浅谈极端气温事件研究中阈值确定方法
Discussion on Threshold Determination in Defining Extreme Temperature Indices
中文摘要：
比较了极端气温事件研究中，绝对阈值和相对阈值指数的适用范围。归纳总结了近年来国内外在陆地极端气温事件研究中，相对阈值百分位选取、修订以及资料和计算方法的异同，评价了不同计算方法的优缺点和适用范围，讨论了参考期选取的影响。综合已有研究结论发现，采用不同的相对阈值计算方法检测出的极端气温事件长期趋势以及变异性特征差异极小。为了增强极端气温事件趋势变化分析的统计意义，以及对不同研究和不同区域分析结果进行比较，在资料选择和处理、阈值计算方法、气候基准期的确定等方面还需要进一步完善和规范。
中文关键词：
极端气温事件，绝对阈值，相对阈值，计算方法，气候参考期
KeyWords：
extreme temperature events, fixed threshold, percentile threshold, methods of calculation, climate baseline period
Abstract：
In this paper, the application scope of fixed threshold and percentile threshold index is compared during extreme temperature events. Also, the determination of percentile thresholds for defining extreme temperature indices in studies of longterm change of extreme temperature events is briefly summarized, and the differences of data and calculation methods used in different studies are compared. The effect of reference-period selection on percentile threshold values and the results of analyses are discussed. It is clear from the overview that both advantages and disadvantages exist for different methods of percentile threshold determination. It is found that the long-term trends of extreme temperature events detected are almost the same when different methods of calculation are used. In order to enhance the significance of the statistical analysis of extreme events, trends and to compare the analyses among different studies and different regions, however, it is necessary to further improve the methods of data selection, data processing, threshold calculation methods and the usage of climate baseline period. It is advisable to consistently use the uniform methods for determining percentile thresholds.