The Assessment of Hydrologic- and Flood-Induced Land Deformation in Data-Sparse Regions Using GRACE/GRACE-FO Data Assimilation

The vertical motion of the Earth’s surface is dominated by the hydrologic cycle on a seasonal scale. Accurate land deformation measurements can provide constructive insight into the regional geophysical process. Although the Global Positioning System (GPS) delivers relatively accurate measurements, GPS networks are not uniformly distributed across the globe, posing a challenge to obtaining accurate deformation information in data-sparse regions, e.g., Central South-East Asia (CSEA). Model simulations and gravity data (from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO)) have been successfully used to improve the spatial coverage. While combining model estimates and GRACE/GRACE-FO data via the GRACE/GRACE-FO data assimilation (DA) framework can potentially improve the accuracy and resolution of deformation estimates, the approach has rarely been considered or investigated thus far. This study assesses the performance of vertical displacement estimates from GRACE/GRACE-FO, the PCRaster Global Water Balance (PCR-GLOBWB) hydrology model, and the GRACE/GRACE-FO DA approach (assimilating GRACE/GRACE-FO into PCR-GLOBWB) in CSEA, where measurements from six GPS sites are available for validation. The results show that GRACE/GRACE-FO, PCR-GLOBWB, and GRACE/GRACE-FO DA accurately capture regional-scale hydrologic- and flood-induced vertical displacements, with the correlation value and RMS reduction relative to GPS measurements up to 0.89 and 53%, respectively. The analyses also confirm the GRACE/GRACE-FO DA’s effectiveness in providing vertical displacement estimates consistent with GRACE/GRACE-FO data while maintaining high-spatial details of the PCR-GLOBWB model, highlighting the benefits of GRACE/GRACE-FO DA in data-sparse regions.

Download Full-text

Pseudo-3D ground deformation map of Sicily derived from Sentinel-1 InSAR time-series

10.5194/egusphere-egu21-7105 ◽

2021 ◽

Author(s):

Maxime Henriquet ◽

Michel Peyret ◽

Stéphane Dominguez ◽

Giovanni Barreca ◽

Jacques Malavieille ◽

...

Keyword(s):

Time Series ◽

Reference Frame ◽

Time Window ◽

Ground Deformation ◽

Regional Scale ◽

Vertical Motion ◽

Transient State ◽

Tectonic Activity ◽

Central Mediterranean ◽

Spatial Coverage

&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Since the Neogene, the Central Mediterranean geodynamics is controlled by the migration of narrow orogenic belts, driven by fast slabs retreat, and the slowly converging Nubian and Eurasian plates. Nowadays, the Calabrian Arc continues its southeast migration in response to the Ionian oceanic plate rollback but at a much slower rate. The Sicilian kinematics has reached a transient state between the ending subduction-collision phase that formed the island, and the steady-state convergence between Africa and Eurasia. This setting explains why Sicily is among the most seismically active region of the Mediterranean, gathering the most destructive historical events recorded in Italy, such as the Noto (1693, Mw &#8764; 7.4) and Messina earthquakes (1908, Mw &#8764; 7.1). Such tectonic activity has led to numerous studies aimed at evaluating current surface motions at a regional scale using GPS networks. To improve the spatial coverage, we built the first 3D geodetic velocity field over the whole Sicily Island by processing from the Sentinel-1 InSAR time-series.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Averaged velocities along the ascending and descending satellite line-of-sight (LOS) were obtained using the Permanent-Scatterer approach (PS-InSAR) over the 2015-2020 period. We converted PS velocity fields into the Nubia reference frame, with the ITRF2014 vertical reference, by adjusting PS to 3D-GPS mean velocities. Reliable GPS velocities were retrieved from time-series of the MAGNET GPS network, leading to about 40selectedsitescoveringSicily and south-west Calabria. Onalltracks, theagreementbetweenPSandGPSLOSvelocitiesisexcellent (rms < 1mm/yr), and derived orbital corrections are robust, except for the western descending track that is only constrained by five GPS data. Since the projected north-south GPS velocity difference along the LOS is about 0.5 mm/yr, we assumed that thenorth-componentoftheground displacementisnegligible. By reducing the problem to a 2D estimation(East and Up component) and using both ascending and descending LOS velocities, we derived the East-andUp-component of the ground deformation within the Nubia-ITRF2014 reference frame. Uncertainties are estimated in the order of 1mm/yr.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; The results show that the Up-component is consistent with previous works indicating a significant uplift of the Peloritani range (~ 1&#177;0.5 mm/yr) in north-eastern Sicily. Together with the East-component, the whole Peloritani block appears, however, as a coherent tectonic unit and does not show any dislocation along the Tindari line, as suggested by previous structural field observations. Interestingly, PS-InSAR data evidence an eastward tilting of the Hyblean Plateau, with about 1.5 mm/yr of subsidence of the Augusta bay relative to the Vittoria plain, and a 1 to 2 mm/yr of differential vertical motion along the southern coast, between Agrigento and the Licata and Sciacca locations. Although the reconstructed ground motion only captures a short time-window of the seismic cycle, these data represent a major milestone to evaluate the seismic hazard of Sicily.

