THE COMPUTATION OF THE GEOID MODEL IN THE STATE OF SÃO PAULO USING TWO METHODOLOGIES AND GOCE MODELS

The purpose of this manuscript is to compute and to evaluate the geoid model in the State of São Paulo from two methodologies (Stokes’ integral through the Fast Fourier Transform - FFT and Least Squares Collocation – LSC). Another objective of this study is to verify the potentiality of GOCE-based. A special attention is given to GOCE mission. The theory related to Stokes’ integral and Least Squares Collocation is also discussed in this work. The spectral decomposition was employed in the geoid models computation and the long wavelength component was represented by EGM2008 up to degree and order 150 and 360 and GOCE-based models up to 150. The models were compared in terms of geoid height residual and absolute and relative comparisons from GPS/leveling and the results show consistency between them. In addition, a comparison in the mountain regions was carried out to verify the methodologies behavior in this area; the results showed that LSC is less consistent than FFT

Using geotechnologies for mapping water storage changes in the pampeana region from grace data

El campo gravitatorio terrestre no permanece constante, sino que varía en el tiempo debido a diversos factores como la redistribución de masas durante el ciclo hidrológico. La misión satelital GRACE (Gravity Recovery and Climate Experiment), provee datos acerca de la variación temporal del campo gravitatorio terrestre con una resolución espacial de aproximadamente 400 km. Debido a la relación directa entre gravedad y masa, es posible obtener las variaciones del almacenamiento de agua a partir del espesor equivalente de agua (EWH por sus siglas en inglés: Equivalent Water Height). El objetivo de este trabajo es el análisis regional de la variación del almacenamiento de agua a partir de la representación de los cambios espaciales y temporales del EWH derivados de GRACE, para el período 2003-2010 en la cuenca del río Salado, ubicada en la Región Pampeana. Para esta representación se utilizó el software GMT (Generic Mapping Tools) de código abierto, el cual permitió simplificar y automatizar el proceso cartográfico mediante scripts, creando todos los mapas en una sola aplicación. Los resultados de GRACE fueron validados con datos de precipitaciones del GPCP (Global Precipitation Climatology Project), humedad del suelo del GLDAS (Global Land Data Assimilation System) y mediciones de la cota hidrométrica en la Laguna La Picasa, ubicada en la cuenca del río Salado. GRACE detectó significativas variaciones del espesor equivalente de agua en el período bajo estudio, las que pueden asociarse a precipitaciones máximas y mínimas ocurridas en la región. Las señales de EWH y cota hidrométrica presentaron un comportamiento similar y una tendencia negativa en el período 2002-2009. La correlación entre ambas señales resultó ser mayor al 75%, indicando un buen ajuste entre variables geofísicas diferentesThe Earth’s gravity field does not remain constant but changes over time depending on several factors such as redistribution of the masses due to hydrological cycles. The GRACE (Gravity Recovery and Climate Experiment) satellite mission provides time-variable readings of variations in the Earth’s gravity field at a spatial resolution of ~400 km. Because of the direct relationship between mass and gravity, it is possible to obtain the related changes in water storage from the Equivalent Water Height (EWH). The aim of this work is to analyze the regional changes in water storage from a representation of the spatio-temporal EWH variations obtained from GRACE solutions for the period 2003-2010 in the Salado river basin, located in the Pampeana Region of Argentina. The GMT (Generic Mapping Tools) open-source software was used for this representation, as it allows for simplification and automation of the mapping process using scripts to create maps all within a single application. Afterwards, GRACE results were validated by comparison with GPCP (Global Precipitation Climatology Project) rainfall data as well as GLDAS (Global Land Data Assimilation System) soil moisture and hydrometric heights of the Picasa Lagoon in the Salado River basin. This mission detected significant EWH variations in the period under study, which could be associated with maximum and minimum precipitations that occurred in the region. The EWH and hydrometric height signals both showed a similar behavior and a negative trend within the period 2002-2009. The correlation between both signals was greater than 75%, showing a good adjustment between different geophysical variablesFil: Pereira, Ayelen. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cornero, Cecilia. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pacino, Maria Cristina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oliveira Cancoro de Matos, Ana Cristina. Universidade de Sao Paulo; Brasi

VALIDATION OF THE LAND WATER STORAGE FROM GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) WITH GAUGE DATA IN THE AMAZON BASIN

