows obtaining the EDD along arbitrary raypaths within the mapping area.
• The software is planned to be implemented in DIAS system and consequently to be used to upgrade the products streaming from DIAS to the ESA Space Situational Awareness Space Weather Services.
Thank you
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