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Emergency response service of scientific data for Extremely Strong Cyclone “MOCHA” disaster in Bay of Bengal
Since May 13th, the waters near Cox's Bazar Port in southeast coast of Bangladesh have gradually become rough. Since midnight on May 13th, MOCHA has had maximum sustained winds of 180 kilometers per hour and gusts of 200 kilometers per hour in a 74 km area extending outward from the center. Strong cyclone storm "MOCHA" in the Bay of Bengal has strengthened into a strong cyclone storm in the morning of May 13th (Beijing time, the same below). At 8:00, its center was located in the middle sea of the Bay of Bengal about 680 kilometers south by west direction of Sittwe, Myanmar. The maximum wind near the center was 15 force (50 m/s, equivalent to strong typhoon level in China). By the afternoon of 14 local time, MOCHA had passed through and gradually moved away from the coastal area between Cox's Bazar and northern Myanmar, posing no major tidal wave threat as of 13:00. MOCHA had maximum sustained winds of 160 kilometers per hour within 74 kilometers of the storm's center, with gusts likely to increase to 180 kilometers per hour. The National Cryosphere Desert Data Center (NCDC) for Glaciology and Permafrost Desert collects and prepares basic geographic data, satellite remote sensing data, population data, topographic data and other emergency response scientific data based on disaster situations.The "Emergency response service of scientific data for Extremely Strong Cyclone “MOCHA” disaster in Bay of Bengal" system has been released, which provides data visualization, interoperation and data download capabilities.For use by relevant emergency, rescue and research departments. The subsequent NCDC will continue to further collect and sort out various data resources in the gradually release them through the data center platform for the use of relevant emergency, rescue and research departments. Service Website:
New Models
A large number of reservoir inflow with preserved data, spillway discharge and discharge of breach ditch (unstable flow with sediment transport capacity) formed along erosion are comprehensively applied in the model. It is assumed that the slope ratio at the bottom of the breach is basically the same as that at the downstream of the dam. The development of breach ditch depends on the material properties of dam body (D50 size, unit weight, friction angle, bond strength). The model takes into account the following possible complexities: 1) the material properties of the dam core and the outside of the dam are different; 2) before the real breach caused by overtopping flow is formed, the erosion ditch along the downstream slope surface of the dam is determined; 3) the downstream slope of the dam may be covered with grass or contain materials larger than the external components of the dam; 4) the shear strength and cohesive force are exceeded The results show that more than one sudden structural collapse mechanism is enlarged due to the hydrostatic pressure; 5) the width of the breach obtained from the slope stability theory is enlarged; 6) the free surface breach flow is developed by piping, which causes the collapse; and 7) the non cohesive material (gravel) or cohesive material (clay) may be carried away by erosion. The discharge water level hydrograph is obtained by time step iterative method, which can be completed in only a few seconds on a main computer. The model is not constrained by numerical stability and convergence stability.