scholarly journals Tracking the weight of Hurricane Harvey’s stormwater using GPS data

2018 ◽  
Vol 4 (9) ◽  
pp. eaau2477 ◽  
Author(s):  
Chris Milliner ◽  
Kathryn Materna ◽  
Roland Bürgmann ◽  
Yuning Fu ◽  
Angelyn W. Moore ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Gulf Coast ◽  
Water Storage ◽  
Extreme Precipitation Events ◽  
Global Positioning ◽  
Terrestrial Water ◽  
Elastic Loading ◽  
Gps Networks ◽  
Daily Changes ◽  
Precipitation Events

On 26 August 2017, Hurricane Harvey struck the Gulf Coast as a category four cyclone depositing ~95 km3 of water, making it the wettest cyclone in U.S. history. Water left in Harvey’s wake should cause elastic loading and subsidence of Earth’s crust, and uplift as it drains into the ocean and evaporates. To track daily changes of transient water storage, we use Global Positioning System (GPS) measurements, finding a clear migration of subsidence (up to 21 mm) and horizontal motion (up to 4 mm) across the Gulf Coast, followed by gradual uplift over a 5-week period. Inversion of these data shows that a third of Harvey’s total stormwater was captured on land (25.7 ± 3.0 km3), indicating that the rest drained rapidly into the ocean at a rate of 8.2 km3/day, with the remaining stored water gradually lost over the following 5 weeks at ~1 km3/day, primarily by evapotranspiration. These results indicate that GPS networks can remotely track the spatial extent and daily evolution of terrestrial water storage following transient, extreme precipitation events, with implications for improving operational flood forecasts and understanding the response of drainage systems to large influxes of water.

scholarly journals Akaike’s Bayesian Information Criterion for the Joint Inversion of Terrestrial Water Storage Using GPS Vertical Displacements, GRACE and GLDAS in Southwest China

Entropy ◽  
2019 ◽  
Vol 21 (7) ◽  
pp. 664 ◽  
Author(s):  
Liu ◽  
Fok ◽  
Tenzer ◽  
Chen ◽  
Chen
Keyword(s):  
Bayesian Information Criterion ◽  
Joint Inversion ◽  
Water Storage ◽  
Information Criterion ◽  
Vertical Displacement ◽  
Global Navigation Satellite Systems ◽  
Terrestrial Water Storage ◽  
Satellite Systems ◽  
Terrestrial Water ◽  
Elastic Loading

Global navigation satellite systems (GNSS) techniques, such as GPS, can be used to accurately record vertical crustal movements induced by seasonal terrestrial water storage (TWS) variations. Conversely, the TWS data could be inverted from GPS-observed vertical displacement based on the well-known elastic loading theory through the Tikhonov regularization (TR) or the Helmert variance component estimation (HVCE). To complement a potential non-uniform spatial distribution of GPS sites and to improve the quality of inversion procedure, herein we proposed in this study a novel approach for the TWS inversion by jointly supplementing GPS vertical crustal displacements with minimum usage of external TWS-derived displacements serving as pseudo GPS sites, such as from satellite gravimetry (e.g., Gravity Recovery and Climate Experiment, GRACE) or from hydrological models (e.g., Global Land Data Assimilation System, GLDAS), to constrain the inversion. In addition, Akaike’s Bayesian Information Criterion (ABIC) was employed during the inversion, while comparing with TR and HVCE to demonstrate the feasibility of our approach. Despite the deterioration of the model fitness, our results revealed that the introduction of GRACE or GLDAS data as constraints during the joint inversion effectively reduced the uncertainty and bias by 42% and 41% on average, respectively, with significant improvements in the spatial boundary of our study area. In general, the ABIC with GRACE or GLDAS data constraints displayed an optimal performance in terms of model fitness and inversion performance, compared to those of other GPS-inferred TWS methodologies reported in published studies.

scholarly journals Evaluation of NASA’s MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

2016 ◽  
Vol 17 (2) ◽  
pp. 693-711 ◽  
Author(s):  
Hamed Ashouri ◽  
Soroosh Sorooshian ◽  
Kuo-Lin Hsu ◽  
Michael G. Bosilovich ◽  
Jaechoul Lee ◽  
...  
Keyword(s):  
United States ◽  
Extreme Precipitation ◽  
Gulf Coast ◽  
The United States ◽  
Value Theory ◽  
Extreme Value ◽  
Precipitation Extremes ◽  
Precipitation Product ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract This study evaluates the performance of NASA’s Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979–2010. The Climate Prediction Center (CPC) U.S. Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scale patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRA tends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1) MERRA shows a spurious negative trend in Nebraska and Kansas, which is most likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over the Gulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates that the hurricane and winter seasons are contributing the most to these trend patterns in the southeastern United States. In addition, the increasing annual trend simulated by MERRA in the Gulf Coast region is due to an incorrect trend in winter precipitation extremes.

scholarly journals Optimal observational planning of local GPS networks: assessing an analytical method

