Abstract The precipitation of the entire Indian sub-continent is primarily driven by the monsoon wind system, which throws a tough challenge to model changes due to its natural variabilities. Additionally, the unique geographical location and diverse climatic condition of the Indian state of West Bengal (WB) accelerates this challenge even more. Such a situation can be more complicated if the assumption of randomness in the Mann-Kendall (MK) test is not taken care of. The present study inspects the dynamics of precipitation using the original MK test along with its three modified versions in WB. The modified versions are considered to incorporate all the significant autocorrelation coefficient (ACC) along with the short and long term persistence (STP and LTP) in the time series. Results showed that the presence of significant ACC was more common than the LTP behavior. The STP approach produced similar results to the original MK test, while the LTP approach reduced the number of significant trends. When the series was free from the scaling effect, consideration of all significant ACC gave better result in comparison to the STP approach. The annual precipitation is decreasing in large areas of WB, while the coastal areas are receiving increasing trends, which can intricate the estuarine and coastal processes. The Sub-Himalayan region and the western parts of WB are experiencing significant falling trend in monsoon season. Such a decreasing trend can enhance drought vulnerabilities, especially in the western parts of WB. However, the other three seasons (pre-monsoon, post-monsoon, and winter) witness the maximum number of non-significant trends.

中文翻译：

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印度西孟加拉邦长期降水变化分析：一种检测受自相关影响的单调趋势的方法

摘要 整个印度次大陆的降水主要受季风系统驱动，其自然变异性对模式变化提出了严峻挑战。此外，印度西孟加拉邦 (WB) 独特的地理位置和多样化的气候条件进一步加速了这一挑战。如果不考虑 Mann-Kendall (MK) 检验中的随机性假设，这种情况可能会更加复杂。本研究使用原始 MK 测试及其在 WB 中的三个修改版本来检查降水动态。修改后的版本被认为包含所有显着的自相关系数 (ACC) 以及时间序列中的短期和长期持久性（STP 和 LTP）。结果表明，明显 ACC 的存在比 LTP 行为更常见。STP 方法产生与原始 MK 测试相似的结果，而 LTP 方法减少了显着趋势的数量。当序列没有缩放效应时，与 STP 方法相比，考虑所有重要的 ACC 给出了更好的结果。WB 大片地区的年降水量正在减少，而沿海地区则有增加的趋势，这可能会导致河口和沿海过程错综复杂。亚喜马拉雅地区和西伯利亚西部地区在季风季节呈明显下降趋势。这种下降趋势会增加干旱的脆弱性，特别是在 WB 西部地区。然而，其他三个季节（季风前、季风后、