behavior of the total electron content over three stations of the lisn zone m. mosert 1, m. gende...
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Behavior of the total electron content over three stations of
the LISN zoneM. Mosert1, M. Gende 2 ,C. Brunini2, R.Ezquer3,4
1 Instituto de Ciencias Astronómicas, de la Tierra y del Espacio (ICATE)-CONICET- UNSJ, Avda. España 1512 (Sur), 5400 San Juan, Argentina, [E-mail: [email protected]]
2Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata- CONICET, La Plata, Argentina
3CIASuR, Facultad Regional Tucumán, Universidad Tecnológica Nacional, Tucumán, Argentina.
4 Laboratorio de Ionósfera, Dpto. de Física, FACET, UNT- CONICET, Tucumán, Argentina
LISN 2 Workshop 7-11 November, 2011, Sao Jose Dos Campos, Brazil
In this talk
We analyze the behavior of total electron contentusing data from Jicamarca (-12.0°S; 283°E); Tucuman (-26.9°S; 294.6°E) and El Leoncito, SanJuan (-31.5°S; 290.4°E). The database includes TEC measurements obtained from Digisondeobservations (ITEC) and GPS signals (GPSTEC). The day to day variability is analyzed.
Comparisonsbetween observations and the IRI –2007predictions are also done.
Data Used
Station Lat. Long. Years Rz12
Jicamarca -12.0° S 283° E 2001-2008 HSA-LSA
Tucuman -26.9°S 294.6°E 2008 LSA El Leoncito -31.5°S 290.4°E 2008 LSA
Representative months: January (summer), April (fall), July (winter) andOctober (spring)
Universal Time: 00 to 23
Data Used
ITEC: (h= 1000 km) obtained from digisonde ionograms using the true height inversion program NHPC (Reinisch and Huang, 1983; Huang and Reinisch, 1996)
GPSTEC: Vertical TEC derived from oblique GPS signals using La Plata Ionospheric Model, LPIM (Brunini et al, 2001)
IRITEC: (h =1000 km) obtained from IRI-2007 version (3 Topside options: IRI-2001, IRI-2001
corrected and NeQuick).
Our analysis
1. Behavior of GPSTEC over Jicamarca , Tucumán and El Leoncito, San Juan
2. Behavior of ITEC over Jicamarca
3. Analysis of topside electron density profiles
1. Behavior of GPSTEC over Jicamarca, Leoncito and Tucuman
Seasonal Variations – 2008 (Rz12= 2.8)
Fig. 1
0 2 4 6 8 10 12 14 16 18 20 220
5
10
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25
30
35
40 El Leoncito (San J uan)
GP
ST
EC
[TE
CU
]
UT0 2 4 6 8 10 12 14 16 18 20 22
0
5
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40J icamarca
GP
ST
EC
[TE
CU
]
UT
0 2 4 6 8 10 12 14 16 18 20 220
10
20
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50Tucumán
GP
ST
EC
[TE
CU
]
UT
Summer Equinox Winter
Latitudinal Variations – GPSTEC - 2008 (Rz12= 2.8)
Fig. 2
0 2 4 6 8 10 12 14 16 18 20 220
5
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35
40 January
GP
ST
EC
[TE
CU
]
UT0 2 4 6 8 10 12 14 16 18 20 22
0
5
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40 April
GP
ST
EC
[TE
CU
]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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40 July
GP
ST
EC
[TE
CU
]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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40 October
GP
ST
EC
[TE
CU
]
UT
Jica Leon Tuc
2. Behavior of ITEC over Jicamarca
Seasonal Variations
Solar Activity Variations
Day to Day Variability
Comparisons between observations and IRI predictions
0 2 4 6 8 10 12 14 16 18 20 220
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40
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100 January
ITE
C[T
EC
U]
UT0 2 4 6 8 10 12 14 16 18 20 22
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100April
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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100July
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C[T
EC
U]
UT0 2 4 6 8 10 12 14 16 18 20 22
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100 October
ITE
C[T
EC
U]
UT
Median Mean
ITEC – Median or Mean values? Jicamarca 2002 (Rz12= 102)
F
Fig. 3
Jicamarca 2006 (Rz12=16)
0 2 4 6 8 10 12 14 16 18 20 220
10
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50 JanuaryIT
EC
[TE
CU
]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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60 April
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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50 July
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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50October
ITE
C[T
EC
U]
UT
Median Mean
Fig. 4
-2 0 2 4 6 8 10 12 14 16 18 20 22 24
0
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80
100ITEC - April 2002
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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80
100ITEC - January 2002
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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100ITEC - July 2002
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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80
100ITEC - October 2002
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
Fig 5 .Jicamarca- Medians and Quartiles- 2002 (HSA)
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - January 2006
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 22
0
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60ITEC - April 2006
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - July 2006
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - October 2006
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
Fig 6. Jicamarca- Medians and Quartiles- 2006 (LSA)
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - January 2007
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - April 2007
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - July 2007
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
0 2 4 6 8 10 12 14 16 18 20 220
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50ITEC - October 2007
ITE
C[T
EC
U]
UT
ITECMed Qup Qlo
Fig. 7 . Jicamarca- Medians and Quartiles- 2007 (LSA)
0 2 4 6 8 10 12 14 16 18 20 220
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100 2006 (LSA)
ITE
C[T
EC
U]
UT
Fig. 8
0 2 4 6 8 10 12 14 16 18 20 220
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1002002 (HSA)
ITE
C[T
EC
U]
UT
Jan April July Octu
Jicamarca ITECSeasonal Variations 2006 (Rz12= 16) – 2002 (Rz12= 102)
0 2 4 6 8 10 12 14 16 18 20 220
10
20
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50ITEC - Jicamarca 2007 (LSA)
ITE
C[T
EC
U]
UT
Jan April July Octu
Fig. 9.
