Absolute Gravity Networks in Absolute Gravity Networks in South America - First Results South America - First Results and perspectives and perspectives Denizar Blitzkow Ana Cristina O. Cancoro de Matos ([email protected]) EPUSP - Escola Politécnica da Universidade de São Paulo, Brasil EPUSP EPUSP Escola Politécnica da Universidade de São Paulo Escola Politécnica da Universidade de São Paulo Worshop MicrogLacoste Sep 2014 Sep 2014 1
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Absolute Gravity Networks in South America - First Results and perspectives Denizar Blitzkow Ana Cristina O. Cancoro de Matos ([email protected]) EPUSP -
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Absolute Gravity Networks in South Absolute Gravity Networks in South
America - First Results and America - First Results and
EPUSP - Escola Politécnica da Universidade de São Paulo, Brasil
EPUSPEPUSPEscola Politécnica da Universidade de São PauloEscola Politécnica da Universidade de São Paulo
Worshop MicrogLacosteSep 2014Sep 2014
1
Earth Tide ModelEarth Tide Model
A project in BrazilA project in Brazilunder the coordination ofunder the coordination of
EPUSP/LTG and CENEGEO EPUSP/LTG and CENEGEO (Centre for Geodesy Studies) (Centre for Geodesy Studies)
to establish an Earth Tide Model to establish an Earth Tide Model
Support:GEORADAR Levantamentos Geofísicos S.A.
The first phase of the project is intended to achieve the determination of a preliminary model for the Earth tide in São Paulo state (four stations).
The project aims to establish 9 stations well distributed in Brazil:
One of long term in Manaus, Amazon.
Eight others in a sequence of four years operation in different places. In all cases a permanent GPS receiver is available.
gPhone Micro-g LaCoste 105 – Presidente Prudente - UNESP
During the year 2012 the two gPhones were installed respectively:1. University of São Paulo, São Paulo city;2. Abrahão de Moraes observatory, Valinhos city.The places belong to the Institute of Astronomy, Geophysics and Atmospheric Sciences of the University of São Paulo (IAG-USP).
Year 2013/20141. Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), in Presidente Prudente;2. The ocean research base Dr. João de Paiva Carvalho, Oceonographic Institute, University of São Paulo (IO-USP), located in Cananeia.3. University of São Paulo, São Paulo city;
We are using TSOFT and ETERNA softwares for the preparation of the data and for tidal analysis. After many problems for processing teh data we came to important improvement very recently.
The atmospheric pressure showed a perfect behavior considering that it varies inversely proportional to the gravity. A regression analysis applied to the observed pressure data resulted in a coefficient of 2.69. It is necessary to remove this effect from the gravity data.
The drift of the equipment was very small. The estimation of the drift by a regression analysis resulted in the following coefficients for the first order linear equation:
g = 5.58158 x10-13 T - 0.000224227whereg gravity valueT time
This drift can be studied with the absolute gravitymeter A-10, now available.
IAG-USP(January to October, 2012)
ambient pressure
data survey
Latitude:-25.0202 deg, longitude:-47.9250 deg, 20130314...20140108 Hartmann+Wenzel (1995) TGP Rigid Earth model used.Sampling interval: 300. s Numerical filter is N05M05M2 with 2001 coefficients.
Dr. João de Paiva Carvalho Observatory/IO – Cananéia/SP
Latitude:-25.0202 deg, longitude:-47.9250 deg 20130314...20140108 Hartmann+Wenzel (1995) TGP, Rigid Earth model used.Sampling interval: 300. s Numerical filter is N05M05M2 with 2001 coefficients.
Standard deviation: 16.41 nm/s**2
Absolute GravityAbsolute GravityA project in Brazil and ArgentinaA project in Brazil and Argentina
under the coordination ofunder the coordination of EPUSP/LTG and CENEGEO EPUSP/LTG and CENEGEO
(Centre for Geodesy Studies) (Centre for Geodesy Studies)
Support:
IGC (Instituto Geográfico e Cartográfico) in Brazil IGN (Instituto Geográfico Nacional) in Argentina
Importance of establishing more absolute stations in South America.
Source:http://bgi.get.obs-mip.fr/agrav-meta/
Absolute gravitymeter Micro-g LaCoste A-10/32
Astronomical ObservatoryValinhos - SP
The A-10 absolute gravimeter is working around Brazil and Argentina establishing fundamental gravity points with high precision and it will be used for controlling the drift of the gPhone when necessary.
Projects:
1. São Paulo state project (2013/2014):
- Stations established: Franca, Jaboticabal, Lins, São Carlos, São José do Rio Preto, Valinhos.- Reobservation of São Paulo, Ubatuba and Cananéia existing absolute points.- New stations will be established in Araçatuba, Botucatu, Cachoeira Paulista, Campinas, Dracena, Itapeva, Ilha Solteira, Tupã, Ourinhos, Presidente Prudente.
Results – UNESP Jaboticabal Station
Program interface with the result of 1 cycle and 120 drops "free fall"
Screen with the results
It is considered a very good
measurements, with a few
rejections in red. At each station 8
cycles of 120 drops are carried out.
6
)212( surveyfinal ggradientnewg
5,70* .
difHeight
gggradientnew topobase
The gravity gradient is observed in each station by measurements in two points
with the possible difference of height available. CG5 is used for the gradient
measurement. We don’t have a platform. In a first step the normal gradient
0.30 mGal/m is used. In a new processing the real gradient is taking into
consideration.
where:
Calculating the g value
Results of Sao Paulo state absolute stations
City ID Latitude Longitude final g(μGal)Jaboticabal JABOTICABAL -21.24056 -48.28750 978512730S. J. do R.
