modelling the ionosphere over europe: investigation of nequick formulation
DESCRIPTION
Modelling the Ionosphere over Europe: Investigation of NeQuick Formulation. Benoît Bidaine 1 - F.R.S.-FNRS - [email protected] Prof. René Warnant 1,2 - [email protected] 1 University of Liège (Unit of Geomatics), Belgium - www.geo.ulg.ac.be - PowerPoint PPT PresentationTRANSCRIPT
Modelling the Ionosphere over Europe:Investigation of NeQuick Formulation
Benoît Bidaine1 - F.R.S.-FNRS - [email protected]. René Warnant1,2 - [email protected]
1University of Liège (Unit of Geomatics), Belgium - www.geo.ulg.ac.be2Royal Meteorological Institute, Belgium - www.meteo.be
November 18th, 20085th European Space Weather Week (Brussels, Belgium)
TEC
Ionosphere
Total Electron Content CET
algorithm NeQuick 1 2
TEC has to be modelled for single frequency receivers.
• GALILEO algorithm usingNeQuick model
First step: let’s investigate NeQuick profile formulation.
• Validate and improve
1. Tools and MethodModelling and measuring the ionosphere
NeQuick 2 improvesTEC estimation over Europe.
NeQuick 2 improvesTEC estimation over Europe.
1. Tools and Method
2. Yearly StatisticsGlobal scheme
Modelling and measuring the ionosphere
NeQuick 2 improvesTEC estimation over Europe.
3. Influence of k UnificationMain modification in NeQuick 2
1. Tools and Method
2. Yearly StatisticsGlobal scheme
Modelling and measuring the ionosphere
NeQuick 2 improvesTEC estimation over Europe.
3. Influence of k UnificationMain modification in NeQuick 2
1. Tools and Method
2. Yearly StatisticsGlobal scheme
Modelling and measuring the ionosphere
4. TEC SplittingDistinguishing bottomside and topside
3. Influence of k Unification
1. Tools and Method
2. Yearly Statistics
4. TEC Splitting
NeQuick is an empirical « profiler ».
• Output = Ne
TEC with integration
• Layer peaks= anchor points
monthly median maps
• NeQuick 2 (Nava et al., 2008)
topside modification
h [km]
Ne [e- m-3]
1. Tools and Method
Bottomside
Topside
ICTP / U Graz / COST 296 and before
We investigate NeQuick formulationusing collocated data.
• Actual measurements instead of monthly median maps constrain by means of ionosonde data manually validated digisonde data
• Modelled vertical TEC vs GPS TEC collocated ionosonde and GPS receiver GIM levelling (Orus et al., 2007)
1TECu 16 cm error for L1
1. Tools and Method
We focus on mid-latitudesand high solar activity.
• Year 2002 (HSA)
• Three European locations with (nearly) collocated digisonde and IGS/EUREF station
1. Tools and Method
3. Influence of k Unification
1. Tools and Method
2. Yearly Statistics
4. TEC Splitting
TEC modelling improveson a yearly basis.
2. Yearly Statistics
0
5
10
15
20
25
30
35
40
El Arenosillo/San Fernando Roquetes Dourbes
TEC
[TEC
u]
Measured NeQuick 1 NeQuick 2
• TEC underestimated on average(! potential bias in GPS TEC data !)
• Bigger (around 20%) underestimation with NeQuick 2
Yearly TEC mean
TEC modelling improveson a yearly basis.
2. Yearly Statistics
Yearly relative TEC standard deviation
0%
5%
10%
15%
20%
25%
30%
El Arenosillo/San Fernando Roquetes Dourbes
TEC
[%]
NeQuick 1 NeQuick 2
• Lower (around 20%) standard deviation with NeQuick 2
3. Influence of k Unification
1. Tools and Method
2. Yearly Statistics
4. TEC Splitting
The topside shape parameter k was unified in NeQuick 2.
