A statistical model of global wave height analysis was developed based on the JRA-55 reanalysis data and applied to future projections of wave climate change under several future scenarios. Mean and extreme wave heights were estimated globally using the statistical wave model. The estimated mean wave heights in future climates show increase in the Northwestern Pacific and decrease in the Northestern Pacific, middle latitude and around the equator. The estimated extreme wave heights in future climates shows different trends from mean one depending on the future greenhouse gas emission scenarios.

View full abstract

 The intensity of tropical cyclones due to climate change is projected to be likely increase. Thus, risk of coastal disaster may become severer, and reliable projection of future storm surge change has become more important for coastal disaster mitigations. Although the horizontal resolution of General Circulation Model (GCM) is getting increase to generate tropical cyclones, GCM still has unignorable bias compare to Regional Climate Model (RCM). This study develops statistical bias correction method of typhoon characteristics (track, pressure, and wind speed) projected in GCMs to contribute for more accurate future storm surge projection. Future change in storm surge is projected using the bias corrected typhoons from GCM outputs as a driving force. Ensemble storm surge simulations indicate uncertainty of future change projection of storm surge and necessity of more number of ensemble climate model experiments.

View full abstract

 In several decades, numbers of studies have been conducted to assess the impact of climate changes on tropical cyclones. It is reported that tropical cyclones will become more intense in furure and indicated that storm surge risks will be significantly severer. In the present study, we conducted a series of Typhoon Vera storm surge simulations as changing scenario-based typhoon tracks under pseudo global warming scenarios and model-based ones by a global stochastic tropical cyclone model in the Ise Bay. We aimed to take a look at the maximum surge level as changing the central pressure depression and track of Typhoon Vera in order to estimate a group of typhoons that induces the highest surge levels in the Ise Bay. Our results showed that the maximum surge level due to Typhoon Vera with the worst track is 1.5 m higher than the observed maximum surge level due to the typhoon with the original track. In addition, we estimated that its return period is 430 year.

View full abstract

 In order to compare typhoon intensity change among global warming scenarios in the late 21st century, pseudo-global warming experiments have been conducted in this study using a high-resolution typhoon model based on the mesoscale meteorological model MM5. The high-resolution typhoon model is a coupled atmosphere-ocean model with an automatic movable nesting domain, which can accurately reproduce the internal structure and intensity of a typhoon from its genesis to dissipation. Intercomparison of three pseudo-global warming experiments (SRES B1, A1B and A2) indicates that the typhoon intensity is averagely increased in all scenarios, but with higher growth in the higher emissions scenario (i.e. A2 scenario). In contrast, as far as super typhoons are concerned, the maximum intensity in the mature stage is relatively reinforced especially in the lower emission scenario (i.e. B1 scenario).

View full abstract

 Future change of wave climate depends on greenhouse gas emission/concentration scenarios and GCM models. Future projection of ocean wave climate was conducted by global climate models and a wave model, based on multi-model ensemble experiments. The winter wave heights in the Western North Pacific decrease under global warming corresponding to the West Pacific pattern (WP) change. This result is highly consistent among ensemble experiments.

View full abstract

 Recently, tropical cyclones (typhoon etc.) are getting more intense because of sea surface temperature rise due to the global warming. Hence, concern is increasing on storm surge and high waves which may cause severe damage to human lives and activities. Thus, many researchers have been trying to predict disaster potential by using the high resolution Atmospheric General Circulation Model (AGCM). The MRI-AGCM3.2S (the latest climate change prediction data) is one of the useful data sets for future prediction of stormy wave conditions. However, sea surface wind velocities of MRI-AGCM3.2S are much more intense compared with those of a long-term global atmospheric reanalysis (JRA-25). Therefore, it is important to calibrate the wind data set adequately for wave predictions by enhancing reliability of MRI-AGCM3.2S by introducing some corrections with utilizing JRA-25. In this study, first, the characteristics of the present and future data of MRI-AGCM3.2S and JRA-25 were investigated for the area of latitude 15~50°N, and longitude 115~150°E. Then, the cumulative distribution functions of wind velocity data for present climate inMRI-AGCM3.2S and JRA-25 as well as future climate data inMRI-AGCM3.2S were compared for determining the correction coefficients between the two data sets for adequately estimating future wind conditions. As a result, it is found that the correction coefficients are to be changed by every latitude. By introducing the correction coefficients as a function of the latitude, the wind data set calibrated in this study are found to be able to predict reasonable wave height.

