Pom Model Research Articles

Factors Influencing Smallholder Farmers’ Decision to Abandon Introduced Sustainable Land Management Technologies in Central Ethiopia

The Ethiopian government has made efforts to rehabilitate degraded lands using a range of sustainable land management (SLM) initiatives. One of the key components was the use of improved structural soil and water conservation (SWC) technologies. However, the effectiveness of technology adoption varies greatly among households and abandoning previously accepted measures is a typical occurrence. Thus, this study sought to discover factors influencing smallholder farmers’ decisions to abandon already accepted SWC measures. The analysis was conducted based on data collected from 525 sample households surveyed in two districts in Central Ethiopia. An ordered cumulative logistic (POM) regression model was used to examine variables explaining households’ decision behavior. The study findings have revealed that sampled households were at different adoption stages, i.e., dis-adopters (22%), pilot-level adopters (14%) and adopters (64%). The results from the POM model also show that a range of variables influenced farmers’ dis-adoption decisions. Factors such as awareness about the risks of land degradation, access to training, incentives, land fragmentation, gender, full-time labor size, gentle slope plots, economic returns on investment and post-adoption follow-up were found to substantially influence smallholder farmers’ adoption discontinuance decisions. Thus, policymakers should consider these variables in designing strategies to overcome barriers to SLM practices.

Ocean Dynamics and Topographic Upwelling Around the Aracati Seamount - North Brazilian Chain From in situ Observations and Modeling Results

The hydrodynamics and the occurrence of topographic upwelling around the northern Brazilian seamount chain were investigated. Meteorological and physical oceanographic data collected under the REVIZEE-NE Program cruises around the Aracati Bank, the major and highly productive seamount in the area, were analyzed and used to force and validate simulations using the 3D Princeton Ocean Model (3D POM). The Tropical Water mass in the top 150-m layer and the South Atlantic Central Water (SACW) beneath it and down to a depth of 670 m was present. The thickness of the barrier layer varied seasonally, being thinner (2 m) during the austral spring (October–December) and thicker (20 m) during the austral autumn (April–June) when winds were stronger. The surface mixed and isothermal layers in the austral winter (July–September) were located at depths of 84 and 96 m, respectively. During the austral spring, those layers were located at depths of 6 and 8 m, respectively. The mean wind shear energy was 9.8 × 10–4 m2 s–2, and the energy of the surface gravity wave break was 10.8 × 10–2 m2 s–2, and both served to enhance vertical mixing in the area. A permanent thermocline between the 70- and 150-m depths was present throughout the year. The isohaline distribution followed an isotherm pattern of variation, but at times, the formation of low-salinity eddies was verified on the bank slope. The 3D POM model reproduced the thermohaline structure accurately. Temperature and salinity profiles indicated the existence of vertical water displacements over the bank and along the direction of the North Brazil Current, which is the strongest western boundary current crossing the equatorial Atlantic. The kinematic structure observed in the simulations indicated vertical velocities of O (10–3 m.s–1) in the upstream region of the bank during austral winter and summer seasons. During the summer, the most important vertical velocities were localized below the lower limit of the euphotic zone; while during the austral winter, these velocities were within the euphotic zone, thereby favoring primary producers.

State of the‐Art for Extrudate Swell of Molten Polymers: From Fundamental Understanding at Molecular Scale toward Optimal Die Design at Final Product Scale

AbstractPolymer extrudate swell is a rheological phenomenon taking place after polymer melt flow emerges the die exit of extrusion equipment, due to flow redistributions and molecular stress relaxations. The associated die design is based on the strategy of inhibiting or compensating the swelling behavior downstream the die exit. This contribution comprehensively highlights the current knowledge and plethora of experimental and modeling tools to tune extrudate swell of polymer melts. The novelty lies in the combined consideration of the impact and interplay of i) the processing parameters, ii) the die geometry, iii) the macromolecular characteristics (e.g., molar mass distribution and branching level), and iv) the additive macroscopic properties. Furthermore, the prediction of extrudate swell through various flow geometries by semiempirical expressions and fundamental viscoelastic constitutive models is compared. Specific focus is on the differential Phan–Thien–Tanner (PTT), the molecular‐based Double‐Convected POM–POM model (DCPP), and the integral Kaye–Bernstein–Kearsley–Zapas (K‐BKZ) model and their usefulness for 3D swelling descriptions, indicating the optimum model to understand the fundamental relation of molecular parameters and viscoelasticity. The relevance of such detailed analysis is also illustrated by including case studies addressing design at the final product scale.

