Geodesy in the 21st Century

Wdowinski, S.; Eriksson, S. C.

doi:10.1029/2009eo180001

Cited by 9 publications

(9 citation statements)

References 1 publication

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“…During the beginning of the 1990s, geophysicists and geodesists have made it possible to retrieve the amount of WV in the troposphere, by developing methods for measuring the degree to which signals, emitted from global navigation satellite systems (GNSS) and propagates to global positioning systems (GPS) base station receivers, are delayed by atmospheric WV molecules [12]. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) that is retrieved by stochastic filtering of the GPS raw measurements [2,3,13].…”

Section: Introductionmentioning

confidence: 99%

On the Potential of Improving WRF Model Forecasts by Assimilation of High-Resolution GPS-Derived Water-Vapor Maps Augmented with METEOSAT-11 Data

2020

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Improving the accuracy of numerical weather predictions remains a challenging task. The absence of sufficiently detailed temporal and spatial real-time in-situ measurements poses a critical gap regarding the proper representation of atmospheric moisture fields, such as water vapor distribution, which are highly imperative for improving weather predictions accuracy. The estimated amount of the total vertically integrated water vapor (IWV), which can be derived from the attenuation of global positioning systems (GPS) signals, can support various atmospheric models at global, regional, and local scales. Currently, several existing atmospheric numerical models can estimate the IWV amount. However, they do not provide accurate results compared with in-situ measurements such as radiosondes. Here, we present a new strategy for assimilating 2D IWV regional maps estimations, derived from combined GPS and METEOSAT satellite imagery data, to improve Weather Research and Forecast (WRF) model predictions accuracy in Israel and surrounding areas. As opposed to previous studies, which used point measurements of IWV in the assimilation procedure, in the current study, we assimilate quasi-continuous 2D GPS IWV maps, combined with METEOSAT-11 data. Using the suggested methodology, our results indicate an improvement of more than 30% in the root mean square error (RMSE) of WRF forecasts after assimilation relative standalone WRF, when both are compared to the radiosonde measured data near the Mediterranean coast. Moreover, significant improvements along the Jordan Rift Valley and Dead Sea Valley areas are obtained when compared to 2D IWV regional maps estimations. Improvements in these areas suggest the impact of the assimilated high resolution IWV maps, with initialization times which coincide with the Mediterranean Sea Breeze propagation from the coastline to highland stations, as the distance to the Mediterranean Sea shore, along with other features, dictates its arrival times.

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Section: Introductionmentioning

confidence: 99%

On the Potential of Improving WRF Model Forecasts by Assimilation of High-Resolution GPS-Derived Water-Vapor Maps Augmented with METEOSAT-11 Data

2020

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“…In situ tracers such as chemical compounds or isotopes used to track flow paths are also process-based approaches useful for assessing hydrological connectivity across various scales (Ala-aho et al, 2018;Golden et al, 2017;Mcdonnell & Beven, 2014). Despite these former calls to the importance of hydrological connectivity for the assessment of wetland functions (Ponette-González et al, 2014;Pringle, 2001;Hiatt & Passalacqua, 2015;Thorslund et al, 2017), it is still challenging to study hydrological connectivity due to the lack of event data of high temporal and spatial resolution required for such assessment (Jaramillo et al, 2018a;Kang & Guo, 2011;Wdowinski & Eriksson, 2009).…”

Section: Introductionmentioning

confidence: 99%

Using InSAR to identify hydrological connectivity and barriers in a highly fragmented wetland

Liu

Wang

Aminjafari

et al. 2020

Hydrological Processes

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Hydrological connectivity is a critical determinant of wetland functions and health, especially in wetlands that have been heavily fragmented and regulated by human activities. However, investigating hydrological connectivity in these wetlands is challenging due to the costs of high-resolution and large-scale monitoring required in order to identify hydrological barriers within the wetlands. To overcome this challenge, we here propose an interferometric synthetic aperture radar (InSAR)-based methodology to map hydrologic connectivity and identify hydrological barriers in fragmented wetlands. This methodology was applied along 70 transects across the Baiyangdian, the largest freshwater wetland in northern China, using Sentinel 1A and 1B data, covering the period 2016-2019. We generated 58 interferograms providing information on relative water level changes across the transects that showed the high coherence needed for the assessment of hydrological connectivity. We mapped the permanent and conditional (temporary) barriers affecting connectivity. In total, 11% of all transects are permanently disconnected by hydrological barriers across all interferograms and 58% of the transects are conditionally disconnected. Areas covered by reed grasslands show the most undisturbed hydrological connectivity while some of these barriers are the result of ditches and channels within the wetland and low water levels during different periods of the year. This study highlights the potential of the application of Wetland InSAR to determine hydrological connectivity and location of hydrological barriers in highly fragmented wetlands, and facilitates the study of hydrological processes from large spatial scales and long-time scales using remote sensing technique.

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“…The amount of delay depends mainly on the pressure, temperature and WV content, which vary significantly both in space and time (Reuveni et al, 2015). Geophysicists and geodesists have developed methods for estimating the degree to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric WV (Wdowinski and Eriksson, 2009). This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) that is recovered by stochastic filtering of the GPS data (Bevis et al, 1992(Bevis et al, , 1994Duan et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Combining METEOSAT-10 satellite image data with GPS tropospheric path delays to estimate regional Integrated Water Vapor (IWV) distribution

Leontiev¹,

Reuveni²

2016

Preprint

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Abstract. Using GPS satellites signals, we can study different processes and coupling mechanisms that can help us understand the physical conditions in the upper atmosphere, which might lead or act as proxies for severe weather events such as extreme storms and flooding. GPS signals received by ground stations are multi-purpose and can also provide estimates of tropospheric zenith delays, which can be converted into mm-accuracy Precipitable Water Vapor (PWV) using collocated pressure and temperature measurements on the ground. Here, we present the use of a dense regional GPS networks for extracting tropospheric zenith path delays combined with near Real Time (RT) METEOSAT-10 Water Vapor (WV) and surface temperature pixel intensity values (7.3 and 12.1 μm channels, respectively) in order to obtain absolute IWV (kg/m2) or PWV (mm) distribution. The results show good agreement between the absolute values obtained from our triangulation strategy based solely on GPS Zenith Total Delays (ZTD) and METEOSAT-10 surface temperature data compared with available radiosonde Precipitable IWV/PWV absolute values. The presented strategy can provide unprecedented temporal and special IWV/PWV distribution, which is needed as part of the accurate and comprehensive initial conditions provided by upper-air observation systems at temporal and spatial resolutions consistent with the models assimilating them.

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Geodesy in the 21st Century

Cited by 9 publications

References 1 publication

On the Potential of Improving WRF Model Forecasts by Assimilation of High-Resolution GPS-Derived Water-Vapor Maps Augmented with METEOSAT-11 Data

On the Potential of Improving WRF Model Forecasts by Assimilation of High-Resolution GPS-Derived Water-Vapor Maps Augmented with METEOSAT-11 Data

Using InSAR to identify hydrological connectivity and barriers in a highly fragmented wetland

Combining METEOSAT-10 satellite image data with GPS tropospheric path delays to estimate regional Integrated Water Vapor (IWV) distribution

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