Diversity of Tropical Intraseasonal Oscillation

热带地区的大尺度大气环流在几个月的时间尺度上有强烈的波动。这种热带季节内振荡（ISO）主要由11月至4月的马登-朱利安振荡（MJO）现象和6月至10月的北方夏季季节内振荡（BSISO）现象所主导。MJO通常会激发向东演变的增强降雨（和深云）模式，而BSISO则会产生向东北迁移的强降雨模式。这两种现象对全球天气和气候都有很大影响。最近的观测表明，与MJO/BSISO相关的事件是相当多样化的，在结构，传播，生命周期和全球影响方面存在显着差异。描述和理解ISO的分布及其气候变化对于真实模拟和准确预测全球大气变化是至关重要的。然而，迄今为止，它们在很大程度上是未知的。因此，本研究旨在揭示ISO多样性的独特形式及其对极端天气事件的影响，并了解控制多样性及其年代际变化和未来变化的基本过程。这项研究的结果可以为热带动力学和季风提供新的认识，并改善受ISO影响的10亿多人口地区的天气和气候预报。研究人员计划主办一次国际讲习班，以激发社区对ISO的兴趣。他将指导一名博士后研究科学家和培训一名研究生。具体研究目标是：（a）探测和表征ISO在其启动、传播、结构、放大/衰减和影响方面的全方位多样性，（B）阐明ISO多样性行为产生的机制，（c）揭示ISO年代际变率的全球和区域来源，以及（d）量化ISO多样性对人为强迫的响应。为了解决这些目标，研究人员将采用一种策略相结合的过程和面向动态的诊断，理论分析和建模。这项工作的结果可能会导致一个新的概念框架，了解ISO的复杂性和一个新的途径，以解开ISO的十年变化的根本原因，其未来的changes.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The large-scale atmospheric circulation in the tropical region strongly fluctuates on a timescale of a few months. Such tropical intraseasonal “oscillation” (ISO) is dominated by the Madden-Julian Oscillation (MJO) phenomenon between November-April and the Boreal Summer Intraseasonal Oscillation (BSISO) phenomenon between June-October. The MJO typically elicits patterns of enhanced rainfall (and deep clouds) that evolve eastward while BSISO produces northeastward migrating intense rainfall patterns. Both phenomena greatly impact weather and climate worldwide. Recent observations have revealed that events associated with MJO/BSISO are quite diverse, differing strikingly in structure, propagation, lifecycle, and global impacts. Characterization and understanding of ISO diversities and their climate variations are crucial for realistic modeling and skillful prediction of global atmospheric variations. However, to date, they are largely unknown. Thus, this research aims to reveal the distinctive forms of ISO diversity and its impacts on extreme weather events, and to understand the fundamental processes governing the diversity and its decadal variability and future change. Results from this research can shed new light on tropical dynamics and monsoons as well as improve weather and climate forecasting for regions of over 1 billion people impacted by ISO. The researcher plans to host an international workshop to galvanize community interests in ISO. He will mentor a post-doctoral research scientist and train a graduate student.The specific research objectives are to: (a) detect and characterize a full range of ISO diversity in their initiation, propagation, structure, amplification/decay, and impacts, (b) elucidate the mechanisms responsible for generation of the diversified ISO behavior, (c) reveal global and regional sources of ISO decadal variability, and (d) quantify how the ISO diversity responds to anthropogenic forcing. To address these objectives, the researcher will employ a strategy of combining process- and dynamics-oriented diagnostics, theoretical analyses, and modeling. Results from this work may lead to a new conceptual framework for understanding ISO complexity and a new avenue to unravel root causes of ISO decadal variability and its future change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.