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.- The highest storm tide noted in historical accounts was produced by the 1899 Cyclone Mahina, estimated at almost 44 ft (13 metres) at Bathurst Bay, Australia, but research published in 2000 saw the majority of this was likely wave run-up, due to the steep coastal topography. In the United States, one of the greatest recorded storm surges was generated by 2005's Hurricane Katrina, which produced a maximum storm surge of more than 25 ft (8 metres) in the communities of Waveland (41.5 ft), Bay St. Louis (38 ft), Diamondhead (30 ft) and Pass Christian (35 ft) in Mississippi. Another record storm surge occurred in this same area from Hurricane Camille in August 1969, with the highest storm tide of record noted from a high water mark as 24.6 ft (7.5 m), also found in Pass Christian (the back side of St. Louis Bay got up to 35 ft). A high storm surge occurred in New York City from Hurricane Sandy in October 2012, with a high tide of 14 ft (4.2 m).III. Characteristics: 1. Factors Impacting SurgeStorm 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. Storm surge is produced by water being pushed toward the shore by the force of the winds moving cyclonically (counter clockwise) around the storm. Image credit: UCAR/The COMET Program.
The maximum potential storm surge for a particular location depends on a number of different factors. Storm surge is a very complex phenomenon beca
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