淮河流域高温热浪时空演变规律及成因分析

基于淮河流域1960—2014年39个气象站点数据、太平洋气候因子和NECP/NCAR再分析数据基础，利用空间Ward-like层次聚类分析划分4个子区域，通过体感温度的高温热浪指数分析淮河流域不同分区的夏季高温热浪时空演变特征，并通过EOF分析、相关性分析和大气环流遥相关等进一步揭示淮河流域高温热浪演变机理。研究表明：① 1960—2014年淮河流域夏季高温、高温热浪开始时间和持续时间均呈先增后减的趋势，20世纪80年代由暖相位进入冷相位，2010年后由冷相位进入暖相位；② 淮河流域各分区高温热浪开始时间呈现区域差异，分区1的高温热浪事件开始时间最早（平均为5月28日），分区3次之（平均为6月1日），分区2和分区4高温热浪开始时间最晚；③ 淮河流域轻度热浪发生频次最多平均为1.24次/a，中度热浪发生频次次之，平均为0.37次/a，重度热浪发生频次最少，平均为0.04次/a；淮河流域高温热浪事件与太平洋东部变暖（厄尔尼诺）或变冷（拉尼娜）变化相同。④ 青藏高原和内蒙古低压减弱导致了热浪高温事件的增加。分区4和分区1发生热浪的时间主要发生6、9月，分区2和分区3热浪发生时间集中在7、8月。分区1（西部）和分区4（东部）与Niño3、Niño1+2、MEI和PDO的相关性较高，分区2和分区3与Niño3.4、PNA相关性较高。

High Temperature Heat Waves in the Huaihe River Basin and Relation to the Madden-Julian Oscillation:Spatio-temporal Properties and Causes

To evaluate the spatial change of high temperature heat wave events in the Huaihe River Basin (HRB) and its mechanism, characteristics of high temperature heat waves in the summer were analyzed based on pacific climate factors and NECP/NCAR reanalysis data in the 39 meteorological stations. Four sub-regions were divides via Ward-like hierarchical clustering analysis. Meanwhile, correlation between high temperature heat wave events and atmospheric circulation in the HRB was investigated and the evolution mechanism of high temperature heat wave events explained via EOF analysis and atmospheric circulation teleconnection in the HRB. The study shows that: 1) There are obvious interannual changes in summer temperature that the warm phase changed to the cold phase in the 1980s and the cold phase changed to the warm phase after 2010. The trend of the high temperature heat wave event start time and duration is consistent with that of the summer high temperature time. 2) There are obvious differences in the onset time of high temperature heat wave events in four regions. The onset time of the high temperature heat wave events in subregion 1 is the earliest (May 28), followed by subregion 3 (June 1), and subregion 2 (June 5) and subregion 4 (June 10) the hottest heat wave started at the latest; 3) The frequency of mild high temperature heat waves in the HRB is 1.24, and the frequency of moderate heat waves was the second with an average of 0.37. Severe heat waves have the lowest frequency with an average of 0.04. Moreover, the high temperature heat wave events in the HRB are coincided with the change of warming (El Niño) or cooling (La Niña) in the eastern Pacific Ocean. 4) The weakening of the Qinghai-Tibet Plateau and Inner Mongolia led to heat wave high temperature events increase in the HRB. The heat waves mainly occurred in June and September in subregion 4 and subregion 1, and that in subregion 2 and subregion 3 occurred mainly in July and August. There is significantly correlation between subregion 1, subregion 4 with Pacific North American Index, PDO (North Pacific Ocean Temperature Anomaly), and MEI (Multivariable ENSO Index). However, subregion 2 and subregion 4 have significant correlation with Niño3.4 and Pacific North American Index.