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A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by names such as hurricane typhoon or tropical cyclone. Within Delft3D-FLOW time-series for space varying wind velocity components (east-west and south-north) and atmospheric pressure on a Spiderweb spiderweb grid can be used to simulate the impact of such an event. For more information about these possibilities one is referred to the Delft3D-FLOW manual.
Background
A fundamental part of cyclone modelling are the relationships you apply to generate your spiderweb. Often you only have information about the track and a maximum wind speed (Vmax). However, to generate a spiderweb you also need to have a maximum pressure drop (Pc), radius of maximum wind (Rmax) and a wind profile. On top of that there are constants involved with the generation of the wind and pressure fields, for example the environmental pressure, inflow angle and the ratio between the maximum wind for 1 minute and 10 mintues.
- Wind profile: parametric radial profiles of hurricane winds form the basis of current approaches to assessing wind return periods and the development of engineering standards in hurricane-prone regions. Holland (2010) revised the Holland (1980) parametric approach by applying information readily available from hurricane archives or in hurricane warning information.
- Vmax-Pc relation: A technique for relating central pressure and maximum winds in tropical cyclones. Default in Dashboard is Holland (2008).
- Rmax relation: The RMW plays an important role in hurricane risk prediction. There are multiple relationship implemented in Delft Dashboard. Often the radius of maximum winds (RMW or Rmax) is related to the pressure drop and latitude. One of such relations is Vickery and Waldhera (2008).
Besides these relationship we describe the hurricane in a spiderweb with a limited amount of directional bins, radial bins and a maximum radius.
Usage of the toolbox
The Tropical Cyclone toolbox makes it possible to computes wind field and pressure drop generated by a cyclone. All it takes are basically four steps
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