a bathymetry mapping approach combining log ratio and semianalytical models using four band multispectral imagery without ground data four band multispectral remote sensing imagery is widely used for a variety of purposes and has a long historical data record however most of the existing bathymetry inversion methods are either unable to determine the optimal solution through theoretical or semianalytical models due to the limited number of bands or their application is limited by the difficulty in obtaining in situ data in this article a log ratio model and a semianalytical model are combined to develop a new shallow water depth inversion method l s model using four band multispectral remote sensing images without the need for supporting truth data a case study was conducted for ganquan island in the south china sea using four band multispectral imagery from the geoeye 1 worldview 2 four bands selected sentinel 2 four bands selected and gaofen 1 satellites a sound range of 30 m was achieved when compared to lidar measured water depth data geoeye 1 worldview 2 sentinel 2 and gaofen 1 data have root mean square errors rmses of 1 33 1 97 m in addition compared with the results of the log ratio model trained using 200 lidar based depth readings the l s model results obtained for the four satellite types are similar in the rmse these results show that the l s model can achieve results that are close to those of the log ratio model without the need for external inputs this provides a feasible new method for bathymetry inversion in areas without truth data using only four band imagery

geographically adaptive inversion model for improving bathymetric retrieval from satellite multispectral imagery optical remote sensing imagery offers a cost effective alternative to echo sounding and bathymetric light detection and ranging surveys for deriving high density bottom depth estimates for coastal and inland water bodies the common practice of previous studies has been to calibrate a single global bathymetric inversion model for an entire image scene the performance of conventional global models is limited when the bottom type and water quality vary spatially within the scene to address the inadequacy of the conventional global models this paper presents a geographically adaptive inversion model to better estimate bottom depth although the general mathematical form of the geographically adaptive model is the same model parameters are optimally determined within a geographical region or a local area in contrast to the entire scene in the global inversion model by using high resolution ikonos and moderate resolution landsat satellite images we demonstrated that regionally and locally calibrated inversion models can effectively address the problems introduced by spatial heterogeneity in water quality and bottom type and provide significantly improved bathymetric estimates for more complex coastal waters

multispectral bathymetry using a simple physically based algorithm a simple method for estimating water depths from multispectral imagery is described and is applied to several ikonos data sets for which independent measurements of the water depth are available the methodology is based on a physical model for the shallow water reflectance and is capable of correcting for at least some range of water quality and bottom reflectance variations corrections for sun glint effects are applied prior to the application of the bathymetry algorithm the accuracy of the depth algorithm is determined by comparison with ground truth measurements and comparisons between the observed and calculated radiances are presented for one case to illustrate how the algorithm corrects for water attenuation and or bottom reflectance variations

new capabilities of the shoals airborne lidar bathymeter abstract the technology and methodology of airborne laser bathymetry are far from mature and new capabilities continue to be attained the shoals lidar system was recently augmented with the ability to utilize kinematic gps kgps with on the fly otf phase ambiguity resolution to permit the system to be used more extensively over land and for shoreline and other topographic mapping in addition to underwater bathymetry the seamless integration of these capabilities permits continuous surveying across the land water boundary importantly this also permits the production of sea bottom and topographic elevations without the need for concurrently measured water level data algorithms and procedures associated with the use of otf kgps are presented along with examples of performance

progressive deformation in anisotropic rocks abstract field observations show that the majority of crustal rocks possess a penetrative foliation defined by either compositional layering preferred orientations of crystals or both ductile deformation involving planar anisotropy of viscosity can be characterized by an anisotropy factor q n r s the ratio of the bulk viscosities in pure and simple shear respectively this ratio of the normal and shear viscosities may be determined analytically if the anisotropy is resolvable in a multilayer sequence with individual laminae of isotropic viscosity in that case the resistance to normal compression will be largely controlled by the competent layers whereas the resistance to shear is controlled by the soft layers more specifically the viscosities of the individual laminae add up like resistances in series and in parallel in the expressions for the normal and shear viscosities respectively the reorientation of the bulk stress within an anisotropic multilayer is systematically investigated for a range of anisotropy factors the mode of progressive deformation is controlled only by the anisotropy factor and the orientation of the principal deviatoric stress the rate of deformation can be scaled if the bulk normal viscosity and the magnitude of the principal deviatoric stress are also known the results are illustrated in a series of nomograms showing the spectrum of strain and rotation histories possible in rock volumes deforming with planar anisotropy it appears that with increasing anisotropy factor the deformation spectrum will narrow on simple shear irrespective of the orientation of the background or bulk deviatoric stress axes plane strain and isochoric conditions are assumed throughout the analysis

