1961~2020年青岛极端高温事件的特征分析

Characteristics of Extremely High Air Temperature Events in Qingdao during 1961~2020

基于1961~2020年青岛气象台日平均气温、日最高气温和日最低气温的观测资料,本文采用气温的概率谱密度95%的阈值百分位法定义极端高温事件,系统地分析了青岛极端高温事件发生的气候特征。结果表明:青岛日平均气温和日最高气温的极端高温阈值分别为26℃和29.5℃,各月极端高温阈值和极端高温事件的日平均气温、日最高气温、日最低气温均表现出一致的单峰型分布特征,1月气温最低,8月最高。但相对于气候平均态的季节变化,青岛极端高温事件日平均气温的季节变化,在春季3~5月主要受日最高气温的异常升温影响,而在冬季的11~1月则与日最高气温和日最低气温共同升温的影响有关。青岛极端高温事件日较差的季节变化呈现出单峰型的季节变化,春季日较差增大,而秋冬季日较差减小。不同季节青岛极端高温事件的发生频率在1961~2020年这60年里年际变化较大,各月累积极端高温频率呈现出在1994年之后显著增加的年代际变化特征。全球变暖的线性趋势在春季对青岛极端高温频发的贡献最大,夏(冬)季青岛极端高温事件的频发主要与日最高(低)气温的年际变化有关;秋季青岛极端高温事件的频发主要与9月较强的升温趋势和日最高气温和日最低气温年际振荡的共同作用有关。

Based on the observed data of daily averaged air temperature (DAAT), daily maximum air temperature (DMaAT) and daily minimum air temperature (DMiAT) of Qingdao Meteorological Observatory from 1961 to 2020, we define extremely high temperature events (EHTE) by threshold percentile method of 95% probability spectral density of air temperature. The climatic characteristics of EHTE in Qingdao are systematically analyzed. Results show that the thresholds of Qingdao DAAT and DMaAT are 26˚C and 29.5˚C, respectively. Seasonal cycles of the threshold, DAAT, DMaAT, DMiAT for EHTE are shown consistent single peak cosinelike distribution, with the lowest temperature in January, and the highest in August. However, compared with the seasonal variation of climatological mean state, the seasonal cycle of DAAT for EHTE in Qingdao is mainly affected by the abnormal warming of DMaAT from March to May in spring, while it is related to the joint warming of DMaAT and DMiAT from November to January in winter. The seasonal cycle of the diurnal range of EHTE in Qingdao showed a single peak curve, with the diurnal range increasing in spring and decreasing in autumn and winter. The frequency of EHTE in Qingdao in different seasons has a great inter-annual variability in the 60 years from 1961 to 2020, and the monthly cumulative frequency of EHTE shows a significant inter-decadal increasing after 1994. The linear trend of global warming contributed the most to the frequency of EHTE in Qingdao in spring, and the frequency of EHTE in summer (winter) season was mainly related to the inter-annual variation of DMaAT (DMiAT). The frequency of EHTE in autumn is mainly related to the strong warming trend in September and the interannual oscillation of DMaAT and DMiAT.