View full abstract

 Explosively developing cyclones are becoming one of the important factors affecting winter climate. In recent instances in December 2014, high waves induced by two successive explosive cyclones developed over the Japan Sea hit the wide area along Japanese coasts. In this study, both frequency and duration of explosive winter cyclones as well as wave height during the winter storms are shown to be on an increasing trend for this few years around Japan based on reanalysis and observed data. High waves accompanied by the explosive cyclones in 2014 are found to have completely different features in the wave direction and growth rate from high waves induced by a typical winter monsoon.

View full abstract

 The storm surge due to the December 2014 Nemuro cyclone was hindcast using the Delft-3D/SWAN combined hydrodynamic and wave model with Japan Meteorological Agency (JMA) Mesoscale Model (MSM) reanalysis data as the surface boundary condition. Wind and pressure fields near Nemuro from the JMA MSM reanalysis data set agree with data from AMEDAS weather stations in eastern Hokkaido. The storm surge model result matches published measurements of water level and inundation extent in the town. Via application of the BOSZ Boussinesq-type wave model, the excitation of infragravity motions nearshore by this storm were found to be insignificant, but wave runup does cause an increase in the extent of inundation compared to that due to the still water storm tide hindcast by the Delft-3D/SWAN model.
 To evaluate the possible effects of climate change, a hypothetical storm with 150% the intensity of the 2014 cyclone was also simulated. Though the concrete armor units protecting the town's infrastructure are strong enough to escape damage from the hypothetical storm's waves, they are not high enough to prevent waves from riding atop the storm surge into low-lying areas of the town proper and the harbor. These waves are large enough to wreck residential buildings and pose a threat to life as well as property. Coastal hazards at locations in the midlatitudes, such as Nemuro, need to be reassessed accounting for the predicted effects of climate change, and adaptation strategies formulated based on local conditions.

View full abstract

 We propose a quantitative evaluation method of overall tsunami risk that the entire facility group over a wide area holds. We considerably reduced the calculation cost for tsunami inundation depth by adopting the evaluation method using energy conservation law as compared with the evaluation method using nonlinear long wave equation. For financial institutions such as banks and insurance companies with contractors over a wide area and business companies with multiple their assets and facilities in various places, the proposed evaluation method in this study could be a useful approach to implement their risk-based management decisions for tsunami risk.

View full abstract

 The seasonal fluctuations of water current characteristics and energy potential in Tsugaru Strait were investigated through field observation and numerical simulation. Using an ADCP, time series of multilayer velocity were measured during 4 seasons. As a result, the flow of Tsugaru Starait in the direction of southeast accompanied by periodic variations is constructed by combining the southeastward residual current to the tidal current in the direction of northwest-southeast in winter-spring season. In the duration of summer and fall, the difference of direction between tide and residual current cause complicated flow characteristics.The ocean and tidal currents in this strait were analyzed using MITgcm. The energy potential distribution estimated from the analysis results indicates that the summer-fall season has highest energy throughout the year nevertheless energy density distribution shifts southeast direction in comparison with winter-spring season.

