Temporal and spatial behaviour of rip channels in a multiple‐barred coastal system

A 15‐month data set of daily time‐averaged video images (Argus) has been analyzed to describe the spatial and temporal variability of the rip channels on a multiple‐barred coast at Noordwijk aan Zee, The Netherlands. The landward boundary of the intertidal bars and a proxy of the subtidal bar crest, defined as the intertidal and subtidal bar lines respectively, were derived from the Argus images. Local seaward‐directed deviations of the bar lines represent the cross‐shore and alongshore locations of the rip channels. The average intertidal rip spacing ( ) was 243 m, but the rips were not spaced regularly (σ_λ/ = 0.47). Some intertidal rips were observed to fill up during falling tide, but the majority remained open. The filled intertidal rip channels had more landward positions and migrated more slowly (2.4 versus 4.6 m/day) in the alongshore direction than the open intertidal rip channels. The number and the alongshore migration rate of open intertidal rip channels increased with the preceding wave heights (r = 0.26, p < 0.01) and alongshore component of the offshore wave power (r = 0.25, p < 0.01), respectively. The shape of the intertidal bar lines was similar to the subtidal bar line shape, suggesting that the intertidal morphology is coupled to the subtidal alongshore variability. The phase of two bar lines could vary from in phase (0°) to out of phase (180°). The phase changes gradually, due to different alongshore migration rates of the intertidal and subtidal bar lines. Copyright © 2009 John Wiley & Sons, Ltd.     

Coupling mechanisms in double sandbar systems. Part 2: impact on alongshore variability of inner‐bar rip channels

Double sandbar systems are common morphological features along sandy, wave‐dominated, micro‐ to meso‐tidal coastlines. In the companion paper, we demonstrated how various alongshore inner‐bar rip‐channel patterns can develop through morphological coupling to an alongshore‐variable outer bar. The simulated coupling patterns are, however, scarcely observed in the field. Instead, inner‐bar rip channels more often possess remarkably smaller and more variable alongshore length scales, suggesting that coupling mechanisms do not play a substantial role in the overall double‐sandbar dynamics. Here we use a numerical model to show that the relative importance of self‐organization and morphological coupling changes in favour of the latter with an increase in waterdepth variability along the outer‐bar crest. Furthermore, we find that the typical alongshore variability in inner‐bar rip‐channel scale is indicative of a mixture of self‐organization and morphological coupling rather than self‐organization alone. Morphological coupling may thus be more important to understanding and predicting the evolution of inner‐bar rip channels than previously envisaged. Copyright © 2010 John Wiley and Sons, Ltd.     

A note on cross‐profile morphology for glacial valleys

We provide an improvement to the Hirano–Aniya catenary model for the cross‐profile morphology of a glacial valley. Copyright © 2005 John Wiley & Sons, Ltd.     

Handling dip discrimination phenomenon in common‐reflection‐surface stack via combination of output‐imaging‐scheme and migration/demigration

In the application of a conventional common‐reflection‐surface (CRS) stack, it is well‐known that only one optimum stacking operator is determined for each zero‐offset sample to be simulated. As a result, the conflicting dip situations are not taken into account and only the most prominent event contributes to any a particular stack sample. In this paper, we name this phenomenon caused by conflicting dip problems as ‘dip discrimination phenomenon’. This phenomenon is not welcome because it not only leads to the loss of weak reflections and tips of diffractions in the final zero‐offset‐CRS stacked section but also to a deteriorated quality in subsequent migration. The common‐reflection‐surface stack with the output imaging scheme (CRS‐OIS) is a novel technique to implement a CRS stack based on a unified Kirchhoff imaging approach. As far as dealing with conflicting dip problems is concerned, the CRS‐OIS is a better option than a conventional CRS stack. However, we think the CRS‐OIS can do more in this aspect. In this paper, we propose a workflow to handle the dip discrimination phenomenon based on a cascaded implementation of prestack time migration, CRS‐OIS and prestack time demigration. Firstly, a common offset prestack time migration is implemented. Then, a CRS‐OIS is applied to the time‐migrated common offset gather. Afterwards, a prestack time demigration is performed to reconstruct each unmigrated common offset gather with its reflections being greatly enhanced and diffractions being well preserved. Compared with existing techniques dealing with conflicting dip problems, the technique presented in this paper preserves most of the diffractions and accounts for reflections from all possible dips properly. More importantly, both the post‐stacked data set and prestacked data set can be of much better quality after the implementation of the presented scheme. It serves as a promising alternative to other techniques except that it cannot provide the typical CRS wavefield attributes. The numerical tests on a synthetic Marmousi data set and a real 2D marine data set demonstrated its effectiveness and robustness.     

