Behavior of the total electron
content over three stations of the
LISN zone
M. 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: mmosert@icate-conicet.gob.ar]
2Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La PlataCONICET, 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 content
using data from Jicamarca (-12.0°S; 283°E);
Tucuman (-26.9°S; 294.6°E) and El Leoncito, San
Juan (-31.5°S; 290.4°E). The database includes
TEC measurements obtained from Digisonde
observations (ITEC) and GPS signals (GPSTEC).
The day to day variability is analyzed. Comparisons
between observations and the IRI –2007
predictions are also done.
Data Used
Station
Lat.
Long.
Years
Jicamarca
-12.0° S
283° E
Tucuman
-26.9°S
294.6°E 2008
El Leoncito
-31.5°S
Rz12
2001-2008 HSA-LSA
290.4°E 2008
LSA
LSA
Representative months: January (summer), April (fall), July (winter) and
October (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)
Jicamarca
40
El Leoncito (San Juan)
40
35
35
30
GPSTEC[TECU]
25
20
15
25
20
15
10
10
5
5
0
0
0
0
2
4
6
8
10
12
14
16
18
20
2
22
Tucumán
50
Summer
Equinox
Winter
40
30
20
10
0
0
2
4
6
8
10
4
6
8
10
12
UT
UT
GPSTEC[TECU]
GPSTEC[TECU]
30
12
UT
Fig. 1
14
16
18
20
22
14
16
18
20
22
Latitudinal Variations – GPSTEC - 2008 (Rz12= 2.8)
January
35
35
30
30
25
20
15
10
25
20
15
10
5
5
0
0
2
4
6
8
10
12
14
16
18
20
0
22
0
UT
2
4
6
8
10
12
14
16
18
20
22
UT
July
40
October
40
35
35
30
30
GPSTEC[TECU]
GPSTEC[TECU]
April
40
GPSTEC[TECU]
GPSTEC[TECU]
40
25
20
15
25
20
15
10
10
5
5
0
Jica
Leon
Tuc
0
0
2
4
6
8
10
12
14
16
18
20
22
UT
0
2
4
6
8
10
12
UT
Fig. 2
14
16
18
20
22
2. Behavior of ITEC over Jicamarca
Seasonal Variations
Solar Activity Variations
Day to Day Variability
Comparisons between observations and IRI
predictions
ITEC – Median or Mean values?
Jicamarca 2002 (Rz12= 102)
January
100
80
80
60
ITEC[TECU]
ITEC[TECU]
April
100
40
20
60
40
20
0
0
2
4
6
8
10
12
14
16
18
20
0
22
0
UT
6
8
10
12
14
16
18
80
80
60
60
40
20
0
2
4
6
8
10
12
UT
22
40
Median
Mean
20
0
20
October
100
ITEC[TECU]
ITEC[TECU]
4
UT
July
100
2
14
16
18
20
22
0
0
2
4
6
8
10
12
14
16
18
20
22
UT
Fig. 3
Jicamarca 2006 (Rz12=16)
January
50
April
60
50
40
ITEC[TECU]
ITEC[TECU]
40
30
20
30
20
10
10
0
0
0
2
4
6
8
10
12
14
16
18
20
22
0
2
4
6
8
10
UT
July
50
14
16
18
20
22
October
50
40
ITEC[TECU]
40
ITEC[TECU]
12
UT
30
20
30
20
10
10
Median
Mean
0
0
0
2
4
6
8
10
12
UT
14
16
18
20
22
0
2
4
6
8
10
12
14
16
18
20
22
UT
Fig. 4
ITEC - April 2002
