基于站点实测风速的中国台风大风重现期估计

Estimation on the Frequency of Typhoon Wind Speed over China Based on Historical Wind Observations from Weather Stations

首先基于1951-2014年中国地面气象站点历史风速观测数据和CMA-STI热带气旋最佳路径数据集,提取了站点历史台风过程影响风速;其次,利用极大似然法估计Gumbel分布、Frechet分布以及Weibull 3种分布模型参数,优选出最适模型进行站点极值风速年最大值风速拟合,计算不同重现期风速值并利用bootstrap方法对各重现期计算结果的不确定性进行量化,得到典型重现期下中国台风大风风速的90%置信区间;最后,根据包括克里金法、反距离权重法、自然邻域法、最近邻法在内的4种空间插值方法对于台风大风的插值效果得到中国东部沿海1km网格不同重现期台风风速分布及其90%置信区间。结果表明:东南沿海地区是台风极值大风影响最严重的区域,典型重现期台风风速估计的不确定性较大,不确定性的高值区域也主要分布在东南沿海地区。

China has been suffering great loss from typhoon wind damage over the past few decades, and typhoon wind hazard assessment plays an essential role in typhoon risk management. Based on historical ground wind observation data and the CMA-STI best track dataset, historical wind speeds induced by typhoon at each weather station of China are obtained. Kriging, Inverse Distance Weighted, Natural Neighbor and Nearest Neighbor methods were compared according to cross validation results of typhoon wind interpolation. By using maximum likelihood method, the optimal distribution model was selected from Gumbel distribution, Frechet distribution and Weibull distribution for each station, whose annual maximum historical typhoon wind speed was extracted, then the spatial distribution of maximum typhoon wind speeds of expected value and 90% confidence intervals at typical return periods were derived with the application of the optimal spatial interpolation method. The findings indicate that: the maximum typhoon wind speed and corresponding uncertainty decreases from the southeast to the northwest gradually at a certain return period, the southeast coastal region seems to be the most affected area.