Electrospinning of polymer solutions: An analysis of instability in a thinning jet with solvent evaporation

The present study examines the stability of a thinning straight jet in electrospinning process. The linear stability analysis is carried out to obtain the growth/decay rate of axisymmetric disturbance imposed on the thinning jet. The analysis captures the role of solvent evaporation in the stability behavior of the linear path of the electrospinning jet. In contrast to many prior stability analyses which consider the jet as a cylindrical filament with uniform radius, the present study analyzes the stability of a jet which exhibits thinning under realistic electrospinning conditions. Two different polymeric solutions are considered: the poly-isobutene (PIB) Boger fluid with low electrical conductivity and the highly conductive poly-ethylene oxide (PEO) solution in ethanol/water. At low extensional deformation, the rheology of the unentangled PIB-based Boger fluid is described by the Oldroyd-B model. The PEO solution, on the other hand, experiences a very high elongation rate due to the development of strong axial electric stress. The nonlinear rheology of the entangled PEO solution is appropriately described by the eXtended Pom–Pom (XPP) model, a variant of the classical tube model. The analysis reveals that the instability in low conductivity fluid is driven by the capillary forces, whereas the high conductivity fluid exhibits oscillatory conducting mode of instability driven by the coupled effect of axial electric field and surface charges. For both the reference fluids, the increase in solvent evaporation tends to decrease the disturbance growth rate to the extent that the axisymmetric instability is completely suppressed for a strong enough evaporation. The stabilizing role of solvent evaporation is attributed to the enhancement in fluid viscosity and elasticity due to increased polymer concentration upon evaporation. Thus, by suppressing the onset of axisymmetric instability during the straight jet path, solvent evaporation potentially helps produce smooth fibers without bead formation.

Assessment of the potential for dredged material dispersal from dumping sites in the Gulf of Gdańsk

PurposeEnvironment-friendly management of sites used for disposal of locally generated sedimentary material involves designation of an optimal dumping site location which will render the dredged material re-usable for beneficial purposes. The objective of this research was to determine whether wind, waves, and currents can induce transport of sediment from offshore dumping sites located at intermediate depths in the southern Baltic.Materials and methodsThe problem was addressed by exploring potential sediment transport from two sites located in the Gulf of Gdańsk at depths of about 20 m. A total of 29 combinations of hydrodynamic variables, representing the most extreme possible situations in the area, including eight theoretical uniform wind fields over the entire Baltic Sea from the W, NW, N, NE, E, SE, S, and SW sectors, the wind speed of 30 m s−1, as well as 21 historical extreme storms, retrieved from the HIPOCAS project database, were used.Results and discussionThe bottom velocities resulting from waves and currents at the dumping sites considered were computed using wave models (WAM, SWAN) and the M3D hydrodynamic model (based on the POM model). To estimate the velocities critical for bedload transport, formulae developed by Soulsby (1997) and Sawamoto and Yamashita (Proc Coastal Sediments 87:415–423, 1987) were used. The volumetric bedload transport was computed based on Meyer-Peter and Müller (1948). The model simulations demonstrated that, for the storm conditions analyzed, the current velocity in the area of the two dumping sites would be so low that it would practically not affect the magnitude of the bottom sediment transport. Thus, the resultant volume of bedload transported would be equal to that generated by the wave action. For the heaviest historical storm, the maximum transport is about 3 × 10−5 m2 s−1.ConclusionsUnder conditions of theoretical storms, the bottom orbital velocities would be higher and the resultant sediment transport would reach almost 7 × 10−5 m2 s−1 for northerly winds. However, this value is still very low compared with the volume of sediment being dumped. The findings of this study may prove useful in designation of future dumping sites.

Extreme bottom velocities induced by wind wave and currents in the Gulf of Gda\u0144sk