View full abstract

 It is an important factor for wave overtopping type wave power generation to throw up the wave which attacks highly with a front slope, and to obtain much volume of overtopping. As fundamental study of wave overtopping type wave power generation, this research changes wave height, a period, and the angle of a slope, and experiments in the wave runup height by the regular wave and an irregular wave, and it aims it at asking for the reflection coefficient by the angle of a slope, and the characteristics of the wave runup height. As a result, with regards to wave steepness or an Iribarren number, as for the reflection coefficient, it became clear that wave runup height is related to wave energy and an Iribarren number.

View full abstract

 Renewable energies as substitute energy of nuclear power get much attention in not only Japan but also the world. Authors focus on the wave energy and have developed a wave power generation system using a vertical slotted breakwater with watermills installed in the chamber. From view point of the practical realization, it is necessary to estimate electrical power obtained by the watermill and power generation cost with enough accuracy as possible as we can. In the previous work, authors developed the experimental formulation between rotation rate of watermill and velocity amplitude through a vertical slit of the breakwater. In this paper, effect of scale of laboratory experiment was investigated through a series of experiments in different scale. Based on the experimental results, the formulation was modified so that the power obtained from wave by a watermill may be obtained with enough accuracy.

View full abstract

 Water column in a half immersed cylinder resonates effectively when its natural period coincides with an incident wave period. This study applied the resonance phenomenon to a wave power generation system that was composed of a floating body in the cylinder and an electromagnetic induction component. Resonated water column forces the floating body to oscillate in the cylinder. A series of hydraulic experiment was conducted to investigate the characteristics of induced voltage that was generated by the floating body motion. It was confirmed that the induced voltage is proportional to the speed of floating body moving under the irregular waves. This study also discussed the effect of an air nozzle that was employed to control the floating body motion within an appropriate range.

View full abstract

 In order to carry out disaster reduction efficiently, it is important to know well the probability of the damage, it means the risk assessments due to disasters. Two types of method on tsunami risk assessments were compared for the Ibaraki prefecture coasts where not many tsunamis have arrived, one is using the logistic tree for probabilistic occasion, magnitude of landslips and so on, and the other is extreme statistics analysis from the tsunami records. The results of probabilistic inundation map, causality and damage of houses show that large uncertainly remains.

View full abstract

 To investigate the validity of the design tsunami in Kamaishi area, we conducted probabilistic tsunami hazard analysis (PTHA). We assumed 207 tsunami scenarios to construct tsunami hazard carve. As results, the design tsunami in Kamaishi area (T.P. 6.1 m) deserve a tsunami apploximately once per 450 years, which is quarter as frequent as Level 1 tsunami. Based on the tsunami hazard carve, we further made tsunami risk map classifyed by tsunami occurrence frequency. This map is available to estimate risk ranking of tsunami evacuation sites or disaster prevention facilities considering several tsunami scenarios.

View full abstract

 46 percent of the nursery schools in Tokushima Prefecture are located in a tsunami inundation area. We carried out an interview survey and disaster prevention advice on earthquake and tsunami countermeasures at 76 nursery schools in coastal area. After one year, we conducted a questionnaire survey to examine the improved situation of disaster prevention measures. The technical guidance in a interview survey was effective in reducing an average evacuation distance and an average evacuation time. The disaster action card recommend by us was created in about 20 percent of the nursery schools and was effective for faster evacuation.

View full abstract

 The effectiveness of coastal dikes was quantitatively assessed by simulating 43 cases of tsunami inundations. The duration of a tsunami overflow that a coastal dike can withstand was asumed to be the persistence of the dike against a tsunami. Three types of tsunami height, six levels of dike endurance, and 5 to 7 types of dike collapse probabilities were selected as parameters for investigating the sensitivity of the dike endurance to risk reduction. The area of inundation and the available evacuation time were selected as the indexes representing the expected reduction in risk; these parameters were compared between cases. The results showed a clear relationship between the persistence levels of a dike and the degrees of risk reduction. The effect of enhancing the persistence of a dike to reduce damage is high when the height of a tsunami is low. The road and the bank also exhibit a synergistic disaster reduction effect when they are constructed landward as secoundary dike-like structures. These results are the first quantitative evidence supporting the necessity of reinforcing coastal constructed in the Tohoku district.