The Amazon basin is a region of constant scientific interest due to its environmental importance and its biodiversity and climate on a global scale. The seasonal variations in water volume are one of the examples of topics studied nowadays. In general, the variations in river levels depend primarily on the climate and physics characteristics of the corresponding basins. The main factor which influences the water level in the Amazon Basin is the intensive rainfall over this region as aconsequence of the humidity of the tropical climate. Unfortunately, the Amazon basin is an area with lack of water level information due to difficulties in access for local operations. The purpose of this study is to compare and evaluate the Equivalent Water Height (Ewh) from GRACE (Gravity Recovery And Climate Experiment) mission, to study the connection between water loading and vertical variations of the crust due to the hydrologic. In order to achieve this goal, the Ewh is compared with in-situ information from limnimeter. For the analysis it was computed the correlation coefficients, phase and amplitude of GRACE Ewh solutions and in-situ data, as well as the timing of periods of drought in different parts of the basin. The results indicated that vertical variations of the lithosphere due to water mass loading could reach 7 to 5 cm per year, in the sedimentary and flooded areas of the region, where water level variations can reach 10 to 8 m

Study of water storage variations at the Pantanal wetlands area from GRACE monthly mass grids

The continental water storage is significantly influenced by wetlands, which are highly affected by climate change and anthropogenic influences. The Pantanal, located in the Paraguay river basin, is one of the world´s largest and most important wetlands because of the environmental biodiversity that represents. The satellite gravity mission GRACE (Gravity Recovery And Climate Experiment) provided until 2017 time-variable Earth?s gravity field models that reflected the variations due to mass transport processes -like continental water storage changes- which allowed to study environments such as wetlands, at large spatial scales. The water storage variations for the period 2002-2016, by using monthly land water mass grids of Total Water Storage (TWS) derived from GRACE solutions, were evaluated in the Pantanal area. The capability of the GRACE mission for monitoring this particular environment is analyzed, and the comparison of the water mass changes with rainfall and hydrometric heights data at different stations distributed over the Pantanal region was carried out. Additionally, the correlation between the TWS and river gauge measurements, and the phase differences for these variables, were also evaluated. Results show two distinct zones: high correlations and low phase shifts at the north, and smaller correlation values and consequently significant phase differences towards the south. This situation is mainly related to the hydrogeological domains of the area.Fil: Pereira, Ayelen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografía; ArgentinaFil: Cornero, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografía; ArgentinaFil: Oliveira Cancoro de Matos, Ana Cristina. Universidade de Sao Paulo; BrasilFil: Pacino, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografía; ArgentinaFil: Blitzkow, Denizar. Universidade de Sao Paulo; Brasi

Detection of total water mass changes in the Patagonian glaciers area by satellite gravimetry

Despite present efforts to better understand glacier changes and their trends, the satellite gravimetry is a powerful tool still not applied in-depth to study relatively large areas in the Andes of Argentina and Chile. In this work, the Patagonian Icefield mass variations are analyzed together with the decrease trends of the ice layer in the region. The purpose of this study is to demonstrate the GRACE satellite mission (Gravity Recovery and Climate Experiment) ability to detect water storage changes over the glaciers area. Furthermore, the variations of the hydrometric level in some Patagonian lakes were monitored by combining satellite altimetry data and in situ measurements with the observed water mass variations. Data retrieved from GRACE were used to estimate gravity trends; and high-resolution GRACE CSR RL05 mascon solutions were used to analyze the icefields water storage change in the region under study for the 2002-2017 period. Virtual stations from satellite altimetry obtained from a lake database and hydrometric height data from in situ stations, located at Patagonian lakes in Argentina and Chile, were also used in order to compare the TWS from GRACE to the water level of the specific lakes. Additionally, correlation coefficients were determined at each station. The results show a significant water storage decrease in the Icefield area, and they also demonstrate that the ice melt in southern Patagonia (of about 6 cm/year) tends to be more pronounced than in the northern region.La gravimetría satelital es una herramienta que aún no se aplica en profundidad para estudiar áreas relativamente extensas en los Andes de Argentina y Chile, a pesar de los esfuerzos actuales para lograr una mejor comprensión de los cambios en los glaciares y sus tendencias. En este trabajo se analizan las variaciones de masa en los Hielos Patagónicos junto con las tendencias de decrecimiento en la región. El objetivo es demostrar la capacidad de la misión satelital GRACE (Gravity Recovery and Climate Experiment) para detectar los cambios en el almacenamiento de agua en áreas glaciarias. Además, se monitorearon las variaciones del nivel hidrométrico en lagos patagónicos, combinando datos de altimetría satelital y mediciones in situ con los cambios de masa de agua observados. Para ello, se utilizaron datos GRACE para estimar la tendencia de la gravedad; y fueron usadas soluciones "mascons" de GRACE CSR RL05 de alta resolución, para analizar los cambios en el almacenamiento de agua de los campos de hielo en la región para el período 2002-2017. Se utilizaron estaciones virtuales de altimetría satelital, además de información de altura hidrométrica de estaciones localizadas en lagos de la Patagonia en Argentina y Chile, con el fin de comparar el TWS de GRACE con el nivel de agua. Adicionalmente, se calcularon los coeficientes de correlación en cada estación. Los resultados manifiestan una disminución significativa del almacenamiento de agua en la zona del Campo de Hielo, y además muestran que los Hielos Patagónicos Sur tienen una tendencia de derretimiento de las masas de hielo más pronunciada que en la región del norte, de aproximadamente 6 cm/año.Fil: Pereira, Ayelen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; ArgentinaFil: Cornero, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; ArgentinaFil: Oliveira Cancoro de Matos, Ana Cristina. Universidade de Sao Paulo; Brasil. Centro de Estudos de Geodesia.; BrasilFil: Pacino, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; ArgentinaFil: Blitskow, Denizar. Universidade de Sao Paulo; Brasil. Centro de Estudos de Geodesia.; Brasi