PretoS J R PRETO -20.78417 -49.36250 978516376
Lins LINS -21.67528 -49.75167 978589550Franca FRANCA -20.53583 -47.39917 978393382
São Carlos SÃO CARLOS -22.01139 -47.89667 978490175São Paulo 18_11_13_IAG -23.55900 -46.73400 978642071Valinhos VALINHOS -23.55889 -46.73389 978563961
Results of Parana state absolute station
City ID Latitude Longitude final g(μGal)Foz de Iguaçu 3FRONT -25.59028 -54.59028 978916210
JABOTICABAL S J R PRETO LINS FRANCA SÃO CARLOS SÃO PAULO SÃO PAULO 2 VALINHOSG GROUND (microGal) 978513400 978516524 978590004 978393162 978489991 978641940 979999146 980000145G TOP (microGal) 978513021 978516271 978589801 978392989 978489795 978641746 979998960 979999834HEIGHT (cm) 120 97 73 55 65 67 67 80GRAD. (microGal/cm) 3,1583 2,6082 2,7808 3,1455 3,0154 2,8955 2,7761 3,8875G ABS. (microGal) 978512508 978516192 978589354 978393160 978489963 978641871 978641871 978563687New GRAD (microGal) 223 184 196 222 213 204 196 274,07
G FINAL COR. (microGal) 978512730 978516376 978589550 978393382 978490175 978642075 978642066 978563961
Gravity Gradient in São Paulo
FOZ DO IGUA.G GROUND (microGal) 978915970G TOP (microGal) 978915797HEIGHT (cm) 65GRAD. (microGal/cm) 2,6615G ABS. (microGal) 978916023GRAD. NEW (microGal) 188G FINAL COR. (microGal) 978916210
Garavity Gradient in Paraná
Station Old survey G value New survey G value
CG5-513
IAG USP Absolute 978641.82 (Absolute G value station IAG USP)
--------------------------------
121582 - Sorocaba B 978652.67 (Reference station determined by ON with L&R
gravimeter)
978652.64 (Determined by Scintrex CG5 gravimeter)
CG5 - 808
IAG USP Absolute 978641.82 (G value of the IAG USP Absolute station)
-------------------------------
11776 – Porto Ferreira B 978546.54 (Reference station determined by ON with L&R
gravimeter)
978546.47 (Determined by Scintrex CG5 gravimeter)
12176 – Ituverava B 978467.16 (Reference station determined by ON with L&R
gravimeter)
978467.05 (Determined by Scintrex CG5 gravimeter)
CG5 - 757
IAG USP Absoluta 978641.82 (G value of the IAG USP Absolute station) --------------------------------
12176 – Ituverava B 978467.16 (Reference station determined by ON with L&R gravimeter)
978466.98 (Determined by Scintrex CG5 gravimeter)
CG5 - 808
Lins Absoluta 978589.35 (G value of the Absolute station determined by USP)
978589.41 (Determined by the IAG USP with L&R gravimeter)
Franca PC 978394.62 (Departure of Franca absolute station - Determined by
Scintrex CG5 gravimeter)
978394.51 (Determined by IBGE - Departing from ON station in
Porto Ferreira B - Determined by Scintrex CG5 gravimeter)
Comparative Table
Monography for Jaboticabal station - UNESP
0004 UNESP JABOTICABAL BRASIL
Número da Estação Nome da Estação País
ESQUEMAEstado :
Estabelecido por :
Data :
Valor de G:
Coordenadas:
DESCRIÇÃOUtilizou-se um gradiente de 0,317 mGal/m para reduzir o valor obtido na altura da câmera de queda livre para o piso.
Detalhe
Panorama
SÃO PAULO
LTG / IGC / USP
03 / 10 / 2013
978512523,12 ± 11 μGal
Lat 21º 14’ 26” S
H = 596 m
Lon 48º 17’ 15” W
8
2. Argentina project:
2 campaigns: North (17 points) South (15 points)
Results of absolute stations in Argentina1st. Campaign (17 points)
10
City ID Station Latitude Longitude final g(μGal)Colon GGIL -32.21656 -58.14703 979517779
The work shows the initial efforts to implement absolute gravimetric networks in South America.
We had many problems with A-10 since the begining. Derek visited us twice. In a first visit to set up A-10. He realized that it was not working. A repair has been necessary. The campaign in Argentina was very complicated: hot in the north (40º C) and very cold in the south.After the first campaign in Argentina we had problem with the two pendulums. The oil inside was lost. They have been substituted. Immediately after the autolevel switch failed. In all cases Derek and Brian were very helpful, At the moment the problem is with low fringes message. With the training I had in the last two days I could see the many different points I have to check. I hope to do it in my way back to Brazil and continue with my projects.
- Network in the sate of São Paulo, Paraná and Minas Gerais in Brazil.- A network in Venezuela and Ecuador.
- Network in the state of Paraná
We do not have yet a consistency on the order of 10μGal in our measurements. In Argentina we reoccupied a few points with BGI equipement. The differences are over 10 μGal.
We have a few absolute stations in Brazil established in the past by the group in Hannover and after by NGS (Daniel). I am now doing some comparisons.
AcknowledgementsAcknowledgements
The authors acknowledge Instituto Geográfico e Cartográfico (IGC) of São Paulo
to have available the absolute gravimeter for the realization of networks and the
Instituto Geográfico Nacional of Argentina that cooperated with the campaigns.