View full abstract

 The Kii Peninsula is the largest and the southernmost peninsula on the island of Honshu in Japan. It faces a severe risk of Nankai megathrust earthquake which will be occurred in near future. This peninsula is well known for the Shinto sanctuary, such as the Grand Shrine of Ise and there are many shrines in the vicinity of coastal area. In this study, in order to examine the conversion of the shrines into evacuation sites, using the spatial information of shrines and the results of numerical simulation on tsunami damage, tsunami suffered risk of each shrine was examined. Moreover, the difference of damage risks of each enshrined god was clarified.

View full abstract

 Some people in buildings escape outdoors in order to protect themselves against the strong shake of the earthquake. The authors focused on this behavior and revealed its relationship to starting the quick tsunami evacuation. In this research, the 2014 Off Iquique Earthquake and Tsunami was selected to be the site of interest. To capture the behaviors of customers and staff in Mall ZOFRI, which is the large shopping mall located in Iquique, Chile, we conducted the interview survey, analyzed the security camera footage, and simulated the situation just after the strong shake of the earthquake. This study revealed that escaping outdoors helps in quick tsunami evacuation.

View full abstract

 A crowd evacuation simulation was developed for the evaluation of the human damage risk by tsunami. Concretely the hybrid model which is composed of the potential model and distinct element model was improved with the introduction of the use of GIS data and the consideration of complex evacuation behavior for the solution of real problems. The present model was applied for the tsunami evacuation simulation in the real village and the usavility was confirmed. For the consideration of the characteristics of evacuation routes, the result by the present model was different from the empirical model. The time delay to start evacuation was determined from the questionnaire result and the simulation turnend out to be similar to the actual evacuation situation. Finally the disaster mitigation effect with the combination of the hard measures and soft measures was disscussed.

View full abstract

 Evaluation of ripple effects of 10-years-disaster-prevention-education in Tsuda Junior High School on a disaster-prevention activity of local citizen was conducted by a questionnaire survey. Moreover, educational effect of new educational program of preliminary reconstruction and urban development plan was conducted by participant observation. As a result, 90% of local citizen recognized the educational activity and the activity demonstrated an effect of promoting citizen's preparation for earthquake and Tsunami. According to the cross tabulation, it was found that majour factors of the increasing recognition of the educational activity were their children's attendance experience with the educational program and relationship to own disaster prevention activities. Student's plan of preliminary reconstruction and urban development plan became factual by learning past student's plans and its problem points.

View full abstract

 On 11 March 2011, 20% of residents in Noda villeage in Iwate, Japan evacuated against tsunami. As other regions in Japan, about 60% of evacuee used car to evacuate in Noda and delay in traffic is reported. Car is valid to transport person who need care to ecvacuate or to evacuate to distant area. However evacuation by cars may cause delay in traffic and disturb pedestrian evacuation. In this study, we analize evacuation behavior in Noda villeage in the Great East Japan Earthquake to reveal reason for delay of departure time and wheaher use of cars in evacuation caused traffic congention. Conclusion of this study is that central reason for evacuation by car and delay of departure time is to bring or rescue family members or acquaintances, and in Noda village, there wasn't fatal traffic jam araound center of town arised by evacuations by car.

View full abstract

 General disaster evacuation training for elementary and middle schools designate the assumption of disaster occurrences while in class time and participants are only students and teachers. However, in actual evacuation, disaster occurance is independent of time and multi stakeholder are involved. This paper is to explain a evacuation training method which all schools, residents and local government office participate in a fixed municipality. The results were the followings: 1) Middle school students and the higher class students of elementary schools played important roles that are coordinate younger student and safety confirmation themselves. 2) The time required for safety confirmation of schools related to student size without regard for types of evacuation. report and aggregate information. 3) Schools, resident organizations and the government office are gradually catching on mutual circumstances with this planning and training as a start.

