This study shows that the Boreal Summer Intraseasonal Oscillation (BSISO) dominates the Indian summer monsoon low‐precipitation bias in the Met Office Unified model. Analyzing a recent 9‐year period (June, July, August only), it is found that the precipitation bias is dominated by break and break‐to‐active transition BSISO phases, while some of the other phases have no bias at all over a 7‐day forecast. Evidence of a link to upstream effects is found, in that there is a delayed reduction in the moisture flux entering India from the west. It is also shown that an increase in the net flow of moisture out of India to the east is strongly linked to the low‐precipitation bias, and there is some evidence that this is related to a lack of low‐pressure systems over India. Most atmospheric models have substantial rainfall biases over India, and these results may indicate the circulation patterns responsible.

中文翻译：

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统一模型中印度夏季风降水预报的偏差及其与BSISO指数的关系。

这项研究表明，在Met Office Unified模型中，北方夏季季节内振荡（BSISO）主导了印度夏季季风的低降水偏向。分析最近的9年时间段（仅6月，7月，8月），发现降水偏向主要由BSISO阶段和从断裂到主动转变的阶段主导，而其他一些阶段在整个7天预报。发现与上游效应有关的证据是，从西部进入印度的潮气通量有所减少。研究还表明，从印度向外流向东部的水分净流量增加与低降水偏倚密切相关，并且有证据表明，这与印度缺乏低压系统有关。大多数大气模式在印度各地都有很大的降雨偏差，