时间接缝评分：用于评估时间序列已知转换处连续性的方法
Temporal Seam Score for Assessing Continuity at Known Transitions in Time Series
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- Lund University（隆德大学）
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中文总结 AI 辅助
本文提出时间接缝评分（S-score），一种有符号稳健度量，用于评估时间序列已知转换处的连续性，无需时间重叠，支持传感器换代时的协调质量保证。
中文摘要 AI 辅助
长期环境记录日益增多地结合了来自相继观测或处理系统的观测数据。这些系统之间的转换会产生时间接缝，这些接缝可能反映不完善的协调或观测过程的变化。我们引入了时间接缝评分（S-score，或S），这是一种有符号的、稳健的度量，用于评估已知转换时间点的连续性。完整的时间序列使用一个不考虑接缝的模型进行拟合，该模型考虑了趋势、季节性和可选的协变量。转换周围对称窗口内的残差对比与在构成片段内计算的匹配参考对比进行比较。S-score是接缝对比相对于该参考的标准差偏离。接近零的S-score表明接缝与普通的时间变异性一致。其符号表示不连续性的方向，而其幅度（|S|）表示该不连续性的异常程度。模拟表明，|S|反映了相对于残差变异性的施加不连续性：在残差变异系数为0.10时，20%的位移产生的|S|中位数为2.58，而在0.50时为0.84。在MODIS到Sentinel-3的植被记录中，500个站点中有121个产生了有限的S-score，其中90个满足所有可靠性标准。在这些可靠站点中，S的中位数为+0.217，|S|的中位数为0.627，表明几乎没有系统性方向位移，中位接缝偏离低于一个参考扩散。S-score提供了一种通用且可审计的诊断方法，用于评估跨代传感器、算法和观测系统的时间连续性，而无需时间重叠，从而支持协调质量保证和基于长期环境记录的更可靠的归因分析。
英文摘要
Long environmental records increasingly combine observations from successive observing or processing systems. Transitions between these systems create temporal seams that may reflect imperfect harmonization or changes in the observed process. We introduce the Temporal Seam Score (S-score, or S), a signed, robust measure for assessing continuity at a known transition time. The complete time series is fitted with a seam-blind model accounting for trend, seasonality, and optional covariates. The residual contrast between symmetric windows around the transition is compared with matched reference contrasts calculated within the contributing segments. The S-score is the standardized departure of the seam contrast from this reference. An S-score near zero indicates that the seam is consistent with ordinary temporal variability. Its sign indicates the direction of the discontinuity, while its magnitude (|S|) indicates how exceptional the discontinuity is. Simulation showed that |S| reflects the imposed discontinuity relative to residual variability: a 20% shift produced a median |S| of 2.58 at a residual coefficient of variation of 0.10, compared with 0.84 at 0.50. In a MODIS-to-Sentinel-3 vegetation record, 121 of 500 sites yielded finite S-scores, of which 90 met all reliability criteria. Among these reliable sites, median S was +0.217 and median |S| was 0.627, indicating little systematic directional displacement and a median seam departure below one reference spread. The S-score provides a general and auditable diagnostic for evaluating temporal continuity across generations of sensors, algorithms, and observing systems without requiring temporal overlap, thereby supporting harmonization quality assurance and more reliable attribution analyses based on long-term environmental records.