View full abstract

 In the case of tsunami evacuation, people to escape are not only existing residents and workers but also visitors such as tourists and business travelers in estimated tsunami inundation area. This paper aims to clear behavioral characteristic of visitor on tsunami evacuation and to discuss effects of evacuation guidance sign and verbal instruction with an experiment in the central area of Ishinomaki city. The results were the followings: 1) Tsunami evacuation spot as a destination point should be selected on the basis of simple route from starting point better than shortest distance. 2) Tsunami evacuation guidance sign does not always effectively navigate a visitor. 3) It is important that verbal instructions is not used “local spoken term” such as landmark name called in only the area, not official and standard name.

View full abstract

 In order to accurately predict evacuation behaviors caused by a tsunami, evacuation simulation taking into consideration vehicle-pedestrian interaction and detour routing to the shelters has been developed and applied to the case of Kesennuma City where detail information on the evacuation at the 2011 Tohoku earthquake and tsunami are available from fact-finding investigation by the Japanese MLIT and Kesennuma Municipal Government. The simulation well reproduces evacuation traffic flow as reported from MLIT and Kesennuma Municipal Government. The shortest path routes adopted in previous studies are unable to well reproduce the traffic flow, therefore we revised the method by changing potential value depending on the importance. The study demonstrates the existence of the effects of vehicle-pedestrian interaction. The area where influences were observed in the simulation is same as area where the risk of car-pedestrian interaction was mentioned by evacuees. The evacuee population in some shelters in the simulation well reproduces the trend of the real number of evacuees reported by the Kesennuma Municipal Government.

View full abstract

 To date, coastal economic values have been forcused on either natural ecosystem or artificial constructions on coastal area. In this paper, we developed a quatitative method to evaluate coastal protect function and port function by modifying the Ocean Health Index. This method includes not only the present conditions but also the near future conditions. The coastal protect function is evaluated reduction of wave propagation and inundation prevention. The port function is evaluated by the depth of shoreline in light of two factors: with or without berthing facility and the distance from shoreline to navigable depth for a small fish boats. We applied the method to four tidal flats in Tokyo Bay to spatially and comprehensively quatify the coastal protect function and the port function.

View full abstract

 The AIS (Automatic Identification System) data on ships in Kashima Port was analyzed to investigate movement characteristics of the ships transported by the 2011 Tohoku tsunami and their collision damage to port facilities. The main results are as follows: 1) Bigger ships can cause damage to the facilities many times even if longer time passed from the earthquake occurrence. 2) In the most inner part of the channel-shaped port, water particle velocity which could be reduced by the reflected tsunami shortened the length of ship's movement by the tsunami and reduced ship's speed when colliding with a port facility, resulting in reduction of severe collision damage to the facility. 3) Significant drift movement was observed even in a channel-shaped port with oblique, transverse and rotational motions, owing to complex tsunami flow and various ship maneuvering.

View full abstract

 A field survey was carried out from August 2011 to November 2013 in Miyagi prefecture to evaluate the salt removal performance of a rice paddy due to rainfall after tsunami attack.
 It was found that (1) Chlorine ion, Cl^-, concentration near the soil surface was reached several to hundred times as much as the allowable Cl^-concentration of rice planting in August 2011. Consequently, Cl^-concentration in the soil up to 100mm below the soil surface remarkably decreased with time. Two years after the tsunami attack, the time variation of Cl^-concentration became small in the whole root zone, (2) In the paddy soil attacked by the tsunami with an inundation height, H, of 3.5m or less, it took one year after tsunami attack before total Cl^-concentration in the root zone, ∑Cl^-decreased to the allowable ∑Cl^-of rice planting, ∑Cl^-_al, (3) Relationships between H and elapsed days reached ∑Cl^-_al, Day_al, and cumulative rainfall depth for Day_al can be expressed by equations (6) and (9), respectively.