Observations on sandbar behaviour along a man‐made curved coast

Sandbars, submerged ridges of sand parallel to the shoreline, affect surfzone circulation, beach topography and beach width. Under time‐varying wave forcing, sandbars may migrate onshore and offshore, referred to as two‐dimensional (2D) behaviour, and vary in planshape from alongshore uniform ridges to alongshore non‐uniform ridges through the growth and decay of three‐dimensional (3D) patterns, referred to as 3D behaviour. Although 2D and 3D sandbar behaviour is reasonably well understood along straight coasts, this is not the case for curved coasts, where the curvature can invoke spatial variability in wave forcing. Here, we analyse sandbar behaviour along the ～3000 m man‐made curved coastline of the Sand Engine, Netherlands, and determine the wave conditions governing this behaviour. 2D and 3D behaviour was quantified within a box north and west of the Sand Engine's tip, respectively, using a 2.4‐year dataset of daily low‐tide video images and a sparser bathymetric dataset. The northern and western sides behaved similarly in terms of 2D behaviour, with seasonal onshore and offshore migration, resulting in a stable position on inter‐annual timescales. However, both sandbar geometry and 3D behaviour differed substantially between both sides. The geometric differences (bar shape, bar crest depth and wavelength of 3D patterns) are consistent with computed alongshore differences in breaker height due to refraction. The differences in the timing in growth, decay and morphological coupling of 3D patterns in the sandbar and shoreline are likely related to differences in the local wave angle, imposed by the curved coast. Similar dependency of bar behaviour on local wave height and angle may be expected elsewhere along curved coasts, e.g. shoreline sandwaves, cuspate forelands or embayed beaches. Copyright © 2017 John Wiley & Sons, Ltd.     

Suppression of near‐surface scattered body‐to‐surface waves: a steerable and nonlinear filtering approach

We present an approach based on local‐slope estimation for the separation of scattered surface waves from reflected body waves. The direct and scattered surface waves contain a significant amount of seismic energy. They present great challenges in land seismic data acquisition and processing, particularly in arid regions with complex near‐surface heterogeneities (e.g., dry river beds, wadis/large escarpments, and karst features). The near‐surface scattered body‐to‐surface waves, which have comparable amplitudes to reflections, can mask the seismic reflections. These difficulties, added to large amplitude direct and back‐scattered surface (Rayleigh) waves, create a major reduction in signal‐to‐noise ratio and degrade the final sub‐surface image quality. Removal of these waves can be difficult using conventional filtering methods, such as an filter, without distorting the reflected signal. The filtering algorithm we present is based on predicting the spatially varying slope of the noise, using steerable filters, and separating the signal and noise components by applying a directional nonlinear filter oriented toward the noise direction to predict the noise and then subtract it from the data. The slope estimation step using steerable filters is very efficient. It requires only a linear combination of a set of basis filters at fixed orientation to synthesize an image filtered at an arbitrary orientation. We apply our filtering approach to simulated data as well as to seismic data recorded in the field to suppress the scattered surface waves from reflected body waves, and we demonstrate its superiority over conventional techniques in signal preservation and noise suppression.     

Seasonal variation of crescentic dune morphology and morphometry,Strzelecki–Simpson Desert,Australia

The general absence of contemporary dune building in the Australian arid zone finds the occurrence of crescentic dune genesis and evolution at Gurra Gurra waterhole, a somewhat enigmatic event amongst prevalent inactive linear dunescapes. Crescentic dune construction is geographically restricted to areas of dominant unidirectional high windiness and minimal vegetation, parameters that are generally uncommon in arid Australia today. The influence of seasonal multidirectional winds can see dune form undergo continual transition between quasi‐equilibrium and disequilibrium. Such dynamic antithesis is depicted in seasonal mathematical comparisons of the planimetric attributes, length and width. Dimensional equilibrium is a transient feature at Gurra Gurra waterhole and not characteristic of this dunescape. Copyright © 2001 John Wiley & Sons, Ltd.     