The principal goal of this study is to get some preliminary insights about the intensity of water movement generated by wind waves, and due to the currents in the bottom waters of Gulf of Gdańsk, during severe storms. The Gulf of Gdańsk is located in the southern Baltic Sea. This paper presents the results of analysis of wave and current-induced velocities during extreme wind conditions, which are determined based on long-term historical records. The bottom velocity fields originated from wind wave and wind currents, during analysed extreme wind events, are computed independently of each other. The long-term wind wave parameters for the Baltic Sea region are derived from the 44-year hindcast wave database generated in the framework of the project HIPOCAS funded by the European Union. The output from the numerical wave model WAM provides the boundary conditions for the model SWAN operating in high-resolution grid covering the area of the Gulf of Gdańsk. Wind current velocities are calculated with the M3D hydrodynamic model developed in the Institute of Oceanography of the University of Gdańsk based on the POM model. The three dimensional current fields together with trajectories of particle tracers spreading out of bottom boundary layer are modelled, and the calculated fields of bottom velocities are presented in the form of 2D maps. During northerly winds, causing in the Gulf of Gdańsk extreme waves and most significant wind-driven circulation, the wave-induced bottom velocities are greater than velocities due to currents. The current velocities in the bottom layer appeared to be smaller by an order of magnitude than the wave-induced bottom orbital velocities. Namely, during most severe northerly storms analysed, current bottom velocities ranged about 0.1–0.15 m/s, while the root mean square of wave-induced near-seabed velocities reached maximum values of up to 1.4 m/s in the southern part of Gulf of Gdańsk.

Analysis of the distribution of pollution in the Sea of Azov by the results of numerical simulation and data of satellite observations

The paper discusses methods of sharing information obtained by remote sensing of the sea surface from space and model solutions. The estimation of the quality of the model prediction is made depending on the intervals between the assimilation of satellite data. Numerical hydrodynamic modelling of the Azov Sea water area is performed on the basis of the POM model for real atmospheric forcing SKIRON in the period from 2013 to 2014. The peculiarities of spatial and temporal dynamics of the pollution in the Sea of Azov have been studied on the basis of a joint analysis of numerical simulation data and space monitoring data from the Terra/Aqua satellites. Based on the developed new model algorithms, the results of numerical simulation and data of satellite observations on the state of water in the Sea of Azov water area are summarized.

Mechanism of horizontal mass- and salt-exchange between the waters of continental slope and central part of the Black Sea

Estimation of horizontal salt transfer from the central part of the Black Sea to the continental slope is carried out based on numerical modeling. A box hydrodynamic model of the Black Sea based on the POM model is used. Horizontal transport caused by seasonal variability of vertical velocity in the central part of the Black Sea and horizontal turbulent diffusion is considered. In this work we demonstrate that, in the 0- to 30-m layer on average for the year, there is an outflow of salty water under the impact of both factors. In the surface layer, the transport caused by seasonal variability contributes significantly (30%). In the 80- to 150-m layer on average over the year, the waters from the continental slope arrive into the central part of the basin; they are characterized by higher salinity due to the inflow of the Marmara Sea waters across the Bosporus Strait.

The study of single station inverting the sea surface current by HF ground wave radar based on adjoint assimilation technology

This paper introduces the assimilation technology in an ocean dynamics model and discusses the feasibility of inverting the sea surface current in the detection zone by assimilating the sea current radial velocity detected by single station HF ground wave radar in ocean dynamics model. Based on the adjoint assimilation and POM model, the paper successfully inverts the sea surface current through single station HF ground wave radar in the Zhoushan sea area. The single station HF radar inversion results are also compared with the bistatic HF radar composite results and the fixed point measured results by Annderaa current meter. The error analysis shows that acquisition of flow velocity and flow direction data from the single station HF radar based on adjoint assimilation and POM model is viable and the data obtained have a high correlation and consistency with the flow field observed by HF radar.

Three-dimensional simulations of non-isothermal transient flow and flow-induced stresses during the viscoelastic fluid filling process

The three-dimensional (3D) viscoelastic polymer melt filling process in injection molding has always been regarded as a challenging two-phase flow problem. Numerical investigations concerning it are very limited, especially under the non-isothermal condition. Thus, this article presents a 3D non-isothermal two-phase model to investigate the flow-induced stresses during the viscoelastic fluid filling process. The viscoelastic behavior of polymer melt is predicted by the eXtended Pom–Pom (XPP) model, in which the temperature dependence of polymeric viscosity and relaxation times are described using the Arrhenius equation. The 3D governing equations are solved by a collocated finite volume method. The high resolution revised level set method coupled with a domain extension technique is extended to capture the 3D melt front interface in an irregular cavity. The collocated finite volume method and the revised level set solver are respectively validated using the XPP melts past a cylinder and the single vortex flow. Then the ability of the presented 3D two-phase model is verified by the isothermal Newtonian fluid filling process in a thin rectangular cavity. The numerical results are in good agreement with those reported in literature. Finally, the challenging problem of non-isothermal XPP fluid filling process in a 3D rectangular cavity with one cylindrical insert is investigated. The temperature field, flow-induced stresses and the corresponding rheological behaviors of polymer melt during 3D filling process are quantitatively predicted. Especially, the effects of processing conditions and energy source term on the two normal stress differences are discussed. It is found that melt temperature and injection velocity are the main factors that affect the normal stress differences. The obtained results should be helpful for improving the product properties in practical production.