View full abstract

 School buildings are important facilities due to their capacity as evacuation shelters. In 2013, Typhoon Haiyan and its storm surge damaged most schools in the affected area because they were one story structures built using weak material. Therefore, school buildings used as evacuation shelters did not function effectively. Thus, more studies on vulnerability of school buildings to coastal disasters in terms of damage and use as evacuation shelters are needed. A field survey was conducted from 26 May to 2 June 2014 to observe damage to school buildings in Tacloban, Palo and Tanauan. One-third of the schools were damaged by a combination of both typhoon winds and storm surge, and the rest by typhoon winds only. Detailed damage data on 166 school buildings in 39 school districts was directly obtained from Tananuan. The data for each building contain economic damage, building area and percentage damage to building structure, namely roofing, roof frame, ceiling, wall, window and door. Economic damage ratio is calculated as the ratio of loss to building area. The data was then overlaid on the storm surge inundation map created by field surveys and the distance of each building from the sea measured. Numerical simulations were applied to obtain the maximum storm surge flow depth and flow velocity, with wind speed derived from JMA data and a parametric hurricane model. The percentage of damage, distance from the sea and other disaster-related parameters were plotted in order to compare damage between the buildings inside and outside the storm surge inundation zone. Results show the damage ratio to walls is 0.3-1.0 in the storm surge inundation zone and decreases to about 0.5 or less for buildings outside the inundation zone. The average loss ratio is about 5,500 Philippine Peso (PhP) per m² due to the strong wind speed of 50-60 m/s.

View full abstract

 This study aims to investigate the mechanisms of observed inundation characteristics around the San Pedro bay induced by Typhoon Haiyan. Numerical analysis was first carried out to overview the characteristics of storm surge and stormy waves. It was found through the analysis that strong anti-clockwise circulating current was developed in the San Pedro bay. Laboratory experiment was then conducted to investigate the interactions of strong current and waves. It was found through the experiment that the strong current dramatically changes the dissipations of stormy waves and this feature may reasonably explain the observed inundation characteristics especially around the mouth of San Pedro bay.

View full abstract

 On Nha Trang Coast, in southern of Vietnam, investigation of shoreline change using video-camera technique has been carried out over the period of about one and a half year. Thus, data of shoreline change was obtained two times for the northeast monsoon period and two times for the non-monsoon period. Images on plane coordinate system, which are projected from oblique images of the video-camera system, are utilized to evaluate shoreline variation. During the northeast monsoon period, longshore sediment transport from north to south is dominant; as a result, that causes erosion of sandy beach in the north end area of Nha Trang Coast. Recovery process of shoreline in this area is observed in the nonmonsoon period. In addition, the variation of shoreline is analyzed to obtain longshore sediment transport rate. Characteristics of waves are greatly different between the northeast monsoon period and the nonmonsoon period; hence, it is necessary to change value of depth of closure (D_C) for corresponded season. This study determined seasonal variation of depth of closure as well as an ordinary method to obtain a constant value of depth of closure has been also utilized; the difference is clarified.

View full abstract

 The rip current occurs at the wave breaking area near the beach, and the accident that is related to the rip current occurs every year in the world. Some generation mechanisms of the rip current are known. For example, the rip current occurs at the sand beach that has the cusp topography, and occurs near the structures such as the groins. In Niigata, there is not many large beach, and ordinary the beach is enclosed or semi-enclosed the groins those were built to protect from the coastal erosion.
 This study tried to comprehend the generation mechanism of rhe rip current at the enclosed and the semi-enclosed beach by the groins. Firstly, this study did field survey and comprehended the large scale and velocity of rip current. In this method, the rip current was pigmented by the sea water colorant, and the pigmented current was observed by the velocity meter and recorded as the aerial photography by the UAV. Secondary, this study reproduced the rip current by the numerical simulation. The result was compared with the field observation data.

