scholarly journals Monitoring mass changes in the Volta River basin using GRACE satellite gravity and TRMM precipitation

2012 ◽  
Vol 18 (4) ◽  
pp. 549-563 ◽  
Author(s):  
Vagner G. Ferreira ◽  
Zheng Gong ◽  
Samuel A. Andam-Akorful
Keyword(s):  
River Basin ◽  
Gravity Data ◽  
West African ◽  
Rainfall Time Series ◽  
Tropical Rainfall Measurement Mission ◽  
Satellite Gravity ◽  
Rainfall Events ◽  
The North ◽  
Trmm Precipitation ◽  
Grace Satellite

GRACE satellite gravity data was used to estimate mass changes within the Volta River basin in West African for the period of January, 2005 to December, 2010. We also used the precipitation data from the Tropical Rainfall Measurement Mission (TRMM) to determine relative contributions source to the seasonal hydrological balance within the Volta River basin. We found out that the seasonal mass change tends to be detected by GRACE for periods from 1 month in the south to 4 months in the north of the basin after the rainfall events. The results suggested a significant gain in water storage in the basin at reference epoch 2007.5 and a dominant annual cycle for the period under consideration for both in the mass changes and rainfall time series. However, there was a low correlation between mass changes and rainfall implying that there must be other processes which cause mass changes without rainfall in the upstream of the Volta River basin.

scholarly journals Water Storage, Net Precipitation, and Evapotranspiration in the Mackenzie River Basin from October 2002 to September 2009 Inferred from GRACE Satellite Gravity Data

2011 ◽  
Vol 12 (3) ◽  
pp. 467-473 ◽  
Author(s):  
E. Morrow ◽  
J. X. Mitrovica ◽  
G. Fotopoulos
Keyword(s):  
River Basin ◽  
River Discharge ◽  
Linear Trend ◽  
Gravity Data ◽  
Water Storage ◽  
Model Errors ◽  
Satellite Gravity ◽  
Mackenzie River Basin ◽  
Grace Satellite ◽  
Mackenzie River

Abstract Gravity Recovery and Climate Experiment (GRACE) satellite gravity data are used to determine the variability of terrestrial water storage within the Mackenzie River basin from October 2002 to September 2009. During that period, it is estimated that there is no significant (7 yr) linear trend in the water storage after having accounted for postglacial rebound using the ICE-5G (VM2) ice sheet and Earth viscosity model. Errors in this model may alter this conclusion. The GRACE gravity data are also combined with precipitation and river discharge datasets to estimate trends in net precipitation and evapotranspiration in the basin. Net precipitation is seen to have a significant trend with a corresponding increase in river discharge. Evapotranspiration was found to be constant over the study period.

The experimental geoid 2020 – the first joint geoid model for the North American and Pacific Geopotential Datum 

2021 ◽  
Author(s):  
Yan Ming Wang ◽  
Xiaopeng Li ◽  
Kevin Ahlgren ◽  
Jordan Krcmaric ◽  
Ryan Hardy ◽  
...  
Keyword(s):  
North American ◽  
Gravity Data ◽  
The United States ◽  
Geodetic Survey ◽  
Airborne Gravity ◽  
Data Sets ◽  
National Geodetic Survey ◽  
Geoid Model ◽  
Satellite Gravity ◽  
The North

<p>For the upcoming North American-Pacific Geopotential Datum of 2022, the National Geodetic Survey (NGS), the Canadian Geodetic Survey (CGS) and the National Institute of Statistics and Geography of Mexico (INEGI) computed the first joint experimental gravimetric geoid model (xGEOID) on 1’x1’ grids that covers a region bordered by latitude 0 to 85 degree, longitude 180 to 350 degree east. xGEOID20 models are computed using terrestrial gravity data, the latest satellite gravity model GOCO06S, altimetric gravity data DTU15, and an additional nine airborne gravity blocks of the GRAV-D project, for a total of 63 blocks. In addition, a digital elevation model in a 3” grid was produced by combining MERIT, TanDEM-X, and USGS-NED and used for the topographic/gravimetric reductions. The geoid models computed from the height anomalies (NGS) and from the Helmert-Stokes scheme (CGS) were combined using two different weighting schemes, then evaluated against the independent GPS/leveling data sets. The models perform in a very similar way, and the geoid comparisons with the most accurate Geoid Slope Validation Surveys (GSVS) from 2011, 2014 and 2017 indicate that the relative geoid accuracy could be around 1-2 cm baseline lengths up to 300 km for these GSVS lines in the United States. The xGEOID20 A/B models were selected from the combined models based on the validation results. The geoid accuracies were also estimated using the forward modeling.</p>

scholarly journals Efficient Use of Satellite Gravity Anomalies for mapping the Great Sumatran Fault in Aceh Province