In situ characterization of grain‐scale fluvial morphology using Terrestrial Laser Scanning

The grain‐scale morphology of fluvial sediments is an important control on the character and dynamics of river systems; however current understanding of its role is limited by the difficulties of robustly quantifying field surface morphology. Terrestrial Laser Scanning (TLS) offers a new methodology for the rapid acquisition of high‐resolution and high‐precision surface elevation data from in situ sediments. To date, most environmental and fluvial applications of TLS have focused on large‐scale systems, capturing macroscale morphologies. Application of this new technology at scales necessary to characterize the complexity of grain‐scale fluvial sediments therefore requires a robust assessment of the quality and sources of errors in close‐range TLS data. This paper describes both laboratory and field experiments designed to evaluate close‐range TLS for sedimentological applications and to develop protocols for data acquisition. In the former, controlled experiments comprising high‐resolution scans of white, grey and black planes and a sphere were used to quantify the magnitude and source of three‐dimensional (3D) point errors resulting from a combination of surface geometry, reflectivity effects and inherent instrument precision. Subsequently, a methodology for the collection and processing of grain‐scale TLS data is described through an application to a coarse grained gravel system, the River Feshie (D₅₀ 32 to 63 mm). This stepwise strategy incorporates averaging repeat scans and filtering scan artefact and non‐surface points using local 3D search algorithms. The sensitivity of the results to the filter parameter values are assessed by careful internal validation of Digital Terrain Models (DTMs) created from the resulting point cloud data. The transferability of this methodology is assessed through application to a second river, Bury Green Brook, dominated by finer gravel (D₅₀ 18 to 33 mm). The factor limiting the resolution of DTMs created from this second dataset was found to be the relative sizes of the laser footprint and smallest grains. Copyright © 2009 John Wiley & Sons, Ltd.     

Spatio‐temporal distribution of near‐surface and root zone soil moisture at the catchment scale

Soil moisture is highly variable both spatially and temporally. It is widely recognized that improving the knowledge and understanding of soil moisture and the processes underpinning its spatial and temporal distribution is critical. This paper addresses the relationship between near‐surface and root zone soil moisture, the way in which they vary spatially and temporally, and the effect of sampling design for determining catchment scale soil moisture dynamics. In this study, catchment scale near‐surface (0–50 mm) and root zone (0–300 mm) soil moisture were monitored over a four‐week period. Measurements of near‐surface soil moisture were recorded at various resolutions, and near‐surface and root zone soil moisture data were also monitored continuously within a network of recording sensors. Catchment average near‐surface soil moisture derived from detailed spatial measurements and continuous observations at fixed points were found to be significantly correlated (r² = 0·96; P = 0·0063; n = 4). Root zone soil moisture was also found to be highly correlated with catchment average near‐surface, continuously monitored (r² = 0·81; P < 0·0001; n = 26) and with detailed spatial measurements of near‐surface soil moisture (r² = 0·84). The weaker relationship observed between near‐surface and root zone soil moisture is considered to be caused by the different responses to rainfall and the different factors controlling soil moisture for the soil depths of 0–50 mm and 0–300 mm. Aspect is considered to be the main factor influencing the spatial and temporal distribution of near‐surface soil moisture, while topography and soil type are considered important for root zone soil moisture. The ability of a limited number of monitoring stations to provide accurate estimates of catchment scale average soil moisture for both near‐surface and root zone is thus demonstrated, as opposed to high resolution spatial measurements. Similarly, the use of near‐surface soil moisture measurements to obtain a reliable estimate of deeper soil moisture levels at the small catchment scale was demonstrated. Copyright © 2007 John Wiley & Sons, Ltd.     

A 14.7 Ka record of earth surface processes from the arid‐monsoon transitional zone of China