View full abstract

 Coastal managers and swimming beach managers are supposed to pay enough attention to safe utilization of recreational beaches. To ensure the safe utilization of a beach, it is better to detect a rip current location and special size, and use such information for public awareness program. Visualization such as an aerial photograph is probably informative for the purpose; therefore an inexpensive multi-copter system is applied to monitor a nearshore bathymetry, nearshore current especially a rip current in Uchinada beach, Kanazawa City, Ishikawa Prefecture, Japan in September, 2014. Dye and GPS float buoys are also applied to obtain qualitative and quantitative date of rip current. As a results, it is shown that a rip current visualization by a multi-copter system and dye are the most efficient and inexpensive technics for a rip current detection, except windy and rainy conditions. Video images by the system also can be applicable to study generation of nearshore current system.

View full abstract

 Dynamical downscaling experiment of JRA55 for Typhoon Vera (Isewan Typhoon) using WRF was carried out. At First, the reproducivilities of five global reanalysis data for Typhoon Vera were compered, and it was shown that JRA55 has highest quality. There are some papers of the dynamic downscaling method for storm surge hindcast. In this study, domain size and resolution of the coarse domain were considered. The coarse domain size influences the typhoon route and central pressure, and large domain estimates large error of typhoon route and stronge typhoon. Threshold is whether the coarse domain fully includes the area of wind speed more than 15 m/s around the typhoon. On the other hand, the resolution of the coarse domain doesn't affect the typhoon route, and affect the typhoon strength.

View full abstract

 The real-time tsunami forecast using the database or real-time simulation was tried to develop before 2011 Tohoku earthquake. However, the method using a database and the real-time simulation are sub-ject to improvement of accuracy and large-scale calculation facilities respectively. After 2011 Tohoku earthquake, a new study proposed a real-time estimation of tsunami source by using the crustal move-ment and GPS tsunami observed data for tsunami forecast, which will provide us with the tsunami initial condition with higher accuracy in real time. Therefore we combine the database with a new study in real time to estimate a tsunami inundation in a short time even by PC computer. In this study, we compared this forecast with the tsunami inundation area caused by 2011 Tohoku earthquake. As a result, this method could provide information on inundation area for evacuation within 10 minutes after an earthquake occurrence.

View full abstract

 The 2011 Great East Japan Tsunami on 11 March 2011 induced extensive erosion along the Pacific coast. Significantly eroded Yamamoto Coast was one of the few coasts where coastal topography data was obtained from before to after the tsunami. To clarify the erosion and recovery processes from before to after the tsunami is important for coastal management; however, it still remains unclear because of lack of information at most of the eroded coasts. The purpose of this study is to develop a method to extract the coastal profiles during recovery process after the tsunami using ground-penetrating radar (GPR) without coastal topography data. GPR can image subsurface structure by radiating electromagnetic waves in the ground and receiving the reflected signals. By scanning GPR on the ground, we can obtain the imageof subsurface structures which reflect signals. We carried out field survey using GPR in Yamamoto coast eroded by 2011 tsunami and recovered to a degrees. We measured GPR on 4 survey lines set normal to shoreline, and sampled deposits along the survey lines. We read the points of the shoreline from aerial photos and extracted reflecting planes, estimated the ground forms when the photos were taken, from the image in the ground. As a result of analysis, the slopes of coastal profiles during the recovery were approximately 0.06-0.13. It is demonstrated that this method using the GPR is a very useful tool to understand the recovery processes after the tsunami at the coasts where measurement data does not exist.

View full abstract

 The applicability of image analysis using a UAV mounted digital camera to inspect damage of coastal protection facilities deteriorated by aging was examined. The image pictures were taken from an altitude of 25 m to be 4 mm resolution, and damage of facilities was detected on the three-dimensional model generated by an image processing method: Structure from Motion (SfM). As a result, cracks of 2-5 mm width on the concrete structures could be detected from the image pictures, and the deflection of the concrete dike could be estimated at 2 cm accuracy by the three-dimensional model analyses. To quantify the accuracy of the method affected by the conditions of imaging and UAV flight is required to be valid and efficient method.