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
H. Mehrabi ◽  
B. Voosoghi
Keyword(s):  
Global Positioning System ◽  
Analytical Method ◽  
Cost Reduction ◽  
Operational Research ◽  
Field Work ◽  
Programming Algorithm ◽  
Positioning System ◽  
Global Positioning ◽  
Gps Networks ◽  
Selection Of

AbstractPrecision, reliability and cost are the major criteria applied in optimization and design of geodetic networks. The terrestrial networks are being replaced quickly by permanent and campaign Global Positioning System (GPS) networks. These networks must be optimized using the same three criteria. In this article the optimization of the observational plan of local GPS networks (Second Order Design (SOD)) is considered using the precision criterion. This study is limited to the selection of optimal numbers and the best distribution of the non-trivial baselines throughout the network. This objective is accomplished based on the SOD solution through the analytical method in operational research by the means of quadratic programming algorithm. This presented method is tested on a real GPS network and appears to be a useful technique in terms of cost reduction in the field work by the provided observational plan and optimal distribution of the baselines throughout the network. Results indicate that weights of almost 36% of the baselines are negligiblewhen compared to the weights of the rest of the baselines; therefore, they could be eliminated fromthe observational plan, resulting in a 36% saving in the fieldwork cost.

Comparison of Coseismic Displacement Obtained from GEONET and Seismic Networks

2016 ◽  
Vol 10 (02) ◽  
pp. 1640002 ◽  
Author(s):  
Luis Moya ◽  
Fumio Yamazaki ◽  
Wen Liu
Keyword(s):  
Global Positioning System ◽  
Strong Motion ◽  
Search Method ◽  
Baseline Correction ◽  
Positioning System ◽  
Coseismic Displacement ◽  
Strong Motion Station ◽  
Global Positioning ◽  
Gps Networks ◽  
Seismic Networks

It is generally recognized that permanent displacements estimated by the double integration of acceleration records need a suitable baseline correction. Current baseline correction methods have been validated by comparing the displacements with those from the Global Positioning System (GPS) records nearby, but GPS stations that are sufficiently close to a strong-motion station are scarce. Because the [Formula: see text] Tohoku-Oki earthquake produced geodetic displacements in a wide area and because dense strong-motion and GPS networks are available in Japan, we interpolated the displacements calculated from GPS records to estimate the permanent displacements at 508 strong-motion stations. The estimated results were used to evaluate uncertainties in permanent displacements obtained using two baseline correction methods, and results were found to be reliable only for KiK-net’s borehole acceleration records. A new joint parameter search method for the surface and borehole records was further proposed, and reliable results were obtained for KiK-net’s surface records.

Surface deformations observed by GPS and its relation to groundwater variations in France

2021 ◽  
Author(s):  
Anita Thea Saraswati ◽  
Kuei-Hua Hsu ◽  
Tonie van Dam ◽  
Annette Eicker
Keyword(s):  
Surface Deformation ◽  
Water Storage ◽  
Groundwater Depletion ◽  
Surface Displacements ◽  
Global Positioning ◽  
Terrestrial Water ◽  
Lakes And Reservoirs ◽  
Surface Water Storage ◽  
Global Hydrology

<p>The Global Positioning System (GPS) measures surface displacements in response to time-varying terrestrial water mass variations. Components of surface water storage include water in lakes and reservoirs, snow, and soil moisture. Groundwater depletion or recharge will also contribute to the overall water storage. Understanding the nature of the observed GPS displacements related to the continental water variations is important to help identify which compartment in the total water storage controls the water changes in any particular region. In this study, we demonstrate the potential of GPS to observe the surface displacements induced by groundwater variations in France. In-situ groundwater observations from boreholes in France are used to be compared with GPS displacements. Groundwater data are processed to obtain the Equivalent Water Height (EWH) and used to forward model surface deformation. Displacements predicted using EWH variations from the WaterGAP Global Hydrology Model (WGHM) will also be compared to the GPS displacements.</p>

scholarly journals A Robust Strategy for Ambiguity Resolution Using Un-Differenced and Un-Combined GNSS Models in Network RTK

2015 ◽  
Vol 69 (3) ◽  
pp. 504-520
Author(s):  
Denghui Wang ◽  
Chengfa Gao ◽  
Shuguo Pan ◽  
Yang Yang
Keyword(s):  
Global Positioning System ◽  
Ambiguity Resolution ◽  
Plate Boundary ◽  
Double Difference ◽  
Fixed Rate ◽  
Long Baseline ◽  
Global Positioning ◽  
Baseline Solution ◽  
Integrated Processing ◽  
Gps Networks

An increasing number of reference stations have been established, leading to a sharp increase in the workload of Double-Difference (DD) baseline solutions, which are not appropriate for the integrated processing of denser networks. Correlations among the ambiguities in DD models are complex, and it is difficult to get precise solutions. This paper improves the DD ambiguity resolution performance over a long baseline, using a modified strategy based on an Un-Differenced (UD) and Un-Combined (UC) model. The satellite clocks are estimated as parameters, which are properly constrained by real-time satellite clock products for improving the smoothness of ambiguities. We use data from the Earth Scope Plate Boundary Observatory to examine the presented method in Global Positioning System (GPS) networks. Our method obtained more obviously centralised distributions. The successful fixed rate was 96·4% for the DD baseline solution, and 98·4% for the UD method. The proposed strategy is appropriate for the distributed architecture of extensive systems and avoids a heavy computational burden.