Fig. 10
0 2 4 6 8 10 12 14 16 18 20 220
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100July
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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100 January IT
EC
[TE
CU
]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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100 April
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 220
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100 October
ITE
C[T
EC
U]
UT
2006 2002
Jicamarca ITEC – Solar Activity Variations
Day to Day Variability
Variability indexes
Standard Deviations (SD)V%: Standard Deviations % = (SD/mean) * 100
Upper and lower quartilesCup= upper quartile/median Cup >1Clo= lower quartile/median Clo <1
Variability index: Cup-Clo
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
2,5
3,0
3,5
January
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
2,5
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July
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
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3,0
3,5 Abril
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
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2,0
2,5
3,0
3,5 Octubre
Ind
exe
s C
up
an
d C
lo
UT
Clo Cup
Fig. 11
Jicamarca - ITEC – 2006 (LSA: Rz12= 16)Variability indexes Cup and Clo
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
2,5
3,0
3,5 January
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
2,5
3,0
3,5 July
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
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2,0
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3,0
3,5 April
Ind
exe
s C
up
an
d C
lo
UT
0 2 4 6 8 10 12 14 16 18 20 220,5
1,0
1,5
2,0
2,5
3,0
3,5 October
Ind
exe
s C
up
an
d C
lo
UT
Clo Cup
Jicamarca - ITEC – 2002 (HSA: Rz12= 102)Variability indexes Cup and Clo
Fig. 12
Fig. 13
Jicamarca – ITEC – 2002 (HSA) / 2006(LSA)Variability index V%
0 2 4 6 8 10 12 14 16 18 20 220
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220January
V%
UT
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V%
UT
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V%
UT0 2 4 6 8 10 12 14 16 18 20 22
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220 October
V%
UT
2002 2006
Comparisons between ITEC and IRITEC predictions
Fig. 14
Jicamarca - IRITEC predictions 2006 Rz= 16
0 2 4 6 8 10 12 14 16 18 20 220
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40 January
ITE
C[T
EC
U]
UT0 2 4 6 8 10 12 14 16 18 20 22
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ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 22-10
-5
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ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 22-10
-5
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40October
ITE
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EC
U]
UT
ITEC IRI-NeQ IRI-2001 IRI-2001corr
0 2 4 6 8 10 12 14 16 18 20 22
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100April
ITE
C[T
EC
U]
UT
0 2 4 6 8 10 12 14 16 18 20 22
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ITE
C[T
EC
U]
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Jicamarca 2002 – ITEC / IRITEC
Fig. 15
0 2 4 6 8 10 12 14 16 18 20 220
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100January
ITE
C[T
EC
U]
UT
3. Topside Electron Density Profiles
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UT 13.59
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h[k
m]
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UT 14.29
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m]
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UT 17.17
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m]
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UT 18.02
Nx105[cm-3]
h[k
m]
IRI01C IRINQ IRI01 ISR
Fig. 16
Jicamarca 13/11/2001 (Rz12= 111)
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m]
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m]
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UT 16.00
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h[k
m]
IRI01C IRINQ IRI01 ISR
Fig. 17
Jicamarca 11/06/2002 (Rz12= 102)
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UT 05.49
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m]
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UT 11.35
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h[k
m]
IRI01C IRINQ IRI01 ISR
Fig. 18
Jicamarca 15/04/2004 (Rz12= 42)
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UT 20.00
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m]
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UT 22.42
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m]
IRI01C IRINQ IRI01 ISR
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UT 23.13
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h[k
m]
Fig. 19
Jicamarca 28/06/2006 (Rz12= 16)
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UT 16.29
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IRI01C IRINQ IRI01 ISR
Fig. 20
Jicamarca 30/06/2006 (Rz12= 16)
Summary
A study of the behavior of the total electron content (TEC) has been done using measurements obtained at Jicamarca, Perú (12.0 S; 283.0 E) and at Tucumán (26.9 S; 294.6 E ) and El Leoncito, San Juan (31.5 S; 294.6 E ), Argentina. The database includes TEC data derived from ground-based ionosonde data (ITEC) and from GPS satellite signals (GPSTEC). The diurnal, seasonal, solar activity variations and the day to day variability have been analyzed. Comparisons with the predictions of the last version of the International Reference Ionosphere model (IRI-2007) are also done.
