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Bij de Vaate, I. (author), Slobbe, D.C. (author), Verlaan, M. (author)Multi-mission satellite altimetry data have been used to study the spatial and temporal variability in global storm surge water levels. This was done by means of a time-dependent extreme value analysis applied to the monthly maximum detided water levels. To account for the limited temporal resolution of the satellite data, the data were first...journal article 2024
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Klees, R. (author), Seitz, Kurt (author), Slobbe, D.C. (author)We present exact, closed-form expressions for the complete RTM correction and the harmonic correction to disturbing potential, gravity disturbance, gravity anomaly, and height anomaly. They need to be applied in quasi-geoid modelling whenever data points are buried inside the masses after residual terrain model (RTM) reduction and...journal article 2023
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Pelckmans, Ignace (author), Belliard, Jean-Philippe (author), Dominguez-Granda, Luis E. (author), Slobbe, D.C. (author), Temmerman, Stijn (author), Gourgue, Olivier (author)Intertidal wetlands, such as mangroves in the tropics, are increasingly recognized for their role in nature-based mitigation of coastal flood risks. Yet it is still poorly understood how effective they are at attenuating the propagation of extreme sea levels through large (order of 100 km2) estuarine or deltaic systems, with complex geometry...journal article 2023
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Ehlers, F. (author), Schlembach, Florian (author), Kleinherenbrink, M. (author), Slobbe, D.C. (author)We demonstrate in this work how we can take advantage of known unfocused SAR (UF-SAR) retracking methods (e.g. the physical SAMOSA model) for retracking of fully-focused SAR (FF-SAR) waveforms. Our insights are an important step towards consistent observations of sea surface height, significant wave height and backscatter coefficient (wind...journal article 2023
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Schlembach, Florian (author), Ehlers, F. (author), Kleinherenbrink, M. (author), Passaro, Marcello (author), Dettmering, Denise (author), Seitz, Florian (author), Slobbe, D.C. (author)Estimating the three geophysical variables significant wave height (SWH), sea surface height, and wind speed from satellite altimetry continues to be challenging in the coastal zone because the received radar echoes exhibit significant interference from strongly reflective targets such as sandbanks, sheltered bays, ships etc. Fully focused...journal article 2023
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Ehlers, F. (author), Slobbe, D.C. (author), Verlaan, M. (author), Kleinherenbrink, M. (author)Earlier work has empirically demonstrated some advantages of an increased posting rate of Synthetic Aperture Radar (SAR) altimeters beyond the expected ground resolution of about 320 m in Delay-Doppler (unfocused SAR, UFSAR) processing, corresponding to ∼20 Hz sampling. Higher posting rates of 40–80 Hz were shown to prevent spectral aliasing...journal article 2023
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Koune, I.C. (author), Rózsás, Árpád (author), Slobbe, Arthur (author), Cicirello, A. (author)The decreasing cost and improved sensor and monitoring system technology (e.g., fiber optics and strain gauges) have led to more measurements in close proximity to each other. When using such spatially dense measurement data in Bayesian system identification strategies, the correlation in the model prediction error can become significant. The...journal article 2023
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Klees, R. (author), Slobbe, D.C. (author)This paper investigates the full variance–covariance (VC) matrix of two high-resolution regional quasi-geoid models, utilizing a spherical radial basis function parameterization. Model parameters were estimated using weighted least-squares techniques and variance component estimation (VCE) for data weighting. The first model, known as the ...journal article 2023
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Afrasteh, Y. (author), Slobbe, D.C. (author), Sacher, M. (author), Verlaan, M. (author), Klees, R. (author), Guarneri, H. (author), Keyzer, L.M. (author), Pietrzak, J.D. (author), Snellen, M. (author)All realizations of the European Vertical Reference System (EVRS) computed so far are solely based on geopotential differences obtained by spirit leveling/gravimetry. As such, there are no direct connections between height benchmarks separated by large water bodies. In this study, such connections are added by means of model-based...journal article 2023
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Systematic errors observed in CryoSat-2 elevation swaths on mountain glaciers and their implicationsHaacker, J.M. (author), Wouters, B. (author), Slobbe, D.C. (author)Our awareness of ice caps' and mountain glaciers' sensitivity to climate change has driven major advances in the application of remote sensing techniques during the past decade. Regarding ESA's SARIn altimeter CryoSat-2, processing the full waveform to generate swaths of elevation estimates has become standard practice in regions of complex...journal article 2023
