台风条件下南海海域超长重现期波高推算的研究

The Study on the Estimation of Very Long Return-Period Significant Wave Height During Hurricane in the Region of China South Sea

本文利用中国气象局—上海台风研究所(CMA-STI)时间跨度为68a的热带气旋最佳路径数据集,针对在中国南海受台风影响的站点,选择主要的台风特征要素并分别进行拟合,得到各自的概率密度函数,并建立各个台风特征要素的联合概率模型,利用蒙特卡罗模拟结合参数化台风风浪模型推算出台风条件下的超长重现期(超越概率小于等于10-3)波高。将该方法所得的结果与传统方法的计算结果进行比较,结果表明对于较短重现期(超越概率大于等于10-2)波高的推算,联合概率法与传统方法得到的结果较为接近;而对于超长重现期波高的推算,基于联合概率的模拟法不受风浪观测样本数量限制,所得结果有较小的变异系数,证明了该方法在数据集时间跨度较短时,在推算超长重现期波高方面相比于传统计算方法结果更为可靠。在观测数据较为缺乏的南海海域,基于联合概率的模拟法是一种推算重现期波高的有效手段。

This paper provides a joint probability method(JPM)model for calculating hurricane-induced waves with lower annual exceedance probability(usually lower than 10-3)along the China South Sea,using available CMA-STI dataset.The objective of this paper was to develop and apply this probabilistic model for hurricane affecting platform sites in the China South Sea,compare the predictions of this model to traditional approach within relatively higher annual exceedance probability,investigate and calculate the waves for platforms in very long return-period.The storm characteristics(i.e.central pressure deficit,minimum distance,radius of maximum wind speed and forward velocity)are generated by the means of Monte Carlo simulation for use as inputs to numerical winds and waves model.For estimation with relatively higher annual exceedance probability(usually larger than 10-2),the results from JPM are consistent with results via conventional way;for estimation with lower annual exceedance probability,the JPM method is not subjected to the size of observed data,and the lower variable coefficient shows its reasonability and reliability in the estimation of seastates with lower annual exceedance probability without sufficient observed data.