ITEC - January 2002
100
100
80
80
ITEC[TECU]
ITEC[TECU]
60
60
40
40
20
20
ITECMed
Qup
Qlo
0
0
2
4
6
8
10
12
14
16
18
20
ITECMed
Qup
Qlo
0
-2
22
0
2
4
6
8
10
12
14
16
18
20
22
24
UT
UT
ITEC - July 2002
ITEC - October 2002
100
100
80
ITEC[TECU]
ITEC[TECU]
80
60
40
60
40
20
20
ITECMed
Qup
Qlo
ITECMed
Qup
Qlo
0
0
0
0
2
4
6
8
10
12
14
16
18
20
22
2
4
6
8
10
12
14
16
18
20
22
UT
UT
Fig 5 .Jicamarca- Medians and Quartiles- 2002 (HSA)
ITEC - January 2006
50
ITEC - April 2006
60
50
40
ITEC[TECU]
ITEC[TECU]
40
30
20
10
30
20
10
ITECMed
Qup
Qlo
ITECMed
Qup
Qlo
0
0
0
2
4
6
8
10
12
14
16
18
20
22
0
2
4
6
8
10
UT
ITEC - July 2006
50
12
14
16
18
20
22
UT
40
ITEC - October 2006
50
ITECMed
Qup
Qlo
30
ITEC[TECU]
ITEC[TECU]
40
20
30
20
10
10
ITECMed
Qup
Qlo
0
0
2
4
6
8
10
12
UT
14
16
18
20
22
0
0
2
4
6
8
10
12
14
16
18
UT
Fig 6. Jicamarca- Medians and Quartiles- 2006 (LSA)
20
22
ITEC - April 2007
ITEC - January 2007
50
50
40
ITEC[TECU]
ITEC[TECU]
40
30
20
30
20
10
10
ITECMed
Qup
Qlo
0
0
0
2
4
6
8
10
12
14
16
18
20
ITECMed
Qup
Qlo
0
22
2
4
6
8
10
UT
ITEC - July 2007
14
16
18
20
22
ITEC - October 2007
50
50
40
ITECMed
Qup
Qlo
30
20
10
ITEC[TECU]
40
ITEC[TECU]
12
UT
30
20
10
0
ITECMed
Qup
Qlo
0
0
2
4
6
8
10
12
UT
14
16
18
20
22
0
2
4
6
8
10
12
14
16
18
20
22
UT
Fig. 7 . Jicamarca- Medians and Quartiles- 2007 (LSA)
Jicamarca ITEC
Seasonal Variations 2006 (Rz12= 16) – 2002 (Rz12= 102)
2006 (LSA)
2002 (HSA)
100
90
90
80
80
70
70
60
60
ITEC[TECU]
ITEC[TECU]
100
50
40
30
50
40
30
20
Jan
April
July
Octu
20
10
10
0
0
2
4
6
8
10
12
14
16
18
20
22
0
0
UT
2
4
6
8
10
12
UT
Fig. 8
14
16
18
20
22
ITEC - Jicamarca 2007 (LSA)
50
Jan
April
July
Octu
ITEC[TECU]
40
30
20
10
0
0
2
4
6
8
10
12
14
UT
Fig. 9.
16
18
20
22
Jicamarca ITEC – Solar Activity Variations
January
100
80
ITEC[TECU]
80
ITEC[TECU]
April
100
60
40
60
40
20
20
0
0
0
2
4
6
8
10
12
14
16
18
20
0
22
2
4
6
8
10
UT
July
14
16
18
20
22
October
100
80
80
60
60
ITEC[TECU]
ITEC[TECU]
100
12
UT
40
20
2006
2002
40
20
0
0
2
4
6
8
10
12
14
16
18
20
0
22
0
UT
2
4
6
8
10
12
UT
Fig. 10
14
16
18
20
22
Day to Day Variability
Variability indexes
Standard Deviations (SD)
V%: Standard Deviations % = (SD/mean) * 100
Upper and lower quartiles
Cup= upper quartile/median Cup >1
Clo= lower quartile/median Clo <1
Variability index: Cup-Clo
Jicamarca - ITEC – 2006 (LSA: Rz12= 16)
Variability indexes Cup and Clo
3,5
3,5
Abril
January
3,0
Indexes Cup and Clo
Indexes Cup and Clo
3,0
2,5
2,0
1,5
2,5
2,0
1,5
1,0
1,0
0,5
0
