Influence of climate change on storm surges in the Ariake sea

The influence of climate change on storm surges in the Ariake Sea was evaluated using the stochastic\ud typhoon model. The Ariake Sea is located in the middle of Kyushu Island, Japan and has been attacked by severe\ud typhoons many times. There are many lowland coastal farmlands along the coastline of the Ariake Sea as a result of\ud many reclamation projects since ancient times. These coastal farmlands are at risk of even more severe storm surges due\ud to typhoons caused by climate change. The deviations of tides due to storm surges were simulated by an experimental\ud typhoon model employing the Myers model. The stochastic typhoon model generated the tracks and attributes of\ud typhoons over the next 2,000 years. Meanwhile, the tracks of typhoons in the case of the climate after climate change\ud were generated by shifting the start points of typhoons 0.9 degrees further north and 1.9 degrees further east. The\ud number of typhoons after climate change was set to 0.79 times that of typhoons in the present climate. These changes in\ud the tracks and number of typhoons in the future were decided according to the results of numerical simulations of\ud climate change using the AGCM model based on the A1B scenario. The non-exceedance probabilities of the yearmaximum\ud anomaly rise were compared to evaluate the change due to climate change. The simulation suggested that the\ud height of the year-maximum anomaly rise due to storm surges in the future climate will be similar to or slightly lower\ud than the present height

Damages caused by 3/11 Great East Japan earthquake on coastal drainage pumping stations along Sendai bay

On March 11, 2011, a tsunami struck low-lying land along Sendai Bay, where no tsunami had hit in the past 200 years. These coastal lowlands were equipped with drainage pumping stations for paddy areas, but the pumping stations were destroyed by the tsunami, thus preventing drainage of the sea water inundation.There are two kinds of pumps, motor and diesel pumps. Even diesel pumps need electricity to start up and control their power. If a pump is inundated by salt water, all electric parts will be short-circuited. Although the diesel mechanisms can be reused after being washed by fresh water, the electric parts of both types of pump must be replaced. The switchboard for the pumps must also be replaced. If damages are caused only by salt inundation, the electric parts of both types of pump must be replaced. Temporary recovery was done by manually controlling the pumps because the automatic pump control system was difficult to restore. The mean recovery time was one month for electric pumps and two months for diesel pumps. For pumps that were broken by external force, quick recovery was abandoned.Past studies on tsunami have shown that concrete structures are strong enough to withstand tsunami surges. In the present study, a few concrete pumping stations located near the coast were damaged. The damages to buildings were mainly governed by the type of material and location on the coast. At some pumping stations, the tank for desorption prevented external forces from acting on the buildings.These results show that the tsunami safety of drainage pumping stations could be improved by increasing the resistance to salt inundation and appropriately locating the tank for desorption

Impurity Effects on Quantum Depinning of Commensurate Charge Density Waves

We investigate quantum depinning of the one-dimensional (1D) commensurate charge-density wave (CDW) in the presence of one impurity theoretically. Quantum tunneling rate below but close to the threshold field is calculated at absolute zero temperature by use of the phase Hamiltonian within the WKB approximation. We show that the impurity can induce localized fluctuation and enhance the quantum depinning. The electric field dependence of the tunneling rate in the presence of the impurity is different from that in its absence.Comment: 14 pages with 13 figures. Submitted to J. Phys. Soc. Jp

Numerical computations of facetted pattern formation in snow crystal growth

Facetted growth of snow crystals leads to a rich diversity of forms, and exhibits a remarkable sixfold symmetry. Snow crystal structures result from diffusion limited crystal growth in the presence of anisotropic surface energy and anisotropic attachment kinetics. It is by now well understood that the morphological stability of ice crystals strongly depends on supersaturation, crystal size and temperature. Until very recently it was very difficult to perform numerical simulations of this highly anisotropic crystal growth. In particular, obtaining facet growth in combination with dendritic branching is a challenging task. We present numerical simulations of snow crystal growth in two and three space dimensions using a new computational method recently introduced by the authors. We present both qualitative and quantitative computations. In particular, a linear relationship between tip velocity and supersaturation is observed. The computations also suggest that surface energy effects, although small, have a larger effect on crystal growth than previously expected. We compute solid plates, solid prisms, hollow columns, needles, dendrites, capped columns and scrolls on plates. Although all these forms appear in nature, most of these forms are computed here for the first time in numerical simulations for a continuum model.Comment: 12 pages, 28 figure

Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments

In the overlap region, for the normal and inverted hierarchies, of the neutrino-antineutrino bi-probability space for $\nu_\mu \to \nu_e$ appearance, we derive a simple identity between the solutions in the ($\sin^2 2\theta_{13}$, $\sin \delta$) plane for the different hierarchies. The parameter $\sin^2 2\theta_{13}$ sets the scale of the $\nu_\mu \to \nu_e$ appearance probabilities at the atmospheric $\delta m^2_{atm} \approx 2.4 \times 10^{-3}$ eV$^2$ whereas $\sin \delta$ controls the amount of CP violation in the lepton sector. The identity between the solutions is that the difference in the values of $\sin \delta$ for the two hierarchies equals twice the value of $\sqrt{\sin^2 2\theta_{13}}$ divided by the {\it critical} value of $\sqrt{\sin^2 2\theta_{13}}$. We apply this identity to the two proposed long baseline experiments, T2K and NO$\nu$A, and we show how it can be used to provide a simple understanding of when and why fake solutions are excluded when two or more experiments are combined. The identity demonstrates the true complimentarity of T2K and NO$\nu$A.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of Physics, ``Focus on Neutrino Physics'' issu