microwave backscatter from arctic lake ice and polarimetric implications polarimetric synthetic aperture radar satellite and ground based ku and x band scatterometer measurements are used to explore the scattering mechanism for ice in shallow arctic lakes wherein strong radiometric responses are seen for floating ice and low returns are evident where the ice has grounded scatterometer measurements confirm that high backscatter is from the ice water interface whereas polarimetric decomposition suggests that the dominant scattering mechanism from that interface is single bounce using fresnel equations a simple model for surface bounce from the ice water interface is proposed and its predictions are supported by experimental parameters such as co pol phase difference co pol ratio and the results of rigorous numerical modeling despite early research suggesting double bounce scattering from columnar air bubbles and the ice water interface as the dominant scattering mechanism in shallow lakes this paper strongly supports a single bounce model

stream functions and complex potentials implications for development of rock fabric and the continuum assumption abstract stream functions may be applied to study the development of ductile deformation patterns in rocks it is demonstrated how to derive the stream function and the associated complex potential from the velocity field of any particular flow finite deformation patterns are subsequently modelled analytically from this mathematical description of flow basic examples discussed are rigid body translation pure shear and composite flows due to simultaneous pure and simple shear a general stream function is obtained to describe the flow regime within a ductile deformation zone deforming by homogeneous plane strain by superposed pure and simple shear components the deformation patterns are visualized using analytical methods only the results are discussed in terms of fabric formation progressive deformation in a simple continuum modelled here mathematically using principles of fluid mechanics is compared with crystalline creep in rocks the validity of the continuum assumption is briefly outlined in view of recent experiments on particular synthetic monocrystalline aggregates octochloropropane ocp deformable at room conditions this provides a method for testing how crystalline deformation compares with an isotropic continuum

the role of stress in ductile deformation abstract the concept of progressive ductile deformation has previously been discussed mainly in kinematic terms little attention has been paid to the principal stresses that control the formation of ductile deformation patterns many deformation patterns of rocks may have been created in a stress field of stable orientation an equation derived here directly links the orientation of the major axis of deviatoric stress to the stretch and rotation components of plane isochoric deformation in isotropic rocks estimations of rotation and stretch of finite strain ellipsoids may therefore aid the recovery of palaeostress axes using a nomogram introduced here the inclination of the major principal deviatoric stress axis with respect to a reference plane controls both the particle movement paths and mode of progressive deformation the deformation tensor obtained by integrating the rate of displacement or velocity gradient equations is first expressed in time dependent terms comprising only the normal and shear components of the strain rate tensor mohr s equations of stress can then be used to link strain rates to the major principal stress responsible for them the rate of progressive deformation is determined by the rheology of the deforming rocks and the magnitude of the deviatoric stress this derivation yields a time dependent deformation tensor which is expressed in terms of the dynamic viscosity and the magnitude and orientation of the major deviatoric stress with respect to a reference plane the significance of this deformation tensor is illustrated by forward modelling using computer graphics these allow the progressive deformation of a unit volume of rock in response to deviatoric stresses of various stable orientations to be visualized

simulation based investigation of the generality of lyzenga s multispectral bathymetry formula in case 1 coral reef water abstract lyzenga s multispectral bathymetry formula has attracted considerable interest due to its simplicity however there has been little discussion of the effect that variation in optical conditions and bottom types which commonly appears in coral reef environments has on this formula s results the present paper evaluates lyzenga s multispectral bathymetry formula for a variety of optical conditions and bottom types a noiseless dataset of above water remote sensing reflectance from worldview 2 images over case 1 shallow coral reef water is simulated using a radiative transfer model the simulation based assessment shows that lyzenga s formula performs robustly with adequate generality and good accuracy under a range of conditions as expected the influence of bottom type on depth estimation accuracy is far greater than the influence of other optical parameters i e chlorophyll a concentration and solar zenith angle further based on the simulation dataset lyzenga s formula estimates depth when the bottom type is unknown almost as accurately as when the bottom type is known this study provides a better understanding of lyzenga s multispectral bathymetry formula under various optical conditions and bottom types