Download Full-text

The Comparison of Land Subsidence between East and West Side of Bangkok, Thailand

Built Environment Journal ◽

10.24191/bej.v17isi.11740 ◽

2020 ◽

Vol 17 (3) ◽

pp. 1

Author(s):

Angkana Pumpuang ◽

Anuphao Aobpaet

Keyword(s):

Time Series ◽

Land Subsidence ◽

Time Series Data ◽

Series Data ◽

Industrial Estates ◽

Vertical Displacements ◽

Land Deformation ◽

Extensive Farming ◽

Chao Phraya River ◽

Set Up

The land deformation in line of sight (LOS) direction can be measured using time series InSAR. InSAR can successfully measure land subsidence based on LOS in many big cities, including the eastern and western regions of Bangkok which is separated by Chao Phraya River. There are differences in prosperity between both sides due to human activities, land use, and land cover. This study focuses on the land subsidence difference between the western and eastern regions of Bangkok and the most possible cause affecting the land subsidence rates. The Radarsat-2 single look complex (SLC) was used to set up the time series data for long term monitoring. To generate interferograms, StaMPS for Time Series InSAR processing was applied by using the PSI algorithm in DORIS software. It was found that the subsidence was more to the eastern regions of Bangkok where the vertical displacements were +0.461 millimetres and -0.919 millimetres on the western and the eastern side respectively. The districts of Nong Chok, Lat Krabang, and Khlong Samwa have the most extensive farming area in eastern Bangkok. Besides, there were also three major industrial estates located in eastern Bangkok like Lat Krabang, Anya Thani and Bang Chan Industrial Estate. By the assumption of water demand, there were forty-eight wells and three wells found in the eastern and western part respectively. The number of groundwater wells shows that eastern Bangkok has the demand for water over the west, and the pumping of groundwater is a significant factor that causes land subsidence in the area.Keywords: Subsidence, InSAR, Radarsat-2, Bangkok

Download Full-text

The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements

Sensors ◽

10.3390/s21144842 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4842

Author(s):

Waldemar Kamiński

Keyword(s):

Accuracy Assessment ◽

Theoretical Models ◽

Vertical Displacement ◽

Serial Connection ◽

Vertical Displacements ◽

Comprehensive Determination ◽

The One ◽

The Individual ◽

Reference Sensor

Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

Download Full-text

Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

Remote Sensing ◽

10.3390/rs13050874 ◽

2021 ◽

Vol 13 (5) ◽

pp. 874

Author(s):

Yu Chen ◽

Mohamed Ahmed ◽

Natthachet Tangdamrongsub ◽

Dorina Murgulet

Keyword(s):

Land Surface ◽

Large Scale ◽

Surface Deformation ◽

Vertical Displacement ◽

Nile River ◽

Reservoir Volume ◽

Novel Approach ◽

Land Deformation ◽

Large Scale Land ◽

The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

Download Full-text

Concurrence of 1- and 3-Min Sit-to-Stand Tests with the 6-Min Walk Test in Idiopathic Pulmonary Fibrosis

Respiration ◽

10.1159/000515335 ◽

2021 ◽

pp. 1-9

Author(s):

Arnaud Fedi ◽

Sophia Keddache ◽

Sébastien Quétant ◽

Alicia Guillien ◽

Anestis Antoniadis ◽

...