The computation of the geoid model in the state of São Paulo using two methodologies and GOCE models

The purpose of this manuscript is to compute and to evaluate the geoid model in the State of São Paulo from two methodologies (Stokes' integral through the Fast Fourier Transform - FFT and Least Squares Collocation - LSC). Another objective of this study is to verify the potentiality of GOCE-based. A special attention is given to GOCE mission. The theory related to Stokes' integral and Least Squares Collocation is also discussed in this work. The spectral decomposition was employed in the geoid models computation and the long wavelength component was represented by EGM2008 up to degree and order 150 and 360 and GOCE-based models up to 150. The models were compared in terms of geoid height residual and absolute and relative comparisons from GPS/leveling and the results show consistency between them. In addition, a comparison in the mountain regions was carried out to verify the methodologies behavior in this area; the results showed that LSC is less consistent than FFT

VALIDATION OF THE LAND WATER STORAGE FROM GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) WITH GAUGE DATA IN THE AMAZON BASIN

The Amazon basin is a region of constant scientific interest due to its environmental importance and its biodiversity and climate on a global scale. The seasonal variations in water volume are one of the examples of topics studied nowadays. In general, the variations in river levels depend primarily on the climate and physics characteristics of the corresponding basins. The main factor which influences the water level in the Amazon Basin is the intensive rainfall over this region as a consequence of the humidity of the tropical climate. Unfortunately, the Amazon basin is an area with lack of water level information due to difficulties in access for local operations. The purpose of this study is to compare and evaluate the Equivalent Water Height (Ewh) from GRACE (Gravity Recovery And Climate Experiment) mission, to study the connection between water loading and vertical variations of the crust due to the hydrologic. In order to achieve this goal, the Ewh is compared with in-situ information from limnimeter. For the analysis it was computed the correlation coefficients, phase and amplitude of GRACE Ewh solutions and in-situ data, as well as the timing of periods of drought in different parts of the basin. The results indicated that vertical variations of the lithosphere due to water mass loading could reach 7 to 5 cm per year, in the sedimentary and flooded areas of the region, where water level variations can reach 10 to 8 m.Brazilian National Research Council of Scientific and Technological Development (CNPq)Brazilian National Research Council of Scientific and Technological Development (CNPq

