A WRF-based engineering wind field model for tropical cyclones and its applications

Strong winds induced by tropical cyclones (TCs) must be taken into consideration when performing engineering wind-resistant design and TC disaster mitigation in the coastal areas of China that are subject to the frequent passages of TCs. At present, TC engineering wind fields are usually estimated by simplified parametric models, resulting in large departures from observations. In this study, an engineering wind model based on the Weather Research and Forecasting (WRF) model for TCs (EMTC) is developed for engineering wind-resistant design. Results show that the EMTC model could output fine-scale wind fields, which are similar to the observations. By introducing TC intensity modification and developing the topographical transformation technique in the WRF, the TC could be sculptured to the requested intensity and track according to the needs of engineering wind-resistant design. Verifications using two examples demonstrate that the model could match the target terrain with any TC track and intensity, providing accurate TC wind simulations for wind-resistant designs. Based on model outputs at 1-km horizontal resolution and 10-min intervals, engineering wind parameters such as the wind attack angle, the maximum wind speed, horizontal wind speed shear, temporal variation of wind speed and direction, and storm relative helicity are calculated to qualify the effects of TC-induced strong wind on engineering structures. These wind engineering parameters can efficiently indicate stronger risk regions of a TC, such as the inner core and spiral rain bands, demonstrating that the EMTC is able to simulate the TC structure reasonably well, and provide quantitative references for wind-resistant design.