modelling floods in hydrologically complex lowland river reaches abstract this paper considers the modelling of lowland river reaches which contain complex within reach hydrological interactions it is clear that river and floodplain flow are the most important processes in terms of flood modelling in lowland systems although there are often important lateral inflows from catchments and hillslopes bounding the floodplain and from interactions between the river and the floodplain which can all affect the propagation of the flood wave previous models have often either considered a complex representation of the fluvial processes with no representation of the hydrological inflows into the reach bates p d anderson m g price d a hardy r j smith c n 1996 analysis and development of hydraulic models for floodplain flows in anderson m g walling d e bates p d eds floodplain processes wiley chichester pp 215 254 or have simulated a range of catchment processes with a poor representation of the river and floodplain abbot m b bathurst j c cunge j a o connell p e rasmussen j 1986 an introduction to the european hydrological system systeme hydrologique europeen she 2 structure of a physically based distributed modelling system journal of hydrology 87 61 77 hence this paper develops a modelling approach based on a two dimensional finite element hydraulic model of river and floodplain flow which is linked to a series of simple hydrological models that simulate catchment runoff surface and subsurface hillslope runoff and floodplain infiltration simulations show that the model is able to predict flood hydrographs for a series of flood events under a range of different hydrological conditions down a reach of the river severn uk furthermore the comparison of results from simulations using hydrological representations of different degrees of complexity suggest that there are restrictions on the necessary complexity of the hydrological components depending on the application of the model and the available validation data simple approaches to the reach scale hydrology may be sufficient if only the bulk outflow hydrograph is required by the user however more complex spatially and temporally distributed models appear to be required if predictions of the flood inundation extent are desired the simulations raise the issue of the application of distributed models and attempt to provide a framework for future research the results suggest that there is a need for the validation of the internal predictions of distributed models of flood flow and suggests a need for field data of river and floodplain interactions within long lowland river reaches

determination of water depth with high resolution satellite imagery over variable bottom types a standard algorithm for determining depth in clear water from passive sensors exists but it requires tuning of five parameters and does not retrieve depths where the bottom has an extremely low albedo to address these issues we developed an empirical solution using a ratio of reflectances that has only two tunable parameters and can be applied to low albedo features the two algorithms the standard linear transform and the new ratio transform were compared through analysis of ikonos satellite imagery against lidar bathymetry the coefficients for the ratio algorithm were tuned manually to a few depths from a nautical chart yet performed as well as the linear algorithm tuned using multiple linear regression against the lidar both algorithms compensate for variable bottom type and albedo sand pavement algae coral and retrieve bathymetry in water depths of less than 10 15 m however the linear transform does not distinguish depths 15 m and is more subject to variability across the studied atolls the ratio transform can in clear water retrieve depths in 25 m of water and shows greater stability between different areas it also performs slightly better in scattering turbidity than the linear transform the ratio algorithm is somewhat noisier and cannot always adequately resolve fine morphology structures smaller than 4 5 pixels in water depths 15 20 m in general the ratio transform is more robust than the linear transform

finite strains from non coaxial strain paths i computational techniques abstract matrix methods provide a powerful technique for calculating cumulative strain during non coaxial progressive deformation a straightforward derivation of the matrix equations representing the strain ellipsoid suitable for the field geologist is presented multiplication of transformation matrices used to model such strain paths results in non symmetric matrices describing strain ellipsoids with principal axes which cannot be directly solved for by standard eigenvector solution techniques the singular value decomposition is used instead the form of the strain ellipse used is completely general and with appropriate choice of the ellipse description matrix it can effect both pure and simple shear in modeling polyphase folded terrains the rotational component of the deformation is generally known at least in part from the relative orientations of deformed foliations and lineations matrices representing both the rotational and distortional components of strain can be multiplied to compute the resultant finite strain for any specified strain paths examples of some simple deformation paths demonstrate that large variations in the symmetry and magnitude of finite strains with orientation can be expected such variations are consistent with the range of strains observed in multiply folded terrains