Determination of a static gravimetric geoid for the Santa Fe province, Argentina

La determinación del geoide se ha convertido en la actualidad en uno de los objetivos fundamentales de la Geodesia, para dar lugar a una solución del problema altimétrico. Ésta problemática puede ser considerada en el contexto del modelado del campo de gravedad terrestre, ya que todos los métodos decálculo involucran de una u otra manera su conocimiento. El presente trabajo consiste en el cálculo de cuatro modelos de geoide gravimétrico estático para la provincia de Santa Fe (Argentina) y en su posterior validación con información terrestre de alturas elipsoidales (GNSS) y de Redes de Nivelación (RN). La metodología aplicada consistió en la técnica Remover-Restaurar, incorporando diversos Modelos de Geopotencial Global (MGG), junto con 39,771 observaciones gravimétricas terrestres. El cálculo de los modelos fue realizado con el paquete de programas canadiense SHGEO (Stokes-Helmert Geoid Software), desarrollado por el Departamento de Geodesia e Ingeniería Geomática de la Universidad de New Brunswick, Canadá. Los modelos de geopotencial global GO_CONS_GCF_2_DIR_R5 y EIGEN6C4, limitados hasta grado y orden 200 y 300, fueron utilizadoscomo referencia para el cálculo. Se utilizó además, el modelo digital de terreno SAM3s_v2 y el modelo de gravedad oceánica DTU10. El análisis estadístico se realizó con 100 puntos de doble información altimétrica (GNSS sobre nivelación), resultando el modelo calculado con base GO_CONS_GCF_2_DIR_R5 hasta grado y orden 300 el de mayor consistencia. El mismo fue el que presentó el mínimo valor medio de las alturas geoidales geométricas (NGNSS-RN) respecto a las obtenidas en el modelo calculado (N) (0.096m), y un RMS de dicha diferencia de 0.221 m.At present, the determination of the geoid has become one of the fundamental Geodesy objectives, in order to provide a solution for the altimetric problem. This can be considered in the context of the terrestrial gravity field modeling, since all the calculation methods involve in one way or another its knowledge. This work consists in the calculation of four static gravimetric geoid models for the province of Santa Fe (Argentina) and its validation with terrestrial information from ellipsoidal heights (GNSS) and Leveling Networks (RN). The applied methodology in this investigation was the Remove-Restore technique, and various Global Geopotential Models (MGG) along with 39,771 terrestrial gravimetric observations were incorporated in the study. The calculation of the models was accomplished with the Canadian SHGEO software package (Stokes-Helmert Geoid Software), developed by the Department of Geodesy and Geomatic Engineer of the University of New Brunswick, Canada. The global geopotential models GO_CONS_GCF_2_DIR_R5 and EIGEN6C4, limited to degree and order 200 and 300, were used as a reference for the calculation. Also, the SAM3s_v2 digital terrain model and the DTU10 oceanic gravity model were used. The statistical analysis was performed with 100 points with double altimetric information (GNSS on leveling), resulting the model based on the GO_CONS_GCF_2_DIR_R5 up to grade and order 300 the one with greater consistency. This model also presented the minimum geoidal height mean values (NGNSS-RN) with respect to those obtained in the calculated model (N) (0.096m), and an RMS of the difference of 0.221 m.Fil: Cornero, Cecilia. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Pereira, Ayelen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; ArgentinaFil: Varela, Mauricio Alejandro. Universidad de Costa Rica; Costa RicaFil: Oliveira Cancoro de Matos, Ana Cristina. Universidade de Sao Paulo; BrasilFil: Blitzkow, Denizar. Universidade de Sao Paulo; BrasilFil: Pacino, Maria Cristina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin

VALIDAÇÃO DO MAPGEO2010 E COMPARAÇÃO COM MODELOS DO GEOPOTENCIAL RECENTES

Este trabalho visa apresentar a metodologia de cálculo e analisar o resultado do modelo de alturas geoidais para o Brasil. O mesmo abrange a área compreendida pelas latitudes de 6oN e 35oS e pelas longitudes de 75oW e 30oW. Os dados gravimétricos terrestres foram atualizados com as mais recentes medições no Brasil e seus países vizinhos. As anomalias completas de Bouguer e de Helmert sobre a superfície terrestre foram calculadas  através do pacote canadense SHGEO. A componente de curto comprimento de onda foi estimada através da integral modificada de Stokes utilizando a técnica FFT. O modelo do geopotencial EGM2008 serviu como modelo de referência restrito ao grau e ordem 150. Foram utilizadas 844 observações GPS sobre a rede de nivelamento geométrico para comparar com o modelo geoidal obtido. As anomalias de altura adicionadas de um termo de correção dependente da topografia derivadas do EGM2008 (grau 2190 e ordem 2159), GO_CONS_GCF_2_DIR_R2 (grau e ordem 240), GOCO02S (grau e ordem 250), EIGEN 51C (grau e ordem 359) e EIGEN 6C (grau e ordem 1420), bem como as alturas geoidais derivadas do MAPGEO2004 (antigo modelo oficial do IBGE) também foram comparadas com os pontos GPS sobre nivelamento