基于随机事件集的风暴潮重现期计算的合理性研究

为了研究随机事件集实际应用于计算南通如东岸段风暴增水的合理性问题,基于ADCIRC模型模拟影响南通如东岸段基于随机事件集的风暴增水,然后利用P-Ⅲ型曲线对年增水极值进行拟合,得到各典型重现期下的增水值,并与由28年历史资料拟合得到的各重现期下增水值进行对比。结果表明,在历史资料长度所及的28年以及以下重现期,基于随机事件集模拟得到的重现期增水值与基于历史实测资料的比较符合,说明随机事件集的结果在低重现期情况下结果良好。对于高重现期增水值,基于随机事件集的拟合结果显著大于基于历史资料的拟合结果。由于历史资料时间太短,不足以发生非常极端的风暴潮事件,故对高重现期的拟合结果难以保证可信度,所以不能排除随机事件集拟合结果的合理性。随机事件集在南通如东岸段对低重现期增水估计准确,同时也能较充分地估计高重现期增水,在目前缺乏百年千年时间尺度的实测资料的情况下,不失为一种良好的风暴增水重现期计算工具。在全球变暖情况下,超强台风出现几率大大增加,典型重现期增水值也会相应提高,为了预防风暴灾害的侵袭,需要加深加固海堤、江堤等海岸工程。

Study on the reasonability of computing the return period of storm surge based on random event sets

In order to study whether the random event set can be used in the Rudong bank of Nantong or not, ADCIRC model is used to stimulate the storm surge affecting the Rudong bank based on random event set. Then p-III curve is used to fit peak-value of surges of all the years to get the surge of typical return periods. The result shows that the results of fitting by ADCIRC and by historical data coincide well in lower return periods, but for higher return periods, the results of fitting by ADCIRC are significantly higher than that of fitting by historical data. Due to the short time, it''s not enough for the extreme storm surge events to occur, and the results of higher return periods are not reliable, so we can''t rule out the reasonability of results based on random event set. The results of fitting based on random event set are accurate in lower return periods and we can also fully estimate the surge of higher return periods based on random event set. In the situation of lacking historical data of hundreds of year,random event set can be accepted as a tool to compute the return period of storm surge. Considering the global warming, the possibility of super typhoons'' appearance rises, which will result in higher surge of return periods. In order to prevent the disaster of storm surge, the government needs to deepen and reinforce the coastal engineering like seawalls and embankments.