The stability of Earth's critical zone is intimately linked with erosion, weathering and vegetation type and density. Therefore, it affects global biogeochemical processes which in turn affect the global climate by absorbing and reflecting solar radiation, and by altering fluxes of heat, water vapour, carbon dioxide and other trace gases through various feedback mechanisms. However, there is a lack of knowledge about how Earth's critical zone processes have changed over time and their link with past monsoon variability, especially in Asia. The study of lake sediments, which contain a suite of inorganic elemental and isotopic proxies, may facilitate the understanding of the Earth's critical zone processes on millennial timescales. Here we reconstruct the history of erosion–weathering–vegetation interactions since ~14.7 ka using geochemical records from a radiocarbon‐dated sediment core from Lake Gonghai in the monsoon‐arid transitional zone of north China. Detrital (Al, Ti, K, Rb) and authigenic (Ca, Sr) elemental records reveal distinct, millennial‐scale, late deglacial‐Holocene erosion and weathering patterns and transitions with the former (latter) elements showing higher (lower) values in warm intervals and vice versa. Chemical Index of Alteration (CIA) molar, a humidity proxy, suggests low humidity during the late deglacial ~11.5–14.7 ka, high humidity during the early‐mid Holocene ~11.5–3.2 ka, and intermediate humidity during the late Holocene interval since ~3.2 ka. The results of cross‐spectral analysis and comparison of our records with other climate reconstructions also suggest a pattern of orbitally‐phased humidity changes in north China. Overall, our results provide evidence for the solar‐forcing of Earth's surface processes in mid‐latitude China under natural climatic conditions. Copyright © 2017 John Wiley & Sons, Ltd.     

Frequency‐dependent multi‐offset phase analysis of surface waves: an example of high‐resolution characterization of a riparian aquifer

Multi‐offset phase analysis of seismic surface waves is an established technique for the extraction of dispersion curves with high spatial resolution and, consequently, for the investigation of the subsurface in terms of shear wave velocity distribution. However, field applications are rarely documented in the published literature. In this paper, we discuss an implementation of the multi‐offset phase analysis consisting of the estimation of the Rayleigh wave velocity by means of a moving window with a frequency‐dependent length. This allows maximizing the lateral resolution at high frequencies while warranting stability at the lower frequencies. In this way, we can retrieve the shallow lateral variability with high accuracy and, at the same time, obtain a robust surface‐wave velocity measurement at depth. In this paper, we apply this methodology to a dataset collected for hydrogeophysical purposes and compare the inversion results with those obtained by using refraction seismics and electrical resistivity tomography. The surface‐wave results are in good agreement with those provided by the other methods and demonstrate a superior capability in retrieving both lateral and vertical velocity variations, including inversions. Our results are further corroborated by the lithological information from a borehole drilled on the acquisition line. The availability of multi‐offset phase analysis data also allows disentangling a fairly complex interpretation of the other geophysical results.     

Mountain ordering: A method for classifying mountains based on their morphometry

A new method for classifying mountain morphology, ‘mountain ordering,’ is proposed, and quantitative expressions for various morphological parameters of two ordered mountains in northern Japan were obtained using this method. Mountain order was defined in terms of the closed contour lines on a topographic map. A set of closed, concentric contour lines defines a first-order mountain. Higher-order mountains can be defined as a set of closed contour lines that contain lower-order mountains and that have only one closed contour line for each elevation; they are identified as m + 1th-order mountains, where m represents the order of the enclosed, lower-order mountains. The geomorphometry for a mountain ordered according to this definition permits the identification of systematic relationships between various morphological parameters. The relationships between mountain order and these morphological parameters follow a form similar to that of Horton's laws, and permit the calculation of the ratios of number, area and height; these parameters are sufficient to express the magnitude of a mountain's dissection. The size–frequency distribution for area and height shows self-similarity for ordered mountains, and determines their fractal dimensions. Furthermore, the relationship between area and height, which has the form of a power function, describes the relief structure of ordered mountains. Copyright © 1999 John Wiley & Sons, Ltd.     

Wet surface resistance of forest canopy in monsoon Asia: Implications for eddy‐covariance measurement of evapotranspiration

During the Asian monsoon period, intense precipitation commonly occurs for an extended period in accompaniment with a reduction in solar radiation. This suggests that wet surface evapotranspiration is an important contributor to the total evapotranspiration. Therefore, investigating evapotranspiration over a wet canopy surface is critical to achieve a better understanding of water and energy cycles in Asia. In this study, we estimated surface resistances under wet conditions in a mixed forest influenced by the East Asian monsoon system. We showed that the surface resistance had a non‐negligible magnitude of about 30 sm^?1 even under wet conditions. We also found that the ratio between the actual and potential evapotranspiration depended on the friction velocity regardless of the time of day. Our analyses suggest that this dependency is tightly related to the underestimation of turbulent fluxes by the eddy‐covariance system under wet surface conditions. Together, our findings suggest that the wet surface resistance, although small, should be considered in simulating evapotranspiration because the forest ecosystem is strongly coupled to the overlying atmosphere. This could significantly improve the shortcomings of evapotranspiration measurement and modeling in Asian forest canopies influenced by the monsoon system. Copyright © 2012 John Wiley & Sons, Ltd.     