Die-swell effect in draw resonance of polymeric spin-line

The role of die-swell in the stability of fiber spinning flow of entangled polymer melts is analyzed using the linear as well as finite amplitude stability analyses. The nonlinear extensional rheology of polymer is described by using the eXtended Pom–Pom (XPP) model which captures the strain hardening effect present in the realistic flows. The stability of the slender body fiber profile to axisymmetric disturbances is studied under the isothermal conditions. At the top end of the spinning flow near die-exit, the swelling in fiber cross-section area is introduced whose magnitude is governed both by the flow within the die and the outside spinning force. Introducing die-swell in the analysis significantly influences the stability of the spinning flow. The flexibility in the fiber profile at the upstream end of the flow, a feature absent in the previous analyses ignoring die-swell, plays a stabilizing role. However, for a given flow, die-swell implies stronger effective extension than indicated by the apparent draw ratio, defined based on capillary area. This higher effective extension tends to decrease the critical draw ratio for the onset of draw resonance, suggesting destabilizing role of die-swell. The destabilizing role is found to dominate in the overall stability behavior. The stability diagram is constructed by plotting the critical draw ratio for the onset of draw resonance against the flow Deborah number. The sensitivity of the stability behavior on the rheology parameters and the die-geometry has been studied. The finite amplitude disturbances are also considered using the weakly nonlinear stability analysis in order to understand the nature of flow in the proximity of the transition point. The flow exhibits supercritical Hopf bifurcation for low to moderate Deborah numbers, indicating the presence of an oscillatory steady state in the unstable regime. The amplitude of the oscillations in the fiber cross-section area is estimated. The finite amplitude bifurcation crosses over to the subcritical manifold as Deborah number is increased beyond a certain crossover value. The subcritical state for fast flows manifests in the form of unbounded growth of transient disturbances of amplitude greater than a certain threshold value. The die-swell effect tends to lower the Deborah number for the crossover to the subcritically unstable state.

Study on extrudate swell of polypropylene in double-lumen micro profile extrusion

One of the basic problems in the design of polymer extrusion dies for multi-lumen micro profiles is the previously unknown extrudate swells, since they are more complex than those in axisymmetric extrusions. To investigate the three-dimensional extrudate swell of such geometries, numerical simulations and experiments are performed for the extrusion of a double-lumen micro profile using polypropylene. The selected profile exhibits typical non-axisymmetric geometry, uneven thickness and micro-scale dimension. A double convected pom–pom model considering the micro size effect is proposed to characterize viscoelastic properties of the polymer melt. Predictions are compared with experimental results as well as simulations using the power law model, and show the capacity of the proposed model for assessing the anisotropic swelling quantitatively. Influences of micro size effect, volumetric flow rate and material parameters on extrudate swell are investigated by parametric studies. It is found that swell ratios of various positions on the extrudate cross section are significantly different. The swelling anisotropy degree is enhanced with increasing volumetric flow rate as well as material parameters of second normal force coefficient and branching degree, while it is suppressed as the ratio of orientation to stretching relaxation time increases. The influence mechanisms of material parameters on extrudate swell are also discussed in detail. It is suggested that the anisotropic extrudate swell induced by micro size effect is significant and should be taken into account in high accuracy micro profile extrusions.

A CaBER computational–experimental rheological study on human sputum

The main focus of this computational modelling study is to determine the extensional rheological response of sputum biofluids to provide a diagnostic tool (biomarker) for experimentally-based pathological analyses and clinical practice. This may be accomplished through advanced rheological parameterisation and characterisation of sputum samples, when considering extensional deformation flow situations that mimic sputum escalator deformation in the lung-airways. Sputum samples have been collected from patients (male and female, over fifty years of age) suffering from Chronic Obstructive Pulmonary Disease (COPD) at two stages of development: uninfected (stable or non-infective) state and infected (suffering exacerbations) state.Samples have been tested without any pre-treatment such as mechanical homogenisation. Experimental and numerical studies of Capillary Break-up Extensional Rheometer (CaBER) have been performed, from which comparison significant correlations are presented. Typically, the dynamic development of the mid-filament diameter is monitored during the process of necking and filament-failure (break-up). The aim is to link this type of data with that emerging from experimental/clinical trials to provide a biomarker revealing insight on state of disorder and resultant treatment.The rheology of sputum samples is represented through two rheological fluid modelling approaches: (i) a kinetic Single Extended pom–pom (SXPP) model and (ii) a time-dependent thixotropic Modified Bautista-Manero (MBM) model. These models are sufficiently rich to enable description of both network-structure and rheological properties, exhibiting viscoelastic response (memory), with strain-hardening/softening and shear-thinning properties.