View full abstract

 An object-oriented method to estimate building damage is developed using Advanced Land Observing Satellite/Phased Array Type L-band Synthetic Aperture Radar (PALSAR) data from Japan Aerospace Agency (JAXA), by focusing on the 2011 Tohoku earthquake and tsunami event. The building damage was estimated by applying the developed damage function showing a relationship between the correlation coefficient values of pre- and post-event SAR data and the damage ratio of washed-away buildings. The result was verified by the actual number of washed-away buildings, and offered the good accuracy with pearson's correlation coefficient of 0.97.

View full abstract

 A building damage function was developed using very high-resolution synthetic aperture radar (VHR SAR) images and post-event building damage data after the 2013 Super Typhoon Haiyan, obtained from Tacloban city, the Philippines. Structural damage caused by the typhoon was analyzed focusing on changes in the radar footprint signatures of affected buildings. These changes are classified using a phase-based coefficient calculated from pre- and post-event COSMO-SkyMed images. The damage function is expressed as the damage ratio of structures with regard to the phase-based coefficient. The application of the estimated damage function in Tacloban city shows that from a group of structures with a POC coefficient of 0.2 or less, at least half of them are expected to be damaged.

View full abstract

 Satellite remote sensing methods of ocean color was developed based on the results of field observations in an eutrophication water area, Tokyo bay. From field observations, it was found that absorption coefficients of phytoplankton and detritus were related to Chl-a and that of color dissolved organic matter (CDOM) to salinity. On the basis of these optical properties, bio-optical model was developed and it showed that aph spectrum around 550nm increased when red tides occurred by the developed model. In addition, using these findings, we developed three parameters, Chl-a estimation model which assimilates observation results, aCDOM estimation model which uses two bands, blue region and red region and ad estimation model, modification of the Quasi-Analytical Algorithm. Furthermore temperature estimation accuracy by MODIS sensor was validated. Thus, it became possible to estimate each of four parameters spatially and simultaneously.

View full abstract

 Extracting ocean current patterns is important to predict the advection and diffusion process of thermal water from a power plant, and accidental release of oil and contaminated water. Ocean radar is one of the most powerful tools for measuring surface currents, with high spatial and temporal resolution of the two-dimensional flow field over a large coastal area without depending on the weather conditions. Self-organizing map (SOM) analysis is an efficient method for feature extraction and classification of nonlinear large data sets such as radar observation. In this study, we conducted batch-learning SOM analysis of ocean radar data with the aim of finding out the main surface current patterns in eastern Wakasa Bay. The Wakasa Bay area is the site of many power plants, but it is difficult to predict the surface current patterns because of small tide currents. The analysis focused on daily mean current vectors, and the SOM unit weights were initialized using results of empirical orthogonal function analysis. The SOM results well captured the characteristic features of current patterns associated with coastline topography and local wind. We also applied SOM to flow patterns at the entrance of the Bay and related these patterns to surface current patterns in eastern Wakasa Bay. Our results show that SOM analysis of the ocean radar observation can detect the patterns of coastal current without mooring current meters, and is potentially useful for assessing the environmental impact.

View full abstract

 Atomospheric CO₂ absorption by coastal ecosystmes has been recently focused as a promising option for the future climate change mitigation initiatives. The presice measurment of the CO₂ absorption is necessary for the quantitative evaluation of the option. However, the existing method requires too much efforts and costs for the management of long-term and wide-range data, In this study, we focused to the eddy covariance method, which enables to auto-measurment, and developed the data management (Rejection of cross sensivitity effect and outlier wind data, High-Pass filtering, and evaluation of relative effect of WPL correction) based on a long-term coastal measurement data.

View full abstract