Summer precipitation in Thailand is a major resource for water and agriculture. Understanding the decadal variations of summer precipitation is useful for water resource management planning for long-term periods. This study investigates decadal changes in summer precipitation in Thailand. An evident increase in summer precipitation was found after the mid-1990s, and the possible causes have been discussed. An analysis of precipitation from observational stations revealed a significant shift in 1994; an increase in summer precipitation can be observed over most of Thailand after 1994. Inspections of the atmospheric circulation revealed cyclonic anomalies over the Indochina Peninsula in the lower troposphere, facilitating enhanced moisture transport towards Thailand. Meanwhile, the anomalous local Hadley circulation over eastern Thailand demonstrated stronger ascending motion after 1994, facilitating enhanced precipitation. The abovementioned changes in the atmospheric circulation and summer precipitation are closely related to the decadal changes in the sea surface temperature over the Atlantic Multidecadal Oscillation.

泰国的夏季降水是水和农业的主要资源。了解夏季降水的年代际变化对于长期的水资源管理计划很有用。这项研究调查了泰国夏季降水的年代际变化。在1990年代中期之后，发现夏季降水明显增加，并且已经讨论了可能的原因。对观测站降水的分析表明，1994年发生了重大变化。1994年之后，泰国大部分地区的夏季降水有所增加。对大气环流的检查表明，对流层下部印度支那半岛上空的气旋异常，促进了向泰国的水汽输送。与此同时，1994年以后，泰国东部地区哈德利环流的异常表现出较强的上升运动，促进了降水的增加。上述大气环流和夏季降水的变化与大西洋多年代际涛动的海面温度的年代际变化密切相关。