multi band spectral matching inversion algorithm to derive water column properties in optically shallow waters an optimization of parameterization abstract deriving inherent optical properties iops and other water quality parameters from satellite remote sensing data covering optically shallow environments has historically been problematic due to difficulties in separating the benthic signal from that of the water column while recent advances have improved such retrievals most methods have high uncertainties for very shallow

assessment of flooding in urbanized ungauged basins a case study in the upper tiber area italy the reliability of a procedure for investigation of flooding into an ungauged river reach close to an urban area is investigated the approach is based on the application of a semi distributed rainfall runoff model for a gauged basin including the flood prone area and that furnishes the inlet flow conditions for a two dimensional hydraulic model whose computational domain is the urban area the flood event which occurred in october 1998 in the upper tiber river basin and caused significant damage in the town of pieve s stefano was used to test the approach the built up area often inundated is included in the gauged basin of the montedoglio dam 275 km2 for which the rainfall runoff model was adapted and calibrated through three flood events without over bank flow with the selected set of parameters the hydrological model was found reasonably accurate in simulating the discharge hydrograph of the three events whereas the flood event of october 1998 was simulated poorly with an error in peak discharge and time to peak of 58 and 20 respectively this discrepancy was ascribed to the combined effect of the rainfall spatial variability and a partial obstruction of the bridge located in pieve s stefano in fact taking account of the last hypothesis the hydraulic model reproduced with a fair accuracy the observed flooded urban area moreover incorporating into the hydrological model the flow resulting from a sudden cleaning of the obstruction which was simulated by a shock capturing one dimensional hydraulic model the discharge hydrograph at the basin outlet was well represented if the rainfall was supposed to have occurred in the region near the main channel this was simulated by reducing considerably the dynamic parameter the lag time of the instantaneous unit hydrograph for each homogeneous element into which the basin is divided the error in peak discharge and time to peak decreased by a few percent a sensitivity analysis of both the flooding volume involved in the shock wave and the lag time showed that this latter parameter requires a careful evaluation moreover the analysis of the hydrograph peak prediction due to error in rainfall input showed that the error in peak discharge was lower than that of the same input error quantity therefore the obtained results allowed us to support the hypothesis on the causes which triggered the complex event occurring in october 1998 and pointed out that the proposed procedure can be conveniently adopted for flood risk evaluation in ungauged river basins where a built up area is located the need for a more detailed analysis regarding the processes of runoff generation and flood routing is also highlighted copyright 2005 john wiley sons ltd

multiple optimal depth predictors analysis modpa for river bathymetry findings from spectroradiometry simulations and satellite imagery abstract remote mapping of bathymetry can play a key role in gaining spatial and temporal insight into fluvial processes ranging from hydraulics and morphodynamics to habitat conditions this research introduces multiple optimal depth predictors analysis modpa which combines previously developed depth predictors along with additional predictors derived from the intensity component of the hsi color space transformation modpa empirically selects a set of optimal predictors among all candidates utilizing partial least squares pls stepwise or principal component pc regression models the primary focus of this study was on shallow

hydraulic modelling calibration in small rivers by using coarse resolution synthetic aperture radar imagery this study investigates the potential of the low resolution images 150m derived by the advanced synthetic aperture radar onboard theenvisat satellite to calibrate a hydraulicmodel coupledwith a semidistributed hydrologicmodel applied to a subcatchment of the upper middletiberriver gennabasin 100 km in central italy wherein afloodevent occurredon28november2010causinghigh damages specifically for thisflood event anadvancedsyntheticapertureradar image is available for the peak regionof the discharge hydrograph different image processing techniques are used for the assessment of the flooded areas by using both a single image and a change detection image based on an additional dry reference image the satellite derived flooded areas are adopted for the calibration of the channel and floodplain manning s roughness coefficients of a quasi two dimensional hydraulic model applied to the study basin which allows to distinguish the main channel from the floodplain the inflows for the hydraulic model corresponding to each tributary of the main channel are determined by a semidistributed hydrologic model calibrated by using a set of historical flood events the hydraulic model calibration is also carried out by using the same set of historical flood events for the event of november 2010 the modelled discharge and water level hydrographs obtained with the two sets of manning roughness via satellite and historical calibration are compared with in situ observations at the outlet of the basin this application on a small catchment contributes to strengthen the value of remote sensing data confirming the potential of synthetic aperture radar imagery to reduce uncertainties in hydraulic modelling calibration copyright 2012 john wiley sons ltd

