1961-2014年中国沿海极端气温事件变化及区域差异分析

基于1961-2014年156个地面气象站日尺度的气温数据集，利用趋势分析、小波分析、Mann-Kendall检验、累积距平、Pettitt检验、主成分分析等方法分析了中国沿海地区极端气温事件的时空变化特征。结果表明：中国沿海及各子区域极端气温暖指数呈上升趋势，冷指数和气温日较差呈下降趋势，夜指数的年际倾向率明显大于昼指数的年际倾向率；除相对指数、极高值指数和冷（暖）持续日数的多年均值在各子区域之间相差不大以外，霜冻日数、冰冻日数以及气温日较差的多年均值从北至南依次递减，与之相反，夏季日数、热夜日数、极端气温极低值指数以及生长季长度的多年均值则从北至南依次增加。各子区域极端气温指数年际间的主周期介于2-8 a，均无显著的年代际震荡周期；各子区域极端气温指数的突变主要发生在1980s和1990s期间，冷指数和极低值指数的突变时间稍早于暖指数和极高值指数的突变时间，突变后，极端暖事件和气温的极值事件进入多发阶段，极端冷事件进入相对少发的阶段；主成分分析中第一主成分高载荷的极端气温指数对日均气温和日最高（低）气温均有较好的指示性，这类极端指数两两之间的相关性也较强，低载荷的极端气温指数对日均气温和日最高（低）气温的指示性相对较弱，与其他极端气温指数之间的相关性也均较弱。

Analysis of spatiotemporal variations and regional differences in extreme temperature events in the coastal area of China during 1961-2014

Based on the daily temperature dataset of 156 weather station records, a set of statistical methods, including trend analysis, Wavelet analysis, Mann-Kendall test, accumulative anomaly analysis, Pettitt test, and principal component analysis was employed to investigate the spatial and temporal variations of the extreme temperature events from 1961 to 2014 in the coastal area of China. Results of the trend analysis demonstrated an upward trend in warm extremes and a downward trend in cold extremes as well as diurnal temperature range (DTR). The decadal trend rates of the night extremes were obviously higher than those of the day extremes in the coastal area of China. Generally, a decrease was observed in the multi-year averages of the frost days (FD0), ice days (ID0) and diurnal temperature range (DTR), and an increase was observed in the mutil-year averages of the summer days (SU25), tropical nights (TR20), minimum value of daily maximum temperature (TNx), minimum value of daily minimum temperature (TNn) and growing season length (GSL) from north to south. However, a little variation was observed in the multi-year averages of the cool days (TX10p), cool nights (TN10p), warm days (TX90p), warm nights (TN90p), maximum value of daily maximum temperature (TXx), maximum value of daily minimum temperature (TNx), cold spell duration index (CSDI) and warm spell duration index (WSDI) between the sub-regions and the entire coastal area of China. The primary period of extreme temperature indices varied from 2 to 8 years in the sub-regions of the coastal area of China, and no significant decadal period was detected. The mutation time of extreme temperature indices occurred mainly in the 1980s and the 1990s in all sub-regions. Additionally, the cold extremes and minimum values of daily maximum (minimum) temperature mutated earlier than those of the warm extremes and maximum values of daily maximum (minimum) temperature. After mutation, the extreme warm events and extreme value events tended to occur frequently, whereas the occurrence of extreme cold events decreased gradually. The extreme temperature indices holding high load in the first principal component showed strong positive correlations with each other and exhibited high contributions to the daily average and daily maximum (minimum) temperature. On the other hand, the extreme temperature indices holding low load in the first principal component presented weak correlations with other extreme indices and showed low contributions to the daily average and daily maximum (minimum) temperature.