Collaborative Research: Dynamics and Predictability of Tropical Weather and Climate through Cloud-resolving Ensemble Assimilation of Sounding and Radar Observations from DYNAMO

马登-朱利安涛动(MJO)是热带大气在季节内时间尺度上的主要模式，对全球天气和气候的许多方面都有重要影响。虽然多年来的观测已经揭示了MJO的基本特征，但其潜在的动力学仍然知之甚少，而且当代的数值天气和气候模式在模拟和预测MJO事件方面的技能较低。最近完成的由美国国家科学基金会赞助的马登-朱利安涛动动力学(DINDO)现场活动针对与印度洋MJO启动关键相关的过程。这项赠款寻求使用基于天气研究和预报(WRF)模式的基于集合的数据同化(ENDA)，通过同化在DINDO期间收集的雷达、探测和卫星观测来探索从对流到季节内尺度的热带天气和气候的动力学和可预报性。对这项研究特别感兴趣的迪纳摩观测是来自三个多普勒雷达的观测，以及来自增强的中尺度探测网络的观测。研究的主要目标包括：(1)通过比较不同的变分、集合和混合资料同化方法，探索最可靠和有效的ENDA方法，用于从对流到区域尺度的热带天气分析和预报；(2)在整个迪纳摩期间，使用最准确和负担得起的ENDA方法进行对流和区域尺度的再分析，并用常规和现场观测以及现有的全球分析或再分析进行验证；以及(3)使用允许对流的(即非常高的时间和空间分辨率)集合分析和预报来检验从对流到季节内尺度的热带天气和气候(包括MJO)的动力学和可预报性。分析和预报还提供了一条有效的途径，从对流到季节内尺度来理解热带天气和气候。广泛的影响：通过博士后研究生和博士后科学家的广泛参与，研究工作将提供教育益处。研究成果也将直接用于课堂教学和指导本科生的研究项目。有关MJO事件的初始化、预报和可预报性的研究结果将改进对热带天气和气候的业务预报，为广大公众提供直接利益，无论他们生活在热带地区还是在世界各地受MJO事件影响的地区。在这种支持下开发的ENDA系统，以及WRF模拟对发电机观测的重新分析，将免费提供在线，并提供大量文件，以造福于更大的学术界。

The Madden-Julian Oscillation (MJO), which is the dominant mode of the tropical atmosphere at intraseasonal time scales, has significant impacts on many aspects of weather and climate across the globe. While the basic features of the MJO have been revealed by observations for many years, its underlying dynamics remain poorly understood and current generation numerical weather and climate models have low skills in simulating and predicting MJO events. The recently completed NSF-sponsored Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign targeted processes critically related to MJO initiation in the Indian Ocean.This grant seeks to use ensemble-based data assimilation (EnDA) based on the Weather Research and Forecasting (WRF) model to explore the dynamics and predictability of tropical weather and climate from convective to intraseasonal scales by assimilating radar, sounding, and satellite observations collected during DYNAMO. The DYNAMO observations of particular interest to the research are those from three Doppler radars, and those from an enhanced mesoscale sounding network. Major objectives of the research include: (1) exploring the most reliable and effective EnDA methods for tropical weather analysis and forecasts ranging from convective to regional scales by comparing different variational, ensemble-based and hybrid data assimilation approaches; (2) conducting convective- and regional-scale reanalysis using the most accurate and affordable EnDA method over the entire DYNAMO period, and verify with regular and field observations as well as existing global analysis or reanalysis; and (3) examining the dynamics and predictability of tropical weather and climate (including the MJO) from convective to intraseasonal scales using convection-permitting (i.e., very high temporal and spatial resolution) ensemble analysis and forecasting.Intellectual merits: The combination of the EnDA technique with field observations constitutes a potentially significant advance in data assimilation, and our understanding of the dynamics, evolution, prediction, and predictability of tropical weather and climate from convective to intraseasonal scales. The analysis and forecasts also provide an efficient pathway to bridge the understandings of tropical weather and climate from convective to intraseasonal scales.Broader impacts: The research efforts will provide educational benefits through the extensive participation of a doctoral graduate student and a postdoctoral scientist. Research findings will also be directly used in classroom teaching and for directing undergraduate research projects. The findings on the initialization, prediction, and predictability of MJO events will improve operational forecasts of tropical weather and climate, providing a direct benefit to the general public, whether they live in the tropics or in areas around the world that are affected by MJO events. The EnDA systems developed from this support, and the reanalysis of DYNAMO observations by WRF simulations, will be made freely available online with ample documentation to benefit the larger academic community.