0,5
0
2
4
6
8
10
12
14
16
18
20
2
4
6
8
10
22
12
14
16
18
20
22
UT
UT
3,5
3,5
July
3,0
Indexes Cup and Clo
Indexes Cup and Clo
3,0
Octubre
2,5
2,0
1,5
1,0
Clo
Cup
2,5
2,0
1,5
1,0
0,5
0,5
0
2
4
6
8
10
12
14
16
18
20
22
0
UT
2
4
6
8
10
12
UT
Fig. 11
14
16
18
20
22
Jicamarca - ITEC – 2002 (HSA: Rz12= 102)
Variability indexes Cup and Clo
January
3,5
3,5
3,0
Indexes Cup and Clo
3,0
Indexes Cup and Clo
April
2,5
2,0
1,5
2,5
2,0
1,5
1,0
1,0
0,5
0,5
0
0
2
4
6
8
10
12
14
16
18
20
2
4
6
8
10
22
UT
July
3,5
14
16
18
20
22
October
3,5
3,0
3,0
2,5
Indexes Cup and Clo
Indexes Cup and Clo
12
UT
2,0
1,5
1,0
Clo
Cup
2,5
2,0
1,5
1,0
0,5
0,5
0
2
4
6
8
10
12
14
16
18
20
0
22
2
4
6
8
10
12
UT
UT
Fig. 12
14
16
18
20
22
Jicamarca – ITEC – 2002 (HSA) / 2006(LSA)
Variability index V%
January
April
220
200
200
180
180
160
160
140
140
120
120
V%
V%
220
100
100
80
80
60
60
40
40
20
20
0
0
0
2
4
6
8
10
12
14
16
18
20
0
22
2
4
6
8
10
UT
July
14
16
18
20
22
October
220
200
200
180
180
160
160
140
140
120
120
V%
V%
220
12
UT
100
100
80
80
60
60
40
2002
2006
40
20
20
0
0
2
4
6
8
10
12
14
16
18
20
0
22
0
UT
2
4
6
8
10
12
UT
Fig. 13
14
16
18
20
22
Comparisons between ITEC and IRITEC
predictions
Jicamarca - IRITEC predictions 2006 Rz= 16
January
April
40
35
35
30
30
25
25
ITEC[TECU]
ITEC[TECU]
40
20
15
10
20
15
10
5
5
0
0
2
4
6
8
10
12
14
16
18
20
0
22
0
2
4
6
8
10
UT
July
14
16
18
20
22
October
40
35
35
30
30
25
25
20
20
ITEC[TECU]
ITEC[TECU]
40
12
UT
15
10
15
10
5
5
0
0
-5
-5
-10
ITEC
IRI-NeQ
IRI-2001
IRI-2001corr
-10
0
2
4
6
8
10
12
14
16
18
20
22
UT
0
2
4
6
8
10
12
UT
Fig. 14
14
16
18
20
22
Jicamarca 2002 – ITEC / IRITEC
January
100
80
80
60
60
ITEC[TECU]
ITEC[TECU]
April
100
40
40
20
20
0
0
0
2
4
6
8
10
12
14
16
18
20
22
UT
80
ITEC[TECU]
60
40
20
0
0
2
4
6
8
10
12
2
4
6
8
10
12
UT
July
100
0
14
16
18
20
22
UT
Fig. 15
14
16
18
20
22
3. Topside Electron Density Profiles
Jicamarca 13/11/2001 (Rz12= 111)
UT 13.59
1000
950
950
900
900
850
850
800
800
750
h[km]
h[km]
UT 14.29
1000
700
750
700
650
650
600
600
550
550
500
500
450
450
0
2
4
6
8
10
12
14
16
5
18
20
22
24
26
28
0
30
2
4
6
8
10
12
UT 17.17
18
20
22
24
26
28
-3
UT 18.02
1000
950
950
900
900
850
850
800
800
750
h[km]
h[km]
16
Nx10 [cm ]
Nx10 [cm ]
1000
14
5
-3
700
650
IRI01C
IRINQ
IRI01
ISR
750
700
650
600
600
550
550
500
0
2
4
6
8
10
12
14
16
5
18
20
22
24
26
28
30
500
0
-3
Nx10 [cm ]
2
4
6
8
10
12
14
16
5
18
-3
Nx10 [cm ]
Fig. 16
20
22
24
26
28
30
30
Jicamarca 11/06/2002 (Rz12= 102)
UT 14.00