3. Influence of k Unification
• k involved in height-dependent scale height
• NeQuick 1: 2 formulas for k (April to September and October to March)
different statistics for each period
• NeQuick 2: 1 formula based on topside soundings
The improvement comes mainly from the topside modification.
• October to March: lower (15%) standard deviation with NeQuick 2
More homogenous with other period
3. Influence of k Unification
-30%
-25%
-20%
-15%
-10%
-5%
0%
5%
10%
El Arenosillo/San Fernando Roquetes Dourbes
Evol
ution
April to September October to March
Evolution of TEC standard deviation from NeQuick 1 to 2
3. Influence of k Unification
1. Tools and Method
2. Yearly Statistics
4. TEC Splitting
The topside plays a major role.
• Integrate bottomside Ne profile from digisonde
bottomside TEC
• Subtract to GPS TEC topside TEC
4. TEC Splitting
0
5
10
15
20
25
30
35
40
El Arenosillo/San Fernando Dourbes
TEC
[TEC
u]
Bottomside Topside
• Big proportion of TEC within topside (3/4, 1/4)
The improvement comes mainly from the topside modification.
• Bias/standard deviation evolution for topside between NeQuick versions corresponding to global statistics
4. TEC Splitting
Yearly topside TEC standard deviation
0
1
2
3
4
5
6
7
8
9
El Arenosillo/San Fernando Dourbes
TEC
[TEC
u]
NeQuick 1 NeQuick 2
NeQuick 2 improves TEC estimation over Europe.
• Benefit from collocated data
• TEC statistics: standard deviation decrease by 20% to reach less than 20% with NeQuick 2 (mid-latitudes stations, high SA)
• Homogenisation thanks to topside modification
• Major role of topside
TEC has to be modelled for single frequency receivers.
• Comparison of different GPS TEC data sets
• Ingestion: use of effective parameters to adapt NeQuick TEC to GPS TEC
• GALILEO Single Frequency Ionospheric Correction Algorithm
Ionosphere
Modelling the Ionosphere over Europe:Investigation of NeQuick Formulation
Benoît Bidaine1 - F.R.S.-FNRS - [email protected]. René Warnant1,2 - [email protected]
1University of Liège (Unit of Geomatics), Belgium - www.geo.ulg.ac.be2Royal Meteorological Institute, Belgium - www.meteo.be
November 18th, 20085th European Space Weather Week (Brussels, Belgium)
We investigate NeQuick formulationusing collocated data.
foF2 yearly difference after validation
0
0,5
1
1,5
2
2,5
El Arenosillo Roquetes Dourbes
Station
foF
2 95
% le
vel [
MH
z]
a
1. Tools and Method
We investigate NeQuick formulationusing collocated data.
1. Tools and Method
sTEC differences averaged by arc (Brussels – 2002)
We investigate NeQuick formulationusing collocated data.
1. Tools and Method
Elevation filter (Brussels – March 28th, 2002)
We investigate NeQuick formulationusing collocated data.
1. Tools and Method
Impact of elevation filter thanks to NeQuick simulations (Brussels – March 28th, 2002)
The topside shape parameter k was unified in NeQuick 2.
3. Influence of k Unification
Monthly TEC mean (Roquetes - 2002)
The topside shape parameter k was unified in NeQuick 2.
3. Influence of k Unification
Monthly TEC standard deviation (Roquetes - 2002)
The improvement comes mainly from the topside modification.
3. Influence of k Unification
Daily TEC profile (El Arenosillo - February 12th, 2002)
The improvement comes mainly from the topside modification.
3. Influence of k Unification
Ne profile (El Arenosillo - February 12th, 2002 – 10 UT)
TEC has to be modelledfor single frequency receivers.
• PhD thesis at ULg – Unit of Geomatics sponsored by FNRS
• Collaborations- RMI (Brussels)- ESA/ESTEC (Noordwijk)- ICTP (Trieste, Italy)- Others to come…
After coffee break
+ posters