Ice–ocean coupled computations for sea-ice prediction to support ice navigation in Arctic sea routes

With the recent rapid decrease in summer sea ice in the Arctic Ocean extending the navigation period in the Arctic sea routes (ASR), the precise prediction of ice distribution is crucial for safe and efficient navigation in the Arctic Ocean. In general, however, most of the available numerical models have exhibited significant uncertainties in short-term and narrow-area predictions, especially in marginal ice zones such as the ASR. In this study, we predict short-term sea-ice conditions in the ASR by using a mesoscale eddy-resolving ice–ocean coupled model that explicitly treats ice floe collisions in marginal ice zones. First, numerical issues associated with collision rheology in the ice–ocean coupled model (ice–Princeton Ocean Model [POM]) are discussed and resolved. A model for the whole of the Arctic Ocean with a coarser resolution (about 25 km) was developed to investigate the performance of the ice–POM model by examining the reproducibility of seasonal and interannual sea-ice variability. It was found that this coarser resolution model can reproduce seasonal and interannual sea-ice variations compared to observations, but it cannot be used to predict variations over the short-term, such as one to two weeks. Therefore, second, high-resolution (about 2.5 km) regional models were set up along the ASR to investigate the accuracy of short-term sea-ice predictions. High-resolution computations were able to reasonably reproduce the sea-ice extent compared to Advanced Microwave Scanning Radiometer–Earth Observing System satellite observations because of the improved expression of the ice–albedo feedback process and the ice–eddy interaction process.Keywords: Arctic sea ice; numerical simulation; floe collision; Arctic sea routes.(Published: 23 November 2015)To access the supplementary material for this article, please see supplementary files in the column to the right (under Article Tools).Citation: Polar Research 2015, 34, 25008, http://dx.doi.org/10.3402/polar.v34.25008

Long chain branched impact copolymer of polypropylene: Microstructure and rheology

A biphasic impact copolymer of polypropylene (ICP) was modified with peroxide by reactive extrusion process resulting in reduced melt flow index, improved melt strength, and higher die swell. The polymers were for the first time subjected to systematic rheological and microstructural characterization in an effort to understand their structure‐property relations. In shear rheological tests, the modified ICP displayed higher flow activation energy, reduced values of loss tangent and nearly equal frequency dependence of storage and loss modulli. The modified ICP also showed strain hardening behaviour in uniaxial extensional rheology and higher crystallization temperature in differential scanning calorimetry (DSC). All these are definitive indications of the presence of long chain branches (LCB). Fitting the rheological data of modified ICPs with the eXtended Pom Pom (XPP) model indicated the presence of LCB on the higher molecular weight fraction in the polymer, a result which was corroborated with multi‐detector high temperature gel permeation chromatography (HT‐GPC). More importantly, the matrix and rubber phases of the ICP were separately characterized for presence of long chain branching by rheology, DSC and HT‐GPC. The results indicate that while LCB existed in the matrix phase, microgels were present in both phases indicating that the reaction with peroxide occurred in both phases. POLYM. ENG. SCI., 55:1463–1474, 2015. © 2014 Society of Plastics Engineers

Responses of thermal structure and vertical dynamic structure of South China Sea to Typhoon Chanchu

The response of the South China Sea (SCS) to Typhoon Chanchu (2006) was examined using the MM5 and POM model. In the POM model, sea surface boundary conditions were forced by the simulation wind field from MM5, the velocity forcing was introduced in the eastern boundary and the computational schemes of heat fluxes at the surface were introduced. Comparison with the observation data shows that the simulated results are reliable. In the response process of the SCS to Typhoon Chanchu, the influence of the heat fluxes on thermal structure of the SCS was regionally different. Strong wind forcing would lead to upwelling phenomenon in the lateral boundary of deep water basin. Furthermore, the Ekman pumping theory was used to discuss subsurface upwelling and downwelling phenomenon in typhoon forced stage.

