Mid-Latitude Controls on Monsoon Onset and Progression (MiLCMOP)

中纬度地区季风爆发和进展控制 (MiLCMOP)

• 批准号: NE/X000176/1
• 负责人: Andrew Turner
• 金额: $ 61.96万
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX000176%2F1
• 关键词: Mid; Latitude; Controls; Monsoon; Onset

The Indian summer monsoon is critical to the well-being of a billion people since it supplies most of the water for drinking, sanitation, industry and agriculture. Society is so finely tuned to the rains that any variation in their timing, intensity and duration has profound impacts. The onset of monsoon rains typically starts in southern India by 1 June, taking up to 6 weeks to cover the country. Meanwhile, during the monsoon, variations on time scales of a week or more give rise to periods of excess and reduced rainfall, known as active and break events. Being able to better predict the onset of the rains, their progression, and of active and break events in the monsoon would be of great benefit particularly in agriculture, for improved decision-making for planting and use of irrigation and fertilizer. Such advances need improved understanding of how the monsoon progresses across the country and of its behaviour in the computer models used for forecasting and climate prediction. The timing of the monsoon onset is already known to be influenced by variability in the tropics known as the Madden-Julian Oscillation. New research has shown that the mid-latitudes also exert a powerful control. But compared to tropical drivers, the full extent of the extratropical role in monsoon onset progression and in the timing of active and break periods is poorly quantified and understood. The MiLCMOP team earlier led the INCOMPASS field campaign to India, taking new measurements and putting forward new ideas on how the monsoon is controlled, including the concept that monsoon progression can be described as a "tug-of-war" between tropical and extratropical airmasses. This "tug-of-war" is an unsteady process, with a back and forth of the two airmasses before the moist tropical flow takes over for the rest of the season. The MiLCMOP team brings together expertise in monsoon systems and extratropical processes, state-of-the-art modelling at global and convective scales, and in the latest machine learning and causal inference techniques. The time is ripe for MiLCMOP to establish the role of extratropical dynamics on Indian monsoon onset and progression through a detailed investigation of the mid-latitude processes at play. MiLCMOP will use established techniques and develop new metrics to quantify the interactions between monsoon progression and extratropical forcing. These methods will include use of vorticity budgets (examining the sources of changes in circulation) and Lagrangian feature tracking (determining the origin and properties of the different airmasses involved). The vorticity budget and Lagrangian feature tracking tools will be applied to observation-based "reanalysis" and model data in case study years of fast and slow onset behaviour, to determine the dominant mechanisms controlling monsoon progression. The latest global climate models contributing to the IPCC 6th Assessment Report will be tested to see if observed onset processes are represented, while initialised subseasonal and seasonal forecasts (including from project partners at the UK Met Office and India's NCMRWF) will be interrogated to test whether skilful forecasts can be made. New model experiments will be designed and performed to isolate the mechanisms by which extratropical drivers affect monsoon onset and its progression. Finally, novel causal inference techniques will be used to disentangle the effects of extratropical drivers from those in the tropics. MiLCMOP will answer the following key questions: (1) How are the pace and steadiness of Indian monsoon progression affected by interactions with the extratropics in observations and models? (2) What are the mechanisms of extratropical control on ISM progression and variability? (3) In what way do the causal extratropical and tropical drivers of ISM progression offset or reinforce each other and can the competing roles of tropical and extratropical processes be generalised to other monsoons?

印度夏季季风对十亿人民的福祉至关重要，因为它为饮酒，卫生，工业和农业提供了大部分水。社会非常适合下雨，以至于其时间，强度和持续时间的任何变化都会产生深远的影响。季风降雨通常在6月1日开始在印度南部开始，最多需要6周才能覆盖该国。同时，在季风期间，一周或更长时间的时间尺度的变化会导致过度和减少降雨的时期，称为活动和中断事件。能够更好地预测雨水的开始，季风中的积极和中断事件，特别是在农业中有很大的好处，以改善灌溉和灌溉和肥料的决策。这种进步需要提高人们对季风在全国各地如何发展及其在用于预测和气候预测的计算机模型中的行为。季风发作的时机已经被称为Madden-Julian振荡的热带地区的变异性影响。新的研究表明，中段也具有强大的控制。但是，与热带驱动因素相比，季风开始进展以及在活动和休息期的时间安排中的全部范围是量化和理解的。 Milcmop小组早些时候领导了印度的Incompass Field活动，采取了新的测量结果，并提出了有关如何控制季风的新想法，包括季风进步可以描述为热带气体和热带气体之间的“拔河战”。这种“拔河”是一个不稳定的过程，在整个赛季剩余的时间里，在潮湿的热带流动接管之前，这两个空气群的来回来回。 MILCMOP团队汇集了季风系统和诱发过程，全球和对流量表的最新建模以及最新的机器学习和因果推理技术的专业知识。 Milcmop通过详细研究中纬度过程的详细研究来确定印度季风发作和进展的莫尔克莫普的作用已经成熟。 MILCMOP将使用已建立的技术并开发新的指标来量化季风进展和激进强迫之间的相互作用。这些方法将包括使用涡度预算（检查循环变化的来源）和拉格朗日特征跟踪（确定所涉及的不同气压的起源和特性）。涡度预算和拉格朗日特征跟踪工具将应用于基于观察的“重新分析”，并在案例研究的快速和缓慢发作行为的情况下模型数据，以确定控制季风发展的主要机制。将测试有助于IPCC第六次评估报告的最新全球气候模型，以查看是否代表了观察到的发作过程，而初始化的亚季节和季节性预测（包括来自英国会议办公室和印度NCMRWF的项目合作伙伴），以测试是否可以测试是否可以测试非常舒适的预测。将设计和执行新的模型实验，以隔离诱因及其进展的机制。最后，新颖的因果推理技术将被用来解散热带驱动因子的影响。 MILCMOP将回答以下关键问题：（1）印度季风进展的速度和稳定性如何受到观察和模型中与触觉互动的相互作用的影响？ （2）在ISM进展和可变性上，辛地酸内控制的机制是什么？ （3）ISM进展的因果周外和热带驱动因素以何种方式抵消或相互加强，热带和热带过程的竞争作用是否可以推广到其他季风？