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Guarneri, H. (author), Verlaan, M. (author), Slobbe, D.C. (author), Veenstra, J. (author), Zijl, F. (author), Pietrzak, J.D. (author), Snellen, M. (author), Keyzer, L.M. (author), Afrasteh, Y. (author), Klees, R. (author)Both empirical and assimilative global ocean tidal models are significantly more accurate in the deep ocean than in shelf and coastal waters. In this study, we answered whether this is due to the quality of the models used to reduce tide and surge or the general approach to treat tide and surge as two separate components of the water level...journal article 2023
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Afrasteh, Y. (author), Slobbe, D.C. (author), Verlaan, M. (author), Klees, R. (author), Guarneri, H. (author), Keyzer, L.M. (author), Pietrzak, J.D. (author), Sacher, M. (author), Snellen, M. (author), Zijl, F. (author)The main objective of this study is to develop and analyze an empirical noise model for model-derived coastal summer mean water levels (SMWLs) and use that to obtain a more realistic quality impact of combining hydrodynamic leveling and Unified European Leveling Network (UELN) data in realizing the European Vertical Reference System (EVRS)....journal article 2023
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Tai, Ricky K. (author), Slobbe, Arthur T. (author), Roosen, M.A. (author)For structures whose structural safety cannot be demonstrated using the applicable code regulations, a nonlinear finite element analysis (NLFEA) can be used to investigate the structural behavior and maximum load capacity. The Dutch Ministry of Infrastructure and Water Management uses a dedicated guideline for NLFEA in such an assessment....conference paper 2023
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Altiparmaki, O. (author), Kleinherenbrink, M. (author), Naeije, M.C. (author), Slobbe, D.C. (author), Visser, P.N.A.M. (author)This article shows the first spectral analysis of fully-focused Synthetic Aperture Radar (FFSAR) altimetry data with the objective of studying backscatter modulations caused by swells. Swell waves distort the backscatter in altimetry radargrams by means of velocity and range bunching. These swell signatures are visible in the tail of the...journal article 2022
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Li, W. (author), Slobbe, D.C. (author), Lhermitte, S.L.M. (author)Satellite radar altimetry has been an important tool for cryospheric applications such as measuring ice-sheet height or assessing anomalies in snow and ice properties (e.g. the extensive melt in Greenland in 2012). Although accurate height measurements are key for such applications, slope-induced errors due to undulating topography within the...journal article 2022
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Bij de Vaate, I. (author), Martin, Ericka (author), Slobbe, D.C. (author), Naeije, M.C. (author), Verlaan, M. (author)In the Arctic Ocean, obtaining water levels from satellite altimetry is hampered by the presence of sea ice. Hence, water level retrieval requires accurate detection of fractures in the sea ice (leads). This paper describes a thorough assessment of various surface type classification methods, including a thresholding method, nine supervised-,...journal article 2022
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Guarneri, H. (author), Verlaan, M. (author), Slobbe, D.C. (author), Zijl, Firmijn (author), Pietrzak, J.D. (author), Keyzer, L.M. (author), Klees, R. (author)Satellite observations can help in the retrieval of constituents in shallow waters. Noise contamination, however, makes smaller constituents irretrievable and large sources of error. Throughout shallow areas, the constituent’s relevancy changes. For example, near an amphidromic point where M2 relevance drops, so does the potential of satellite...poster 2022
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Li, X. (author), Huang, J. (author), Klees, R. (author), Forsberg, R. (author), Willberg, M. (author), Slobbe, D.C. (author), Hwang, C. (author), Pail, R. (author)In this study, we compare six commonly used methods for the downward continuation of airborne gravity data. We consider exact and noisy simulated data on grids and along flight trajectories and real data from the GRAV-D airborne campaign. We use simulated and real surface gravity data for validation. The methods comprise spherical harmonic...journal article 2022
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Tidal dissipation from free drift sea ice in the Barents Sea assessed using GNSS beacon observationsVasulkar, A.N. (author), Verlaan, M. (author), Slobbe, D.C. (author), Kaleschke, Lars (author)One of the major challenges facing global hydrodynamic tidal models is the modelling of the interaction between sea ice and tides in high-latitude waters. Recent studies have shown strong seasonal correlation between sea ice and tides. Hence, it is important to accurately model the effect of sea ice in a tidal model. Presence of sea ice leads...journal article 2022
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Klees, R. (author), Seitz, K. (author), Slobbe, D.C. (author)In this paper, we derive improved expressions for the harmonic correction to gravity and, for the first time, expressions for the harmonic correction to potential and height anomaly. They need to be applied at stations buried inside the masses to transform internal values into harmonically downward continued values, which are then input to...journal article 2022