Seasonal Mass Changes and Crustal Vertical Deformations Constrained by GPS and GRACE in Northeastern Tibet

Pan, Yuanjin; Shen, Wen Bin; Hwang, Cheinway; Liao, Chaoming; Zhang, Tengxu; Zhang, Guoqing

doi:10.3390/s16081211

Cited by 28 publications

(16 citation statements)

References 51 publications

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“…Several recent studies have compared the mass loading signals recorded by GPS and GRACE‐derived displacement (GDD) time series, showing potential for joint interpretation of the two data sets, but all of these studies also reported statistically significant discrepancies. Many of these studies chose regions to perform comparisons with a large loading signal, such as the Amazon basin (Davis et al, ; Fu et al, ; Moreira et al, ), southeast Asia (Fu et al, ; Steckler et al, ), the Nepal Himalaya (Fu & Freymueller, ), southern Alaska (Fu et al, ), West Africa (Nahmani et al, ), Tibet (Pan et al, ), and Greenland (Bevis et al, ). Some studies have also compared GPS and GDD in locations with less extreme loading fluctuations (Gu et al, ; Tregoning et al, ).…”

Section: Introductionmentioning

confidence: 99%

Vertical Displacements of the Amazon Basin From GRACE and GPS

2020

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The extent to which Gravity Recovery and Climate Experiment (GRACE)‐recovered gravity anomalies can improve our understanding of Global Positioning System (GPS)‐measured vertical displacements is currently uncertain. To address this issue, we compared vertical displacements measured by 23 GPS stations in the Amazon basin with displacements estimated from GRACE geopotential fields. We show that despite poor correlation ( r2=0.15) between rate estimates in GPS and GRACE‐derived displacement time series, further analyses reveal low bias between annual amplitude estimates and a scaling near 1. There is higher correlation ( r2=0.78) between annual periodic motions, with near 1 to 1 agreement, but there is poor correlation ( r2=0.02) and little agreement between semiannual amplitude estimates. Subtracting GRACE displacements from the GPS time series flattens the GPS power spectra, reducing the spectral index magnitude, on average, from −1.2759±0.0007 (“fractional Brownian motion”) to −0.3346±0.0006 (“fractional Gaussian noise”), suggesting that some fraction of the apparent GPS error correlation derives from mass loading signals that are not completely characterized by secular trends or seasonal periodic motions. From March 2011 to November 2016, we find a GPS and GRACE‐derived displacement combined average uplift of the Amazon basin of 1.20±0.26 mm/yr and combined average annual periodic motion of 10.22±0.57 mm. Deviations from a standard trajectory model for site motion are apparent in both data sets and appear to coincide with various flooding and drought events between 2011 and 2016, which suggests that the GPS coordinate time series record displacements driven by large‐scale climate oscillations.

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Section: Introductionmentioning

confidence: 99%

Vertical Displacements of the Amazon Basin From GRACE and GPS

2020

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“…Thus, the Gravity Recovery and Climate Experiment (GRACE) and the combined loading models (CLMs)-a combination of nontidal atmosphere and ocean loadings and continental water storage loading-have become suitable datasets for modeling VCDs induced by the different surface mass variations. Several studies have been conducted in areas with strong hydrological signals using GRACE and GPS techniques to determine VCDs (see, e.g., Chanard et al 2014;Tiwari et al 2014;Pan et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Determining seasonal displacements of Earth’s crust in South America using observations from space-borne geodetic sensors and surface-loading models

Ferreira

Castro

Ndehedehe

et al. 2019

Earth Planets Space

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There are small pieces of evidence, suggesting that South America's hydrological cycle is changing, which impacts its water availability and, consequently, the Earth's surface due to its elastic response to the surface mass loading/ unloading. Therefore, we analyzed 3 to 15 years of vertical crustal displacements (VCDs) due to mass loadings using 292 Global Positioning System (GPS) stations in South America, which are essential for studies related to tectonic phenomena, for example. Thus, we investigated whether the intra-annual variabilities of the displacements could be reduced using modeled VCDs and inverted displacements from Gravity Recovery and Climate Experiment (GRACE) harmonic solutions (Release 06). The modeled VCDs come from the combination of nontidal atmospheric and ocean loadings with the hydrological loadings from the land-surface model (GLDAS) and reanalysis (MERRA). We found that the highest amplitudes of VCDs of the annual signals are concentrated mainly over the Amazon Rainforest and Brazilian Highlands. However, the results also show different behavior throughout other physiographic provinces of South America, which shows low water capabilities as "sensed" by GRACE and described by the GLDAS and MERRA models. Accordingly, when we disregard the stations over the Andes Mountains and Patagonia in the analysis, the highest reduction in the variability of GPS-observed VCDs is achieved while using GRACE (79% of the sites), MERRA (75% of the sites), and GLDAS (74% of the sites). For these stations, the amplitudes (and phases) of the annual signals depicted by the geodetic sensors generally agree, while those from GLDAS and MERRA explain only approximately 50% of the deformation. However, in the southwest region of South America (between the latitude bands of − 40° to − 30°), GPS annual signals, which reached up to 11 mm, are much larger than those from GRACE and the models due to the existence of lakes that are not resolved in global analysis. These inconsistencies between GPS-observed VCDs and those derived from GRACE and the other models require further investigation, specifically for Chile.

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“…Meanwhile, the vertical crustal deformation throughout Tibet at different spatial and temporal scales (e.g. surface short-term and long-term crustal deformation) brings us new insights on the dynamics of contemporary tectonic processes202122232425. However, how the crustal three-dimensional (3D) deformation varies and the dynamics mechanism of underlying material changes in and around Tibet remains controversy81418.…”

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confidence: 99%

Contemporary crustal movement of southeastern Tibet: Constraints from dense GPS measurements

Pan

Shen

2017

Sci Rep

Self Cite

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The ongoing collision between the Indian plate and the Eurasian plate brings up N-S crustal shortening and thickening of the Tibet Plateau, but its dynamic mechanisms remain controversial yet. As one of the most tectonically active regions of the world, South-Eastern Tibet (SET) has been greatly paid attention to by many geoscientists. Here we present the latest three-dimensional GPS velocity field to constrain the present-day tectonic process of SET, which may highlight the complex vertical crustal deformation. Improved data processing strategies are adopted to enhance the strain patterns throughout SET. The crustal uplifting and subsidence are dominated by regional deep tectonic dynamic processes. Results show that the Gongga Shan is uplifting with 1–1.5 mm/yr. Nevertheless, an anomalous crustal uplifting of ~8.7 mm/yr and negative horizontal dilation rates of 40–50 nstrain/yr throughout the Longmenshan structure reveal that this structure is caused by the intracontinental subduction of the Yangtze Craton. The Xianshuihe-Xiaojiang fault is a major active sinistral strike-slip fault which strikes essentially and consistently with the maximum shear strain rates. These observations suggest that the upper crustal deformation is closely related with the regulation and coupling of deep material.

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Seasonal Mass Changes and Crustal Vertical Deformations Constrained by GPS and GRACE in Northeastern Tibet

Cited by 28 publications

References 51 publications

Vertical Displacements of the Amazon Basin From GRACE and GPS

Vertical Displacements of the Amazon Basin From GRACE and GPS

Determining seasonal displacements of Earth’s crust in South America using observations from space-borne geodetic sensors and surface-loading models

Contemporary crustal movement of southeastern Tibet: Constraints from dense GPS measurements

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