STORM SURGEName: Lê Thị Tuyết MaiClass: K58-Khí tượng họcContentsI. IntroductionII. Historic storm surgesIII. CharacteristicsIV. The influence and impact:V. OBSERVE, MEASURE AND FORECAST OF THE INFUENCE:1. INTRODUCTION: Concept:- A storm surge is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low pressure weather systems (such as tropical cyclones and strong extratropical cyclones), the severity of which is affected by the shallowness and orientation of the water body relative to storm path, and the timing of tides. Most casualties during tropical cyclones occur as the result of storm surges.- Storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides. Storm surge should not be confused with storm tide, which is defined as the water level rise due to the combination of storm surge and the astronomical tide. This rise in water level can cause extreme flooding in coastal areas particularly when storm surge coincides with normal high tide, resulting in storm tides reaching up to 20 feet or more in some cases.- The two main meteorological factors contributing to a storm surge are a long fetch of winds spiraling inward toward the storm, and a low-pressure-induced dome of water drawn up under and trailing the storm's center.II. Historic storm surges Total destruction of the Bolivar Peninsula (Texas) by Hurricane Ike's storm surge in 2008- The deadliest storm surge on record was the 1970 Bhola cyclone, which killed up to 500,000 people in the area of the Bay of Bengal. The low-lying coast of the Bay of Bengal is particularly vulnerable to surges caused by tropical cyclones. The deadliest storm surge in the twenty-first century was caused by the Cyclone Nargis, which killed more than 138,000 people in Myanmar in May 2008. The next deadliest in this century was caused by the Typhoon Haiyan (Yolanda), which killed more than 6,000 people in the central Philippines in 2013 and resulted in economic losses estimated at $14 billion (USD). - The Galveston Hurricane of 1900, a Category 4 hurricane that struck Galveston, Texas, drove a devastating surge ashore; between 6,000 and 12,000 lives were lost, making it the deadliest natural disaster ever to strike the United States.-Các triều bão cao nhất ghi nhận trong lịch sử các tài khoản được sản xuất bởi 1899 Cyclone Mahina, ước tính đạt gần 44 ft (13 mét) tại Bathurst Bay, Australia, nhưng nghiên cứu xuất bản năm 2000 đã thấy đa số này là thời gian chuẩn bị có khả năng làn sóng do địa hình dốc ven biển. Ở Hoa Kỳ, một trong những lớn nhất được ghi nhận cơn bão dâng được tạo ra bởi 2005 của cơn bão Katrina, nơi sản sinh ra một tối đa cơn bão tăng hơn 25 ft (8 m) trong cộng đồng Waveland (41,5 ft), Bay St. Louis (38 ft), Diamondhead (30 ft) và vượt qua Thiên Chúa giáo (35 ft) ở Mississippi. Một cơn bão kỷ lục tăng đã xảy ra trong cùng một khu vực này từ Hurricane Camille vào tháng 8 năm 1969, với thủy triều bão cao nhất của kỷ lục ghi nhận từ một high water mark là 24,6 ft (7.5 m), cũng được tìm thấy trong vượt qua Thiên Chúa giáo (mặt sau của Bay St. Louis đã lên đến 35 ft). Một sự đột biến cao bão xảy ra tại thành phố New York từ cơn bão Sandy trong tháng 10 năm 2012, với thủy triều cao của 14 ft (4.2 m).III. đặc điểm: 1. các yếu tố tác động đến sự đột biếnStorm surge and coastal flooding depend on a number of factors. These factors include the intensity of a storm, its size, translational speed, angle of approach to the coast, landfall location, and the bottom slope at that location. It is well accepted that the most influential factor in storm surge generation is the central pressure deficit, which controls the intensity of a hurricane, i.e., wind velocity and stress over the ocean surface and inverse barometric effects. The influence of the other factors, such as the storm size (measured by the radius from the center of a hurricane to the location of maximum wind speed), the translational speed, and the angle of approach, became apparent after Hurricane Katrina's catastrophic storm surge in 2005 (Hurricane Katrina was a Category 3 storm). Lower atmospheric pressure (faster wind speeds) and larger storms create a greater storm surge potential. Slower and larger but weaker hurricanes (e.g., Category 3 storms such as Katrina) cause much higher storm surge and flooding (even to inland areas) when compared to faster and small but more intense hurricanes (e.g., Hurricane Charley in 2004). Storms that make a perpendicular approach toward the coastline will also cause a greater storm surge, whereas those that travel parallel to the coastline will have a reduced storm surge.
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