基于低频特征信号的高温热浪特征分析
High-Temperature Heat Wave Characteristic Analysis Based on Low-Frequency Characteristic Signal

为了进一步研究低频信号对西南地区高温天气过程的影响，基于国家气象信息中心提供的1979年~2015年间我国地面站点逐日最高气温数据，通过天气学诊断分析方法以及谱分析法，对西南区域发生的高温天气过程与低频信号的联系进行研究分析。结果表明：1) 西南地区6~8月逐日最高气温具有显著的周期为10~30 d、30~80 d的低频振荡特征。提取10~30 d、30~80 d的低频分量，可以看出最高气温10~30 d以及30~80 d的低频振荡，尤其是峰谷值相位的变化与实际气温的变化有很高的相似度，能够很好地反映持续性强、弱气温变化的交替演变过程。2) 西南地区高温热浪过程与10~30 d、30~80 d的低频信号有关，且10~30天的信号贡献最为显著。3) 观察发生高温热浪时，低频环流场的形势，可以发现，10~30 d与30~80 d的环流皆有贡献，10~30 d与30~80 d两种环流的低频信号跟中高纬以及低纬的振荡信号有关，对于预报西南地区的高温过程具有重要作用。
In order to further study the impact of low-frequency signals on the high-temperature weather process in the southwest region, based on the daily maximum temperature data of China’s ground stations from 1979 to 2015 provided by the National Meteorological Information Center, through weather diagnostic analysis methods and spectral analysis methods, research and analysis of the relationship between high temperature weather process and low frequency signal. The results show that: 1) The daily maximum temperature from June to August in the southwest region has significant low-frequency oscillation characteristics with periods of 10 - 30 d and 30 - 80 d. Extracting the low frequency components of 10-30d and 30 - 80 d, it can be seen that the low temperature oscillations of the maximum temperature of 10 - 30 d and 30 - 80 d, especially the change of the peak-valley phase and the actual temperature change have a high degree of similarity, it can well reflect the alternating evolution of the continuous strong and weak temperature changes. 2) The high-temperature heat wave process in the southwest is related to the low-frequency signals of 10 - 30 d and 30 - 80 d, and the signal contribution of 10 - 30 days is the most significant. 3) Observing the situation of the low-frequency circulation field when high-temp- erature heat waves occur, it can be found that the circulations of 10 - 30 d and 30 - 80 d both contribute, and the low-frequency signals of the two circulations of 10 - 30 d and 30 - 80 d are related to the mid-high latitude and low latitude oscillation signals. The latitude oscillation signal is related to the prediction of high temperature processes in the southwest region.