An ocean circulation model based on Eulerian forward-backward difference scheme and three-dimensional, primitive equations and its application in regional simulations

A two-time-level, three-dimensional numerical ocean circulation model is established with a two-level, single-step Eulerian time-difference scheme. The mathematical model of the large-scale oceanic motions is based on the terrain-following coordinated, Boussinesq, Reynolds-averaged primitive equations of ocean dynamics. A simple but very practical Eulerian forward-backward method is adopted to replace the most preferred leapfrog scheme as the time-difference method for both barotropic and baroclinic modes. The forward-backward method is of the second order of accuracy, requires only once of the function evaluation per time step, and is free of the computational mode inherent in the three-level schemes. It is superior in many respects to the original leapfrog and Asselin-filtered leapfrog schemes in the practical use. The performance of the newly-built circulation model is tested by simulating a barotropic (tides in marginal seas of China) and a baroclinic phenomenon (seasonal evolution of the Yellow Sea Cold Water Mass), respectively. The three-year time histories of four prognostic variables obtained by the POM model and the two-time-level model are compared in a regional simulation experiment for the northwest Pacific to further show the reliability of the two-level scheme circulation model.

Three-dimensional transient complex free surface flows: Numerical simulation of XPP fluid

In this paper we present a finite difference MAC-type approach for solving three-dimensional viscoelastic incompressible free surface flows governed by the eXtended Pom–Pom (XPP) model, considering a wide range of parameters. The numerical formulation presented in this work is an extension to three-dimensions of our implicit technique [Journal of Non-Newtonian Fluid Mechanics 166 (2011) 165–179] for solving two-dimensional viscoelastic free surface flows. To enhance the stability of the numerical method, we employ a combination of the projection method with an implicit technique for treating the pressure on the free surfaces. The differential constitutive equation of the fluid is solved using a second-order Runge–Kutta scheme. The numerical technique is validated by performing a mesh refinement study on a pipe flow, and the numerical results presented include the simulation of two complex viscoelastic free surface flows: extrudate-swell problem and jet buckling phenomenon.

Multi-period production planning under fuzzy conditions

In the real-world multi-period production/operations management (MP-POM) problems, the parameters must be estimated and they are frequently given by interval estimates. But for most POM models, these interval estimates must be translated into single numbers. This often results in errors and in the loss of a considerable amount of information. The purpose of this paper is to develop, apply, and illustrate a new fuzzy approach using fuzzy numbers to solve the interval MP-POM problem. It consists of employing appropriate fuzzy numbers to represent the interval estimates in the multi-stage decision problems; using the operations of fuzzy numbers combined with dynamic programming to solve the problem; and determining the required minimum/maximum fuzzy number through ranking techniques. To demonstrate the application of this approach, three MP-POM problems with fuzzy costs and/or fuzzy demands are solved. The main advantages of this approach are fuzzy representative solutions for the optimal production schedule and the minimum total cost in terms of interval units rather than single numbers. This enables the production engineers and operations managers to manage the production flexibly and control the costs effectively. A significant original contribution of this research is the development of an effective technique to solve the fuzzy MP-POM problems that have not been addressed thus far. Suggestions for future research include extending the proposed general fuzzy approach to solve large scale multistage fuzzy problems using computers; and to solve problems with fuzzy goals and constraints defined in different spaces.

Development of an operational coastal flooding early warning system

Abstract. Coastal floods are a consistent threat to oceanfront countries, causing major human suffering and substantial economic losses. Climate change is exacerbating the problem. An early warning system is essential to mitigate the loss of life and property from coastal flooding. The purpose of this study is to develop a coastal flooding early warning system (CoFEWs) by integrating existing sea-state monitoring technology, numerical ocean forecasting models, historical database and experiences, as well as computer science. The proposed system has capability of offering data for the past, information for the present and future. The system was developed for the Taiwanese coast due to its frequent threat by typhoons. An operational system without any manual work is the basic requirement of the system. Integration of various data sources is the system kernel. Numerical ocean models play an important role within the system because they provide data for assessment of possible flooding. The regional wave model (SWAN) that nested with the large domain wave model (NWW III) is operationally set up for coastal wave forecasting, in addition to the storm surge predicted by a POM model. Data assimilation technology is incorporated for enhanced accuracy. A warning signal is presented when the storm water level that accumulated from astronomical tide, storm surge, and wave-induced run-up exceeds the alarm sea level. This warning system has been in practical use for coastal flooding damage mitigation in Taiwan for years. An example of the system operation during the Typhoon Haitung which struck Taiwan in 2005 is illustrated in this study.