The Lancang‐Mekong River Basin (LMRB) in Mainland Southeast Asia is home to ~70 million people, mostly living in poverty and typically working in primary freshwater‐related sectors, particularly agriculture and fishery. Understanding the mechanisms of the historical variability in precipitation (as the crucial water source) plays a key role in regional sustainable development throughout the LMRB. Herein, the spatiotemporal variability in interannual and intra‐annual precipitation over the LMRB was analyzed using the Global Precipitation Climatology Centre (GPCC) data for the period 1952–2015. The empirical orthogonal function (EOF) and wavelet transform coherence methods were utilized to investigate the relationships of such historical variations in annual (water year: November–October), dry season (November–May), and wet season (June–October) precipitation with 13 different climate teleconnections (eight large‐scale oceanic‐atmospheric circulation patterns and five summer monsoons). On the basin scale, only a significant (p < 0.05) wetting trend in the dry season precipitation (DSP) was uncovered. Spatially, significant wetting (drying) trends in annual precipitation detected over the northeastern (most western) parts of the Mekong River Basin during the water years 1952–2015, largely contributed by the substantial increases (decreases) in historical wet season precipitation. The most important precipitation pattern (EOF1) was identified as a strong (relatively weak) positive center in the eastern (southwestern) Mekong River Basin accompanying by a significantly high (relatively low) positive value for the first EOF mode of the dry season precipitation (wet season precipitation). Precipitation variability in the LMRB was significantly associated with the South Asian Summer Monsoon Index, Southern Oscillation Index, and Indian Summer Monsoon Index.

中文翻译：

---

1952年至2015年影响澜沧江-湄公河流域的气候遥相关对时空变化的影响

东南亚大陆的澜沧江-湄公河流域（LMRB）约有7000万人，其中大部分生活在贫困中，通常在与淡水有关的主要部门工作，尤其是农业和渔业。理解降水历史变化的机制（作为关键的水源）在整个LMRB地区的区域可持续发展中发挥着关键作用。在此，利用1952-2015年全球降水气候中心（GPCC）的数据分析了LMRB的年际和年内降水的时空变化。经验正交函数（EOF）和小波变换相干方法用于研究年度（水年：11月至10月），旱季（11月至5月），13个不同的气候遥相关点（8个大型海洋-大气环流模式和5个夏季风）形成的湿季（6-10月）降水。在流域范围内，只有p <0.05）在干季降水（DSP）中发现了润湿趋势。在空间上，1952年至2015年水域期间，在湄公河流域东北部（最西部）检测到的年降水量有明显的湿润（干燥）趋势，这在很大程度上归因于历史湿季降水的大幅增加（减少）。在湄公河流域东部（西南）流域，最重要的降水模式（EOF1）被确定为强（相对弱）正中心，而旱季降水的第一个EOF模式伴随着明显较高（相对较低）的正值（雨季降水）。LMRB的降水变化与南亚夏季风指数，南部涛动指数和印度夏季风指数显着相关。