The results show that the total electron content increases gradually from hours of minimum TEC (05-06 LT) in all the seasons reaching maximum values around midday. At sunset the TEC values begin to decrease reaching minimum values around sunrise. The TEC measurements generally show lower values in winter than in summer. The winter-summer differences are not so evident in the year of low solar activity. The largest daytime peak values are observed in the two equinoctial months.The IRI predictions generally overestimate the total electron content during nighttime and underestimate during daytime.Taking into account that the most contribution of TEC comes from the topside electron density profile, these results suggest that the discrepancies between IRI predictions and TEC measurements are due to the shape of the topside profile assumed by the model. In general NeQuick topside option follows better the ISR data.
Final Comments
Taking into account these results additional efforts are being done in order:
(a)To improve the modeling of the electron density profile.
(b) To advance in the formulation of a day to day variability model.
and some comments about the new ionosone installed at Tucuman.
B. San Martin
B. Belgrano(IAA)
Tucumán 2(CIASUR-FRT and UTN)
La Plata(GESA-UNLP)
Operative ionospheric stations
Tucumán (-26.9º S , 294.6º E) is placed near the Southern crest of the equatorial anomaly.
Since 1957 to 1987 ionospheric measurements were obtained with the analogue ionosonde of the Ionospheric Station of National University of Tucumán (UNT).
In 2007, within the Italian-Argentine collaboration supported by the Istituto Italo Latino Americano (IILA), an Advanced Ionospheric Sounder (AIS) built at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, was installed at the Upper Atmosphere and Radiopropagation Research Center (Centro de Investigación de Atmósfera Superior y Radiopropagación – CIASUR) of the Tucumán Regional Faculty of the National Technological University (UTN). That ionosonde is equipped with Autoscala, software able to perform an automatic scaling of the ionograms.
Figure 1 shows AIS, the antenna and an ionogram obtained at CIASUR.
Fig. 1. AIS, the antenna and an ionogram obtained at CIASUR
SF and ScintillationsSF and Scintillations
Tucuman received power from PRN 02 Noche del 07/11/07
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25 25,5 26 26,5 27 27,5 28 28,5 29 29,5 30
UT
Rcv
d P
wr
(dB
)
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1:45 UT
Satélite 2
22:45 LT
Tucuman Recived Power from PRN 23Noche del 16/Abril/2008
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Satélite 230:45 LT
Tucuman Received Power from PRN 19Noche del 16/Abril/2008
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r (d
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Satélite 13
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First results
The data recorded by the AIS-INGV/Autoscala system installed at CIASUR showed ionograms with possible additional stratifications, different to E, F1 and F2 layers (Pezzopane et al 2007).
Fig. 2 shows an example were a F1.5 additionalstratification is observed.
Fig. 2. Ionograms recorded on 23 September 2007 from 14:05 to 14:45 UT by the AIS-INGV ionosonde installed at Tucumán, and autoscaled by Autoscala. The development and decay of a F1.5 additional stratification are highlighted using open circles. (From Pezzopane et al 2007)
First results
Range spread-F (RSF) and occurrence of “satellite” traces prior to RSF onset were also studied with AIS measurements.(Cabrera et al., 2010).
Fig. 3 shows a case where ST and RSF are observed.
Fig. 3. Sequence of ionograms recorded on 4 September 2007 showing (a) diffuse trace in the second order mode, (b) ST appearance adjacent to the low- frequency end of the first order mode, (c) RSF commencement, and (d) RSF fully developed. (From Cabrera et al, 2010)
Acknowledgments
We gratefully acknowledge to FAPESP for the financial support and to INPE for hosting this event in particular to Eurico di Paula.
The authors wish to thank to the staff of the JRO for the use of ISR data.
Obrigado!!