地形起伏变化下的边界层参数化台风风场模型

对于登陆台风来说,采用平坦下垫面和单一的地表粗糙长度假设并不能与实际情况相吻合.为了更准确地模拟台风近地面风场,基于现有参数化台风风场模型,采用随地形变化的坐标系建模方法和高精度地形与土地覆盖资料,考虑了台风登陆过程中地形起伏和土地覆盖变化的影响.针对历史上影响广东省的3个台风案例,利用大量观测数据对比和验证了改进后的台风风场模型.对比结果表明:改进后的参数化台风风场模型对风速的模拟并没有表现出明显的系统偏差,并且能较好地模拟出台风登陆过程中风速风向的时程变化.

Parametric boundary typhoon wind field model under terrain undulation

The traditional parametrical typhoon wind filed models are based on assumption of flat underlying surface and uniform surface roughness length, which cannot characterize the actual continent. To simulate the near-surface wind field accurately, actual terrain fluctuation and land surface vegetation cover were modeled by terrain-changing coordinate system modeling method and high-precision geographic data based on the existing models. Observation data of three typhoons landing in Guangdong were used to verify the improved parametrical typhoon wind field model. Results of the improved model did not show systematic deviations in the simulation of wind field. Moreover, it can better simulate the time history of wind speed and direction during the landfall of typhoon than the traditional models.