Keyword(s):

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Daily Practice ◽

Vertical Displacement ◽

Physiological Parameters ◽

Walk Test ◽

Prognostic Information ◽

Exercise Tests ◽

Sit To Stand ◽

Vertical Displacements

Background: In idiopathic pulmonary fibrosis (IPF), some physiological parameters measured during a 6-min walk test (6-MWT) impart reliable prognostic information. Sit-to-stand tests (STSTs) are field exercise tests that are easier to implement than the 6-MWT in daily practice. Objectives: The aims of the study were to test the reproducibility and compare 2 STSTs (the 1-min STST [1-STST] and the semi-paced 3-min chair rise test [3-CRT]) in IPF, and to determine if selected physiological parameters (speed of displacement and changes in pulse oxygen saturation [SpO2]) are interchangeable between the STSTs and the 6-MWT. Methods: Thirty-three patients with stable IPF were studied in 3 French expert centers. To test reproducibility, intra-class correlations (ICCs) of parameters measured during tests performed 7–14 days apart were calculated. To test interchangeability, the agreement and correlation of physiological responses measured during STSTs and during 6-MWT were studied. Results: Vertical displacements and changes in SpO2 during both STSTs were reproducible, with ICCs ranging from 0.78 [0.63–0.87] to 0.95 [0.92–0.97]. Vertical displacements during 1-STST and 3-CRT were correlated with 6-MWT distance (correlation coefficients (r) of 0.72 and 0.77, respectively; p < 0.001). Similarly, correlations were found between changes in SpO2 measured during the 2 STSTs and the 6-MWT, with coefficients ranging from 0.73 to 0.91 (p < 0.001). Distance walked and SpO2 during 6-MWT were well estimated from vertical displacement and SpO2 during the 2 STSTs, respectively. Conclusion: The correlations found between the 2 STSTs and the 6-MWT suggest that STSTs may be of interest to assess displacement and exercise-induced changes in SpO2 in IPF patients.

Download Full-text

Seismic Activity of the Manisa Fault Zone in Western Turkey Constrained by Cosmogenic 36Cl Dating

Geosciences ◽

10.3390/geosciences11110451 ◽

2021 ◽

Vol 11 (11) ◽

pp. 451

Author(s):

Nasim Mozafari ◽

Çağlar Özkaymak ◽

Dmitry Tikhomirov ◽

Susan Ivy-Ochs ◽

Vasily Alfimov ◽

...

Keyword(s):

Fault Zone ◽

Normal Fault ◽

Vertical Displacement ◽

Historical Records ◽

Western Turkey ◽

Slip Rates ◽

Vertical Displacements ◽

Surface Ruptures ◽

Fault Scarps ◽

Calculated Average

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.

Download Full-text

Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type

Artificial Satellites ◽

10.2478/arsa-2020-0008 ◽

2020 ◽

Vol 55 (3) ◽

pp. 100-117

Author(s):

Viktor Szabó ◽

Dorota Marjańska

Keyword(s):

Gravity Field ◽

Ocean Circulation ◽

Gravity Data ◽

The Other ◽

Subsurface Water ◽

Satellite Gravity ◽

Absolute Gravimetry ◽

The Earth ◽

Gravity Measurements ◽

Gravity Recovery

AbstractGlobal satellite gravity measurements provide unique information regarding gravity field distribution and its variability on the Earth. The main cause of gravity changes is the mass transportation within the Earth, appearing as, e.g. dynamic fluctuations in hydrology, glaciology, oceanology, meteorology and the lithosphere. This phenomenon has become more comprehensible thanks to the dedicated gravimetric missions such as Gravity Recovery and Climate Experiment (GRACE), Challenging Minisatellite Payload (CHAMP) and Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). From among these missions, GRACE seems to be the most dominating source of gravity data, sharing a unique set of observations from over 15 years. The results of this experiment are often of interest to geodesists and geophysicists due to its high compatibility with the other methods of gravity measurements, especially absolute gravimetry. Direct validation of gravity field solutions is crucial as it can provide conclusions concerning forecasts of subsurface water changes. The aim of this work is to present the issue of selection of filtration parameters for monthly gravity field solutions in RL06 and RL05 releases and then to compare them to a time series of absolute gravimetric data conducted in quasi-monthly measurements in Astro-Geodetic Observatory in Józefosław (Poland). The other purpose of this study is to estimate the accuracy of GRACE temporal solutions in comparison with absolute terrestrial gravimetry data and making an attempt to indicate the significance of differences between solutions using various types of filtration (DDK, Gaussian) from selected research centres.

Download Full-text

Pan tropical biomass equations for Mexico's dry forests

Agronomía Colombiana ◽

10.15446/agron.colomb.v32n3.45627 ◽

2014 ◽

Vol 32 (3) ◽

pp. 367-376 ◽

Cited By ~ 1

Author(s):

José Návar

Keyword(s):