1000
950
900
900
850
850
800
800
750
750
700
700
h[km]
650
600
650
600
550
550
500
500
450
450
400
400
350
-2
0
2
4
6
8
5
10
12
14
350
16
-2
-3
0
2
Nx10 [cm ]
4
10
8
6
5
-3
Nx10 [cm ]
UT 16.00
1000
950
IRI01C
IRINQ
IRI01
ISR
900
850
800
750
h[km]
h[km]
UT 15.00
1000
950
700
650
600
550
500
450
400
0
2
4
6
8
10
5
12
-3
Nx10 [cm ]
Fig. 17
14
16
18
20
12
14
16
Jicamarca 15/04/2004 (Rz12= 42)
UT 05.49
1000
UT 11.35
1000
950
900
900
850
850
800
800
750
750
700
700
650
650
h[km]
h[km]
950
600
550
IRI01C
IRINQ
IRI01
ISR
600
550
500
500
450
450
400
400
350
350
300
300
250
0
2
4
6
5
8
10
-3
Nx10 [cm ]
0
2
4
6
5
-3
Nx10 [cm ]
Fig. 18
8
10
Jicamarca 28/06/2006 (Rz12= 16)
UT 20.00
1000
950
900
850
800
750
h[km]
700
650
600
550
500
450
400
350
0
2
4
6
5
8
10
-3
Nx10 [cm ]
UT 23.13
UT 22.42
1000
950
950
900
900
850
850
800
800
750
750
700
700
h[km]
h[km]
1000
650
650
600
600
550
550
500
500
450
450
400
400
350
IRI01C
IRINQ
IRI01
ISR
350
0
2
4
5
6
-3
0
2
4
5
Nx10 [cm ]
-3
Nx10 [cm ]
Fig. 19
6
Jicamarca 30/06/2006 (Rz12= 16)
950
950
900
900
850
850
800
800
750
750
700
h[km]
700
h[km]
UT 04.07
1000
UT 03.50
1000
650
600
650
600
550
550
500
500
450
450
400
400
350
350
300
300
0
0
2
4
5
2
6
4
5
6
-3
Nx10 [cm ]
-3
Nx10 [cm ]
950
950
900
900
850
850
800
800
750
750
700
700
h[km]
h[km]
UT 16.29
1000
UT 14.03
1000
650
600
IRI01C
IRINQ
IRI01
ISR
650
600
550
550
500
500
450
400
450
350
400
300
350
0
2
4
5
6
-3
0
2
4
5
Nx10 [cm ]
-3
Nx10 [cm ]
Fig. 20
6
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.
Tucuman.
and some comments about the new ionosone installed at
Operative ionospheric stations
Tucumán 2
(CIASURFRT and UTN)
La Plata
(GESA-UNLP)
B. San Martin
B. Belgrano
(IAA)
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 Scintillations
1:45 UT
45
Tucuman received power from PRN 02
Noche del 07/11/07
Satélite 2
Rcvd Pwr (dB)
40
22:45 LT
35
30
25
20
25
25,5
26
26,5
27
27,5
UT
1
1:30
2
2:30 UT
28
28,5
29
29,5
30
3:45 UT
50
Tucuman Recived Power from PRN 23
Satélite
Noche del 23
16/Abril/2008
45
0:45 LT
Rcvd Pwr (dB)
40
35
30
25
20
27
27,1
27,2
27,3
27,4
27,5
UT
27,6
27,7
27,8
27,9
28
4:00 UT
50
Tucuman Received Power from PRN 19
Noche del 16/Abril/2008
Satélite 13
45
1:00 hs LT
Rcvd Pwr (dB)
40
35
30
25
20
27,5
28
28,5
UT
29
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 additional
stratification 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 lowfrequency 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!!