lag prediction in ungauged basins an investigation through actual data of the upper tiber river valley a comparative analysis of a variety of relationships for prediction of basin lag is performed by applying them to 23 basins located in the same geographical area and characterized by a rather similar vegetative cover the results of computations indicate that a lag area relationship with two constant parameters is the best predictor for most basins under different vegetative covers in the same basin only one parameter should be variable for a few other basins characterized by an anomalous drainage channel network of low density such a relationship can lead to unacceptable errors thus there is a need for an additional relationship to overcome this difficulty but a larger number of anomalous basins would be required for its determination an alternative procedure based on the use of the non linear kinematic wave which at least allows singling out the cases where a specific lag area relationship is not reliable is proposed this procedure therefore represents a partial but very useful solution to avoid considerable errors in hydrological practice copyright 2002 john wiley sons ltd

adaptive bathymetry estimation for shallow coastal waters using planet dove satellites abstract accurate bathymetric mapping of shallow waters above 15 m is essential for a wide range of scientific research government transport and industry globally satellite based bathymetry estimation approaches offer an alternative to traditional shipborne measurements especially given advancements in their spatial and temporal resolution of satellite imagery including the new planet dove constellation of 150 satellites providing daily coastal coverage dove satellites provide abundant cloud free images even over cloudy tropical coastal environment offering an opportunity to generate frequent bathymetry maps at high spatial resolution 4 m we developed a new adaptive bathymetry estimation algorithm for planet dove and similar satellites the algorithm adaptively tunes a depth estimator according to water column attenuation conditions the algorithm was tested at five diverse reef sites globally lighthouse reef belize saona island dominican republic st croix u s virgin islands heron island australia hawaii island u s using 31 satellite images from six dove satellites derived water depth was validated rmse 1 22 to 1 86 m with field measured sampling points 61 025 ranging in depth from 1 to 15 m algorithm performance was best at depths of 4 10 m this new adaptive algorithm can be effectively applied to derive high spatial resolution bathymetric maps from planet dove satellite imagery across a wide range of conditions

taylor mill analogues for patterns of flow and deformation in rocks abstract the giesekus design of taylor s four roll mill has been restored and is here used in novel flow visualizations of both pulsating and monotonously increasing strains the particle movement paths and progressive deformation patterns visualized in these physical experiments are in agreement with those previously calculated analytically and constructed graphically the progressive deformation of passive material markers is guided by flowlines circular flowlines accommodate rigid body rotations without deformation elliptical flowlines result in pulsating strains the maximum strain occurs when material particles which were initially at the short axis of the elliptical flowlines reach the long axis of the flow patterns monotonically increasing strains occur when flowlines are hyperbolic the insight thus gained is extrapolated to suggest practical methods and assumptions that allow the reconstruction of particle movement paths from deformation features commonly observed in rocks

progressive deformation of single layers under constantly oriented boundary stresses abstract competent single layers embedded in incompetent rock display a variety of structures if deformed by shortening or stretching folds boudins or pinch and swells similarly incompetent single layers hosted by more competent matrix rock may develop mullions inverse folds or both the change in length of material planes with time is controlled by the type of bulk deformation and the initial layer orientation the length and rotation history of material planes in a unit volume of rock is studied systematically by using for the first time deviatoric stresses of arbitrary but constant orientation making use of a fundamental deformation tensor the traces of the eight planes in the unit volume of rock used in the analysis are in the plane of deformation and are treated as passive marker lines the change in the length of these material lines is computed for arbitrary orientations of the principal deviatoric stresses the history of the length change and rotation of the passive marker planes carefully scaled against time is subsequently used to predict the structures which would evolve in similarly oriented single layers of either competent or incompetent rock the theoretical range of structural patterns evolving in the model is controlled by the orientations of the principal deviatoric stress conversely the geometry of deformation patterns in nature can be used to constrain the possible orientations of the palaeostress axes