IDENTIFICATION OF THE SPATIAL POSITION OF PERMANENT GPS STATIONS IN THE BALTIC REGION

Aviation ◽  
2012 ◽  
Vol 16 (2) ◽  
pp. 38-41
Author(s):  
Daiva Levinskaitė
Keyword(s):  
Global Positioning System ◽  
Repeated Measurements ◽  
Spatial Position ◽  
Earth’S Crust ◽  
Use Of Data ◽  
Global Positioning ◽  
Spatial Coordinates ◽  
Gps Networks ◽  
Earth's Crust ◽  
The Baltic

Since the last decade of the 20th century, data on repeated measurements from the Global Positioning System (hereinafter referred to as GPS) have been commonly used globally to investigate the motion of the Earth's crust. With the use of data on repeated measurements in GPS networks (coordinates of GPS network stations, lengths of spans between the GPS stations or other changes of elements), it is possible to detect horizontal motions of the Earth crust that take place in the period between repeated measurements. The most elementary way of detecting the motions of the Earth's crust is a comparison of the coordinates of identical stations of geodetic networks found on geodetic measurements carried out at different moments. The object of this research is the identification of the spatial position of permanent GPS stations, i.e. changes in spatial coordinates within a certain period.

Unanticipated Uses of the Global Positioning System

2019 ◽  
Vol 47 (1) ◽  
pp. 19-40 ◽  
Author(s):  
Kristine M. Larson
Keyword(s):  
Soil Moisture ◽  
Global Positioning System ◽  
Snow Depth ◽  
Volcanic Eruptions ◽  
Gps Data ◽  
Positioning System ◽  
Vegetation Water Content ◽  
Global Positioning ◽  
Gps Networks ◽  
Vegetation Water

Global Positioning System (GPS) instruments are routinely used today to measure crustal deformation signals from tectonic plate motions, faulting, and glacial isostatic adjustment. In parallel with the expansion of GPS networks around the world, several new and unexpected applications of GPS have been developed. For example, GPS instruments are now being used routinely to measure ground motions during large earthquakes. Access to real-time GPS data streams has led to the development of better hazard warnings for tsunamis, flash floods, earthquakes, and volcanic eruptions. Terrestrial water storage changes can be derived from GPS vertical coordinate time series. Finally, GPS signals that reflect on the surfaces below a GPS antenna can be used to measure soil moisture, snow accumulation, vegetation water content, and water levels. In the future, combining GPS with the signals from the Russian, European, and Chinese navigation constellations will significantly enhance these applications. ▪ GPS data are now routinely used to study the dynamics of earthquake rupture. ▪ GPS instruments are an integral part of warning systems for earth- quakes, tsunamis, flash floods, and volcanic eruptions. ▪ Reflected GPS signals provide a new source of soil moisture, snow depth, vegetation water content, and tide gauge data. ▪ GPS networks can sense changes in soil moisture, groundwater, and snow depth and thus can contribute to water resource assessments.

scholarly journals Synoptic-Scale Characteristics and Precursors of Cool-Season Precipitation Events at St. John’s, Newfoundland, 1979–2005

2009 ◽  
Vol 24 (3) ◽  
pp. 667-689 ◽  
Author(s):  
Shawn M. Milrad ◽  
Eyad H. Atallah ◽  
John R. Gyakum
Keyword(s):  
United States ◽  
Extreme Events ◽  
Gulf Coast ◽  
Precipitable Water ◽  
Geostrophic Wind ◽  
The United States ◽  
Cool Season ◽  
South Central ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract The issue of quantitative precipitation forecasting continues to be a significant challenge in operational forecasting, particularly in regions susceptible to frequent and extreme precipitation events. St. John’s, Newfoundland, Canada, is one location affected frequently by such events, particularly in the cool season (October–April). These events can include flooding rains, paralyzing snowfall, and damaging winds. A precipitation climatology is developed at St. John’s for 1979–2005, based on discrete precipitation events occurring over a time period of up to 48 h. Threshold amounts for three categories of precipitation events (extreme, moderate, and light) are statistically derived and utilized to categorize such events. Anomaly plots of sea level pressure (SLP), 500-hPa height, and precipitable water are produced for up to 3 days prior to the event. Results show that extreme events originate along the Gulf Coast of the United States, with the location of anomaly origin being farther to the north and west for consecutively weaker events, culminating in light events that originate from the upper Midwest of the United States and south-central Canada. In addition, upper-level precursor features are identified up to 3 days prior to the events and are mainly located over the west coast of North America. Finally, results of a wind climatology produced for St. John’s depict a gradual shift in the predominant wind direction (from easterly to southwesterly) of both the 925-hPa geostrophic wind and 10-m observed wind from extreme to light events, inclusively. In addition, extreme events are characterized by almost exclusively easterly winds.

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