2019 ◽  
Vol 9 (02) ◽  
pp. 61
Author(s):  
Muhammad Yanis ◽  
Marwan Marwan ◽  
Nazli Ismail
Keyword(s):  
Gravity Data ◽  
Gravity Anomalies ◽  
Geological Structure ◽  
Geological Mapping ◽  
Capital City ◽  
Satellite Gravity ◽  
Alluvial Deposits ◽  
The North ◽  
Aceh Province ◽  
Tilt Derivative

<p>Gravity Satellite has been widely used in tectonic studies and regional of geological mapping. The Satellite Gravity data are provided free by Scripps Institution of Oceanography, University of California San Diego. The data are acquired by GEOSAT and ERS-1 satellites with a 1.5 km resolution for one pixel. For a further application, the tilt derivative analytic technique was used in order to enhance linear trends of the geological structure revealed by the Bouguer anomalies. The method is represented by the value of an angle between the total horizontal and vertical derivative from the gravity data. The results show that the tilt derivative calculation has been able to map clearly some geological structures on the north of Sumatra i.e., the Aceh and the Seulimeuem segments, as well as some local faults around them. On the other hand, Banda Aceh as the capital city of Aceh Province and Pidie District is dominated by positive values of the tilt derivative anomalies. The data coincide with geological maps of both areas where they are covered by alluvial deposits. Based on the result, it can be concluded that the tilt derivative method is potentially used for quick interpretation of the satellite gravity data.</p>

scholarly journals Propagation of Convective Complexes Observed by TRMM in the Eastern Tropical Atlantic

2012 ◽  
Vol 6 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Leonard M. Druyan ◽  
Matthew Fulakeza
Keyword(s):  
West African ◽  
Intertropical Convergence Zone ◽  
Tropical Atlantic ◽  
African Easterly Waves ◽  
Tropical Rainfall Measurement Mission ◽  
Easterly Waves ◽  
Squall Lines ◽  
Latitude Distribution ◽  
Trmm Precipitation ◽  
Synoptic Feature

Precipitation maxima during the West African summer monsoon propagate generally westward in tandem with African easterly waves. A heretofore unreported, repeating pattern of northward drift of precipitation maxima is detected on Tropical Rainfall Measurement Mission (TRMM satellite) time-latitude distributions of daily accumulations over the eastern tropical Atlantic. Corresponding 3-hourly TRMM accumulations show that the northward drifting envelopes of precipitation during August 2006 are often comprised of individual swaths propagating towards the southwest, presumably as mesoscale squall lines. The implied northward drift on the time-latitude distribution is a component of a resultant northwestward movement. The study examines the entire available record of TRMM precipitation observations, 1998-2010, to summarize TRMM maxima propagation over the eastern tropical Atlantic. Meridional displacements of precipitation maxima are most prevalent in June-September 2006, occurring less frequently during other summers. An investigation of geopotential and circulation fields, limited to two case studies, suggests mechanisms to explain some of the observed propagation of TRMM maxima. In one event, northward drift of the precipitation envelope is consistent with the corresponding displacement of the intertropical convergence zone trough, although the southwest propagation of individual mesoscale convection maxima does not correspond to any synoptic feature on reanalysis circulation or reanalysis downscaled by a regional model. One speculation is that southwestward propagation of precipitation maxima could be caused by regeneration of convection at outflow boundaries of mature thunderstorms.

scholarly journals Sequential inversion of GOCE satellite gravity gradient data and terrestrial gravity data for the lithospheric density structure in the North China Craton

Solid Earth ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 1121-1144
Author(s):  
Yu Tian ◽  
Yong Wang
Keyword(s):  
North China ◽  
Gravity Data ◽  
Initial Density ◽  
Gravity Gradient ◽  
Density Structure ◽  
Satellite Gravity ◽  
Density Data ◽  
The North ◽  
Density Anomaly ◽  
Goce Satellite

