平均时距对良态风气候地区极值风速的影响研究

STUDY ON THE EFFECT OF AVERAGE TIME INTERVALS ON EXTREME WIND SPEED IN NORMAL WIND CLIMATE AREAS

在风气候分析中,风速观测历史数据一般来源于各气象站的归档测量,但不同气象站采用的平均时距并不统一,这导致基于风速观测历史数据的极值风速预测过程存在平均时距的转换问题。该文对美国11座处于良态风气候地区城市气象站记录的风速连续观测数据,进行处理得到不同时距下平均风速序列,并将改进独立风暴法与极值I型分布模型相结合分析得到各重现期的风速极值,分析了平均时距对极值风速预测结果的影响。研究结果表明:在良态风气候地区,一定重现期的极值风速随平均时距的增大而减小,近似呈指数律衰减;平均时距对极值风速的影响规律基本不受极值风速重现期的影响;1 min平均时距下的极值风速比10 min平均时距极值风速大19%左右。基于这些结果,拟合给出了良态风气候地区不同平均时距极值风速的转换关系式。

In wind climate analysis,historical wind speed data generally comes from archived measurements of meteorological stations.The average time intervals adopted by different meteorological stations are not consistent.The difference in the average time intervals leads to a conversion problem of the average time intervals in the extreme wind speed prediction process when the samples are based on the historical data of wind speed.Continuous observation of wind speed recorded by 11 meteorological stations in normal wind climate areas in the United States was processed to obtain the wind speed sequences at different average time intervals.The extreme wind speeds of return periods were obtained by using the improved independent storm method and the extreme I distribution model.Subsequently,the influence of average time intervals on the prediction results of extreme wind speed was analyzed.The result shows that in normal wind climate areas,the extreme wind speed decreases with the increase in the average time interval,and it approximates an exponential attenuation;the influence of the average time intervals on the extreme wind speed is basically not affected by the return periods;and the extreme wind speed with a sampling average time interval of one minute is about 19%higher than that with a sampling average time interval of ten minutes.Based on these results,the conversion formula of extreme wind speed with different average time intervals in normal wind climate areas was proposed.