Removal of water‐surface reflection effects with a temporal minimum filter for UAV‐based shallow‐water photogrammetry

The recent development of structure‐from‐motion (SfM) and multi‐view stereo (MVS) photogrammetry techniques has enabled semi‐automatic high‐resolution bathymetry using aerial images taken by consumer‐grade digital cameras mounted on unmanned aerial vehicles (UAVs). However, the applicability of these techniques is sometimes limited by sun and sky reflections at the water surface, which render the point‐cloud density and accuracy insufficient. In this research, we present a new imaging technique to suppress the effect of these water‐surface reflections. In this technique, we order a drone to take a short video instead of a still picture at each waypoint. We then apply a temporal minimum filter to the video. This filter extracts the smallest RGB values in all the video frames for each pixel, and composes an image with greatly reduced reflection effects. To assess the performance of this technique, we applied it at three small shallow‐water sites. Specifically, we evaluated the effect of the technique on the point cloud density and the accuracy and precision of the photogrammetry. The results showed that the proposed technique achieved a far denser point cloud than the case in which a randomly chosen frame was used for each waypoint, and also showed better overall accuracy and precision in estimating water‐bottom elevation. The effectiveness of this new technique should depend on the surface wave state and sky radiance distribution, and this dependence, as well as the applicability to large areas, should be investigated in future research. Copyright © 2018 John Wiley & Sons, Ltd.     

A finite element model for simulating surface run‐off and unsaturated seepage flow in the shallow subsurface

This work introduces water–air two‐phase flow into integrated surface–subsurface flow by simulating rainfall infiltration and run‐off production on a soil slope with the finite element method. The numerical model is formulated by partial differential equations for hydrostatic shallow flow and water–air two‐phase flow in the shallow subsurface. Finite element computing formats and solution strategies are presented to obtain a numerical solution for the coupled model. An unsaturated seepage flow process is first simulated by water–air two‐phase flow under the atmospheric pressure boundary condition to obtain the rainfall infiltration rate. Then, the rainfall infiltration rate is used as an input parameter to solve the surface run‐off equations and determine the value of the surface run‐off depth. In the next iteration, the pressure boundary condition of unsaturated seepage flow is adjusted by the surface run‐off depth. The coupling process is achieved by updating the rainfall infiltration rate and surface run‐off depth sequentially until the convergence criteria are reached in a time step. A well‐conducted surface run‐off experiment and traditional surface–subsurface model are used to validate the new model. Comparisons with the traditional surface–subsurface model show that the initiation time of surface run‐off calculated by the proposed model is earlier and that the water depth is larger, thus providing values that are closer to the experimental results.     

Coil response inversion for very early time modelling of helicopter‐borne time‐domain electromagnetic data and mapping of near‐surface geological layers

Very early times in the order of 2–3 μs from the end of the turn‐off ramp for time‐domain electromagnetic systems are crucial for obtaining a detailed resolution of the near‐surface geology in the depth interval 0–20 m. For transient electromagnetic systems working in the off time, an electric current is abruptly turned off in a large transmitter loop causing a secondary electromagnetic field to be generated by the eddy currents induced in the ground. Often, however, there is still a residual primary field generated by remaining slowly decaying currents in the transmitter loop. The decay disturbs or biases the earth response data at the very early times. These biased data must be culled, or some specific processing must be applied in order to compensate or remove the residual primary field. As the bias response can be attributed to decaying currents with its time constantly controlled by the geometry of the transmitter loop, we denote it the ‘Coil Response’. The modelling of a helicopter‐borne time‐domain system by an equivalent electronic circuit shows that the time decay of the coil response remains identical whatever the position of the receiver loop, which is confirmed by field measurements. The modelling also shows that the coil response has a theoretical zero location and positioning the receiver coil at the zero location eliminates the coil response completely. However, spatial variations of the coil response around the zero location are not insignificant and even a few cm deformation of the carrier frame will introduce a small coil response. Here we present an approach for subtracting the coil response from the data by measuring it at high altitudes and then including an extra shift factor into the inversion scheme. The scheme is successfully applied to data from the SkyTEM system and enables the use of very early time gates, as early as 2–3 μs from the end of the ramp, or 5–6 μs from the beginning of the ramp. Applied to a large‐scale airborne electromagnetic survey, the coil response compensation provides airborne electromagnetic methods with a hitherto unseen good resolution of shallow geological layers in the depth interval 0–20 m. This is proved by comparing results from the airborne electromagnetic survey to more than 100 km of Electrical Resistivity Tomography measured with 5 m electrode spacing.     