Abstract. The North China Craton (NCC) is one of the oldest cratons in the world. Currently, the destruction mechanism and geodynamics of the NCC remain controversial. All of the proposed views regarding the issues involve studying the internal density structure of the NCC lithosphere. Gravity field data are among the most important data in regard to investigating the lithospheric density structure, and gravity gradient data and gravity data each possess their own advantages. Given the different observational plane heights between the on-orbit GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) satellite gravity gradient and terrestrial gravity and the effects of the initial density model on the inversion results, sequential inversion of the gravity gradient and gravity are divided into two integrated processes. By using the preconditioned conjugate gradient (PCG) inversion algorithm, the density data are calculated using the preprocessed corrected gravity anomaly data. Then, the newly obtained high-resolution density data are used as the initial density model, which can serve as constraints for the subsequent gravity gradient inversion. Several essential corrections are applied to the four gravity gradient tensors (Txx, Txz, Tyy, Tzz) of the GOCE satellite, after which the corrected gravity gradient anomalies (T′xx, T′xz, T′yy, T′zz) are used as observations. The lithospheric density distribution result within the depth range of 0–180 km in the NCC is obtained. This study clearly illustrates that GOCE data are helpful in understanding the geological settings and tectonic structures in the NCC with regional scale. The inversion results show that in the crust the eastern NCC is affected by lithospheric thinning with obvious local features. In the mantle, the presented obvious negative-density areas are mainly affected by the high-heat-flux environment. In the eastern NCC, the density anomaly in the Bohai Bay area is mostly attributed to the extension of the Tancheng–Lujiang major fault at the eastern boundary. In the western NCC, the crustal density anomaly distribution of the Qilian block is consistent with the northwest–southeast strike of the surface fault belt, whereas such an anomaly distribution experiences a clockwise rotation to a nearly north–south direction upon entering the mantle.

Joint inversion of the lithospheric density struture in the North China Craton based on GOCE satellite gravity gradient data and surface gravity data

2020 ◽  
Author(s):  
Yu Tian ◽  
Yong Wang
Keyword(s):  
North China ◽  
Joint Inversion ◽  
Gravity Data ◽  
Initial Density ◽  
Gravity Gradient ◽  
Density Structure ◽  
Satellite Gravity ◽  
Density Data ◽  
The North ◽  
Goce Satellite

&lt;p&gt;The North China Craton (NCC) is one of the oldest cratons in the world. Currently, the destruction mechanism and geodynamics of the NCC still remain controversial. All of the proposed views regarding the issues involve studying the internal density structure of the NCC lithosphere. Gravity field data are one of the most important data in regard to investigating the lithospheric density structure, the gravity gradient data and the gravity data possess their own advantages. Given the inconsistency of the on orbit GOCE satellite gravity gradient and surface gravity observation plane height, also effects of the initial density model upon of the inversion results, the joint inversion of gravity gradient and gravity are divided into two integrated processes. By using the preconditioned conjugate gradient (PCG) inversion algorithm, the density data are calculated using the preprocessed remaining gravity anomaly data. The newly obtained high resolution density data are then used as the initial density model, which can be served as the constraints for the subsequent gravity gradient inversion. Downward continuation, terrain correction, interface undulation correction and long wavelength correction are performed for the four gravity gradient tensor data(&lt;strong&gt;T&lt;/strong&gt;&lt;sub&gt;xx&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;&lt;sub&gt;xz&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;&lt;sub&gt;yy&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;&lt;sub&gt;zz&lt;/sub&gt;)of the Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite, &amp;#160;after which the remaining gravity gradient anomaly data(&lt;strong&gt;T&lt;/strong&gt;'&lt;sub&gt;xx&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;'&lt;sub&gt;xz&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;'&lt;sub&gt;yy&lt;/sub&gt;&amp;#65292;&lt;strong&gt;T&lt;/strong&gt;'&lt;sub&gt;zz&lt;/sub&gt;) are used as the new observation quantity. Finally, the ultimate lithospheric density distribution within the depth range of 0&amp;#8211;180 km in the NCC is obtained using the same PCG algorithm.&lt;/p&gt;

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