“ EQUATORIAL TEC OVER SOUTH AMERICAN SECTOR WITH DIFFERENT MAGNETIC DECLINATION ANGLES”

“EQUATORIAL TEC OVER SOUTH AMERICAN SECTOR WITH DIFFERENT MAGNETIC

DECLINATION ANGLES”

P. A. B. Nogueira*1, M. A. Abdu1 , J. R. Souza1, I. S. Batista1, E. B. Shume1, R.Y.C. Cueva1, C.V. Ely1, G. J. Bailey2.  1Instituto Nacional de Pesquisas Espaciais, Caixa Postal 515, São José dos Campos, SP, Brasil;2Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH, U.K

Abstract TEC longitudinal variation; Magnetic Declination Angles Dependence;

São Luís (2.33° S, 315.8ºE, declination = -19o) in Brazil

Arequipa (16.5°S, 288.5ºE, declination = 0.5o) in Perú TEC variations for three solar activity levels; TEC values over São Luís are larger than that

ones over Arequipa; SUPIM model has been used to investigate

such difference.

TEC Longitudinal Variation

It is well known: TEC data show strong annual/semiannual, solar

cycle, and 27-days variations.

However, it is not known: How is the TEC variation associated with

different magnetic declination angles?

TEC Temporal Pattern and Magnetic Declination Angle Effect It is well known that the magnetic

declination angle may affect: The PRE vertical ExB drift (Batista et al.,

1986);

The plasma bubble development (Abdu et al., 1981);

EEJ pattern (Shume et al., 2010).

GPS Receivers Station

Arequipa: GPS ReceiverROGUE SNR-8000

São Luís GPS Receiver:Turbo Rogue ICS-400Z Allen-Osborne Associates Receivers.

TEC Seasonal Variation- 2001

Local Time Comparison: 0 – 6 LT

Local Time Comparison: 6 – 12 LT

Local Time Comparison: 12 – 18 LT

Local Time Comparison: 18 – 24 LT

foF2 Seasonal Variation- 2001

SUPIM MODEL

0 30 60 90 120 150 180 210 240 270 300 330 3600

3

6

9

12

15

18

21

24

LOCA

L TI

ME

DOY

0

50,00

100,0

150,0

180,0

SAO LUIS - TEC SUPIM (HWM-93) - 2001

0 30 60 90 120 150 180 210 240 270 300 330 3600

3

6

9

12

15

18

21

24

LOCA

L TI

ME

DOY

0

50,00

100,0

150,0

180,0

AREQUIPA - TEC SUPIM (HWM-93) - 2001

0 30 60 90 120 150 180 210 240 270 300 330 3600

3

6

9

12

15

18

21

24

LOCA

L TI

ME

DOY

0

50,00

100,0

150,0

180,0

SAO LUIS - TEC SUPIM (HWM-07) - 2001

0 30 60 90 120 150 180 210 240 270 300 330 3600

3

6

9

12

15

18

21

24

LOCA

L TI

ME

DOY

0

50,00

100,0

150,0

180,0

AREQUIPA - TEC SUPIM (HWM-07) - 2001

Observational Data vs Ionospheric Modelling

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

15

SL AREQ

46

74 105

135

2001

166

196 227

258 288

319

LOCAL TIME

TEC

349

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

15

SL AREQ

46

74 105

135

2001 - SUPIM Results

166

HWM-93SOLAR2000S&F 1999NRLMSISE-00

196 227

2580 3 6 9 12 15 18 21 240

50100150

288

0 3 6 9 12 15 18 21 24050

100150

319

LOCAL TIME

TEC

349

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

15

Observational Modelling

46

74 105

135

2001 - AREQ

166

HWM-2007SOLAR2000S&F 1999NRLMSISE-00

196 227

258 288

319

LOCAL TIME

TEC

349

Observational Data vs Ionospheric Modelling

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

0 3 6 9 12 15 18 21 24050

100150

15

Observational Modelling

46

74 105

135

2001 - SL

166

196 227

258 288

319

LOCAL TIME

TEC

HWM-2007SOLAR2000S&F 1999NRLMSISE-00

349

TEC Seasonal Variation- 2005

TEC Seasonal Variation - 2007

Changing SL GPS Receiver

São Luís: GPS ReceiverNetR5 - 4651K03649

Arequipa: GPS ReceiverROGUE SNR-8000

TEC Semiannual Variation Period

Summary

TEC semiannual variation during daytime was establish, with two peak located over the equinoctial condition.

The period of the TEC semiannual variation is better represented over high solar activity with period equal to ~185 days.

The highest TEC magnitude was found over São Luís, the main reason for this feature could be attributed to the large negative declination angle over Brazil.

ACKNOWLEDGEMENT

Paulo A. B. Nogueira acknowledges the supports from CNPQ for his PhD program.