The Madden‐Julian oscillation (MJO) is a significant contributor to climate variability in the tropics. While many studies have examined the MJO, few have considered its termination. Multiple indices exist to track and forecast the MJO although the influence of each index on MJO decay has not been documented. This study presents an intercomparison of several MJO indices for a 34‐year period to examine the evolution of MJO events and comprises an index‐specific climatology for MJO termination. We present an analysis of common indices including the OLR‐based MJO index (OMI) and filtered OMI (FMO) in addition to the real‐time multivariate MJO (RMM) and velocity potential MJO (VPM) index. Normalized empirical orthogonal function comparisons reveal only minor shifts in longitude and time in the corresponding convection and circulation anomalies between indices. The daily rate‐of‐change (ROC) for each index is derived, and we find that the RMM and VPM indices experience twice as large of daily amplitude changes as the univariate indices. Results from the ROC analysis are implemented in an MJO event identification algorithm to study the sensitivity of MJO termination to changes in the temporary minimum amplitude and threshold used to define events. The corresponding counts of primary, continuing, and circumnavigating events are recorded with primary events being robust to changes in the temporary minimum amplitude. Finally, an MJO climatology is created that presents MJO termination as a function of phase for each index. Physical reasons behind differences in the termination climatology are proposed in addition to applications for future work.

中文翻译：

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MJO事件和终止的索引比较

Madden-Julian振荡（MJO）是热带地区气候变化的重要因素。尽管许多研究已经对MJO进行了研究，但很少有人考虑终止它。尽管没有记录每个指标对MJO衰减的影响，但存在多个指标来跟踪和预测MJO。这项研究提供了34年期间多个MJO指数的比对，以检查MJO事件的演变，并包括MJO终止的特定于指数的气候。除了实时多元MJO（RMM）和速度势MJO（VPM）索引外，我们还对常见索引进行了分析，包括基于OLR的MJO索引（OMI）和已过滤OMI（FMO）。归一化的经验正交函数比较显示，在指数之间相应的对流和环流异常中，经度和时间只有很小的变化。推导出每个指数的每日变化率（ROC），我们发现RMM和VPM指数的每日振幅变化是单变量指数的两倍。ROC分析的结果在MJO事件识别算法中实现，以研究MJO终止对用于定义事件的临时最小幅度和阈值变化的敏感性。记录主事件，连续事件和绕行事件的相应计数，其中主事件对临时最小幅度的变化具有鲁棒性。最后，创建了一个MJO气候，该气候将MJO终止表示为每个索引的相位的函数。