Assessment of drone‐based surface flow observations

Remote surface flow observations are crucial for improving the comprehension of hydrological phenomena. A recent advancement in remote hydrological measurements involves the use of drones for generating surface flow‐velocity field maps through large‐scale particle image velocimetry (LSPIV). In this work, we perform a comparative analysis of drone‐based LSPIV with fixed implementations. Quantitative indices are introduced to test the efficiency of the techniques with regards to measurement accuracy, sensitivity to the transit of tracers, and platform mobility. Experimental findings support drone‐based observations in outdoor settings. Specifically, measurements from the aerial platform are more sensitive to the transit of tracers and closer to benchmark values than traditional LSPIV implementations. Future work should aim at improving the stability of the aerial platform and mitigating the effects of tracer scarcity. Copyright © 2015 John Wiley & Sons, Ltd.     

A macro‐element model for inelastic building analysis

A three‐dimensional model for approximate inelastic analysis of buildings is presented herein. The model is based on a single macro‐element per building storey. The inelastic properties of the model are characterized by the so‐called ultimate storey shear and torque (USST) surfaces. Different algorithms for the construction of these surfaces, as well as their applications in building modelling, are presented and discussed. Two alternative procedures are developed to integrate the force‐deformation constitutive relationship of the macro‐elements. The first one follows the exact trajectory of the load path of the structure on the USST, and the second uses linear programming without ever forming the USST surface. The accuracy of the model and integration procedure is evaluated by means of the earthquake response of single‐storey systems. The model and integration procedure developed is finally used to compute the inelastic response of a seven‐storey R/C building. The results of this investigation show that the model proposed, although approximate, can be effective in estimating the inelastic deformation demand of a building. It also enables the engineer to capture and interpret important features of the three‐dimensional inelastic response of a structure even before performing any inelastic dynamic analysis. Copyright © 2000 John Wiley & Sons, Ltd.     

Earthquake fault‐induced surface rupture—A hybrid strong ground motion simulation technique and discussion for structural design

Unique to the near‐source region of a large earthquake is the occurrence of strong impulsive ground motion and surface faulting referred to as ‘fling‐step’ motion. The objective of this study is to synthesize broad‐band time histories over a wide range of frequencies by characterizing rupture directivity and fling effects from the comprehensive strong motion database of the near‐fault Chi‐Chi event. To aid in the generation of these special types of ground motions, a hybrid modeling technique is introduced based on the stochastic finite‐fault radiation method and an efficient analytical approach to incorporate the observed low‐frequency features in the records close to the ruptured fault. The results show that the overall agreement among the developed hybrid methodology and recorded waveforms and response spectra is quite satisfying. A brief discussion on the design of infrastructures near seismic fault is also included. Copyright © 2011 John Wiley & Sons, Ltd.     

Estimation and application of near‐surface full waveform redatuming operators

Land seismic data quality can be severely affected by near‐surface anomalies. The imprint of a complex near‐surface can be removed by redatuming the data to a level below the surface, from where the subsurface structures are assumed to be relatively smooth. However, to derive a velocity‐depth model that explains the propagation effects of the near‐surface is a non‐trivial task. Therefore, an alternative approach has been proposed, where the redatuming operators are obtained in a data‐driven manner from the reflection event related to the datum. In the current implementation, the estimation of these redatuming operators is done in terms of traveltimes only, based on a high‐frequency approximation. The accompanying amplitudes are usually derived from a local homogeneous medium, which is obviously a simplification of reality. Such parametrization has produced encouraging results in the past but cannot completely remove the near‐surface complexities, leaving artefacts in the redatumed results. In this paper we propose a method that estimates the redatuming operators directly from the data, i.e., without using a velocity model, in a full waveform manner, such that detailed amplitude and phase variations are included. The method directly outputs the inverse propagation operators that are needed for true‐amplitude redatuming. Based on 2D synthetic data it is demonstrated that the resulting redatuming quality is improved and artefacts are reduced.