12:00 PM - 12:15 PM
[AOS15-06] Case study of storm surges by Bhola Cyclone in 1970
Keywords: storm surges, tropical cyclone, simulation
Storm surges by Bhola cyclone in 1970 were numerically simulated and analyzed. Bhola cyclone is well known as the deadliest case in recent world history, the death toll in East Pakistan (current Bangladesh) is estimated 300,000 – 500,000 which was mainly killed by storm surges. However, its detailed behavior was not clear although it happened about 50 years ago and some reliable data exist. It could be meaningful to simulate the worst case with a recent storm surge model and analyze the mechanism in detail.
Since no reanalysis results adequately resolve the cyclone, we started with estimating cyclone conditions for forcing in simulations. Some parameters were empirically assumed, by referring recent cyclone conditions and simulated storm surges. Storm surge simulations were finally conducted with the determined cyclone conditions.
Calculated results indicate storm tides of 3-7m (storm surge of 2-4m) which is really large values there, and wide areas were inundated in the southern coast. Although simulations were conducted with some assumptions, the results seem to be fairly compared with damage records, and looks reasonable. The reason for devastating disaster could be explained with a few conditions. One is the cyclone course because the cyclone passed through almost whole coasts with kept intensity. The other reason will be coincidence of timing with high tide of spring tide.
Since no reanalysis results adequately resolve the cyclone, we started with estimating cyclone conditions for forcing in simulations. Some parameters were empirically assumed, by referring recent cyclone conditions and simulated storm surges. Storm surge simulations were finally conducted with the determined cyclone conditions.
Calculated results indicate storm tides of 3-7m (storm surge of 2-4m) which is really large values there, and wide areas were inundated in the southern coast. Although simulations were conducted with some assumptions, the results seem to be fairly compared with damage records, and looks reasonable. The reason for devastating disaster could be explained with a few conditions. One is the cyclone course because the cyclone passed through almost whole coasts with kept intensity. The other reason will be coincidence of timing with high tide of spring tide.