Specific Gravity ◽

Stand Structure ◽

Gravity Data ◽

Theoretical Models ◽

Tropical Dry Forests ◽

Large Sample Size ◽

Dry Forests ◽

Wood Specific Gravity ◽

Spatial Coverage ◽

Ecological Importance

This study reports a set of robust regional M-tree allometric equations for Mexico's tropical dry forests and their application to a forest inventory dataset for the States of Durango and Sinaloa, Mexico. Calculated M data from 15 reported equations were fitted, applied and validated for regional and global models. Proposed theoretical models, empirically derived equations, as well as global and local reported equations were fitted and applied to calculated M-tree data using wood specific gravity, diameter at breast height, and top height as exogenous variables. Empirically-derived, computer-based equations assessed the M-tree evaluations slightly better than the theoretical, the global and the local models. However, the theoretical models projected compatible M-tree values and deserve further attention once wood specific gravity data are collected in the field. Using the best fit equation, mean M plot density values of 30, 41 and 35 Mg ha-1 were estimated from 57 plots (1,600 m2 each), 217 plots (1,000 m2 each) and 166 plots (1,000 m2 each) in the tropical dry forests of the States of Durango, Tiniaquis and Vado Hondo (Sinaloa), respectively. The large sample size, the richness of the tested allometric models, the economic and ecological importance of this data-source, and the spatial coverage of these equations made this dataset uniquely useful for biomass, charcoal, and other bio-energy estimations, as well as for understanding the inherent heterogeneity of the stand-structure in dynamic tropical forest environments.

Download Full-text

Dry and moist dynamics shape regional patterns of extreme precipitation sensitivity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1913584117 ◽

2020 ◽

Vol 117 (16) ◽

pp. 8757-8763 ◽

Cited By ~ 1

Author(s):

Ji Nie ◽

Panxi Dai ◽

Adam H. Sobel

Keyword(s):

Global Warming ◽

Extreme Precipitation ◽

Large Scale ◽

Climate Model ◽

Regional Scale ◽

Vertical Motion ◽

Precipitable Water ◽

Small Scale ◽

Climate Projections ◽

Regional Patterns

Responses of extreme precipitation to global warming are of great importance to society and ecosystems. Although observations and climate projections indicate a general intensification of extreme precipitation with warming on global scale, there are significant variations on the regional scale, mainly due to changes in the vertical motion associated with extreme precipitation. Here, we apply quasigeostrophic diagnostics on climate-model simulations to understand the changes in vertical motion, quantifying the roles of dry (large-scale adiabatic flow) and moist (small-scale convection) dynamics in shaping the regional patterns of extreme precipitation sensitivity (EPS). The dry component weakens in the subtropics but strengthens in the middle and high latitudes; the moist component accounts for the positive centers of EPS in the low latitudes and also contributes to the negative centers in the subtropics. A theoretical model depicts a nonlinear relationship between the diabatic heating feedback (α) and precipitable water, indicating high sensitivity of α (thus, EPS) over climatological moist regions. The model also captures the change of α due to competing effects of increases in precipitable water and dry static stability under global warming. Thus, the dry/moist decomposition provides a quantitive and intuitive explanation of the main regional features of EPS.

Download Full-text

The spectrum of GPS measurement errors and the accuracy of airborne gravity measurements

Geophysics ◽

10.1190/1.1442922 ◽

1990 ◽

Vol 55 (8) ◽

pp. 1101-1104 ◽

Cited By ~ 4

Author(s):

D. R. Bower ◽

J. Kouba ◽

R. J. Beach

Keyword(s):

Measurement Errors ◽

Regional Scale ◽

Vertical Motion ◽

Airborne Gravity ◽

Width Ratio ◽

Noise Power ◽

Power Spectral ◽

Gps Measurement ◽

Gravity Measurements ◽

Allowable Error

Recent observations (Georgiadou and Kleusberg, 1987; Kleusberg et al., 1989) suggest that errors in GPS carrier phase observations at frequencies within the gravity passband of airborne gravity systems may be due mainly to multipath interference. Further, the power spectral density (PSD) of these errors has been found to fall off rapidly with increase in frequency throughout the anticipated gravity passband, in the manner of a red spectrum rather than a white (which remains constant). It is shown that this implies a much greater allowable error in GPS‐derived altitude reference than would be the case if the PSD of altitude errors (1) was white, (2) had the same shape as that of typical aircraft vertical motion, or (3) was dominated by a sinusoidal wave located near the high frequency limit of the gravity passband. This enhances the feasibility of airborne gravity for regional scale surveys and perhaps explains why actual measurements have been better than predicted. For example, given a uniform [Formula: see text] distribution of spectral noise power and a speed to grid‐width ratio of 60 per hour, an rms altitude error as large as 12 cm will still allow the computation of acceleration correction with an accuracy of 2 mGal. For the same conditions, the allowable rms altitude error given a white distribution of spectral noise power is 1.5 cm.

Download Full-text