Collaborative Research: Dynamics of the MJO (DYNAMO) Scientific Program Overview

合作研究：MJO (DYNAMO) 动力学科学计划概述

• 批准号: 1022899
• 负责人: Chidong Zhang
• 金额: $ 0.76万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1022899&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamics; MJO; DYNAMO

This is an award to support continued planning for DYNAMO. It is not a commitment by NSF to fund the field project and related analysis and numerical simulation work. Those funding decisions will be determined by means of further review.The Dynamics of the Madden-Julian Oscillation (DYNAMO) project is a field campaign to study the iniitiation of the Madden-Julian Oscillation (MJO), followed by a suite of data analysis, modeling, and forecasting studies. The MJO is an envelope of organized convection that propagates from the Indian Ocean to the Pacific Ocean and constitutes the dominant form of intraseasonal precipitation and atmospheric circulation variability in the tropics. The MJO influences a variety of tropical weather and climate phenomena,including tropical cyclones (affecting hurricanes in the Gulf of Mexico), the onset and intraseasonal fluctuations of the monsoons and rainfall over Asia, Australia, Africa, and the Americas, and the onset of El Nino events. Despite its importance and concerted efforts over several decades, the MJO has not yet been adequately explained, and global atmospheric circulation models have difficulty simulating and predicting it.The field campaign is planned for October 2011 to March 2012, to take advantage of an international effort known as the Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011 (CINDY2011). The DYNAMO observing array would take the form of a quadrangle observing array consisting of two ships and two islands. The islands are Diego Garcia (approximately 7S, 72E) and Gan, the southernmost island of the Maldive chain (near 0S, 73E). The ships would be located roughly 10 degrees east of the islands, and one ship station would held by a US research vessel (RV) while the other would be held alternately by RVs from Japan, Australia, and India. The RVs collect atmospheric and oceanographic observations using a combination of moored buoys, ship-based air-sea flux measurements, radars, and radiosonde launches. A radar "supersite" including radars of varying wavelengths, is planned for Gan, in addition to radiosonde launches on the island. Diego Garcia provides radiosonde launches to allow a four point observing array which can be used to compute the convergence of atmospheric heat and moisture fluxes.The DYNAMO project seeks to test three general hypotheses regarding the initiation of the MJO, which focus on the interaction between convection and environmental moisture, the evolution of cloud populations, and air-sea interaction. The first hypothesis is that "Deep convection can be organized into an MJO convective envelope only when the moist layer has become sufficiently deep over a region of the MJO scale, and the pace at which this moistening occurs determines the duration of the pre-onset state. The second hypothesis is that specific convective cloud populations at different stages are essential to MJO initiation. Clouds are considered to play two roles, one as a moistening agent through detrainment and the other as a driver of large-scale circulation through diabatic heating. The third hypothesis is that air-sea interactions and ocean conditions play an essential role in the initiation of the MJO, particularly in establishing the tropical Indian Ocean as the locus of MJO onset.The project aims to improve the ability of numerical models to provide forecasts of MJO activity, which would be of great societal benefit due to the connections between the MJO and fluctuations of weather and climate (including hurricanes). DYNAMO would also have a strong educational benefit by introducing young scientists, including graduate students, to the tropical meteorology and oceanogaphy of the Indian Ocean. A field campaign on the scale of DYNAMO has not previously been carried out in the Indian Ocean, and the data collected during the campaign would be beneficial for a variety of purposes, including improvements to convective parameterization in climate models and the calibration and validation of satellite retrievals.

这是一个支持迪纳摩继续规划的奖项。NSF并没有承诺为实地项目以及相关的分析和数值模拟工作提供资金。马登-朱利安振荡的动力学(Dynamo)项目是一个实地活动，旨在研究马登-朱利安振荡(MJO)的启动，随后是一系列数据分析、建模和预测研究。MJO是从印度洋传播到太平洋的有组织对流的包层，构成了热带地区季节内降水和大气环流变率的主要形式。MJO影响各种热带天气和气候现象，包括热带气旋(影响墨西哥湾的飓风)、亚洲、澳大利亚、非洲和美洲的季风和降雨量的开始和季节内波动，以及厄尔尼诺事件的开始。尽管MJO很重要，经过几十年的共同努力，但MJO尚未得到充分解释，全球大气环流模型也难以模拟和预测它。实地活动计划于2011年10月至2012年3月进行，以利用名为2011年印度洋季节内变化合作实验(CINDY2011)的国际努力。发电机观测阵列将采取由两艘船和两个岛屿组成的四边形观测阵列的形式。这些岛屿是迭戈·加西亚(约7度，东经72度)和甘岛，马尔代夫群岛最南端的岛屿(近0度，东经73度)。这些船只将位于岛屿以东约10度处，一个船站将由一艘美国科考船(RV)持有，另一个将由来自日本、澳大利亚和印度的房车交替持有。房车使用系泊浮标、基于船舶的海气通量测量、雷达和无线电探空仪发射的组合来收集大气和海洋观测。除了在岛上发射无线电探空仪外，甘肃还计划建设一个包括不同波长雷达在内的雷达“超级站点”。迭戈·加西亚提供无线电探空仪发射，以允许一个四点观测阵列用于计算大气热通量和水汽通量的辐合。迪纳摩项目试图检验关于MJO启动的三个一般假设，重点是对流和环境水汽之间的相互作用，云群的演变，以及海-气相互作用。第一个假设是“只有当湿润层在MJO尺度的区域变得足够深时，才能将深层对流组织成MJO对流包层，而这种增湿发生的速度决定了预发状态的持续时间。第二个假设是，不同阶段的特定对流云群对MJO的形成是必不可少的。云被认为起着两种作用，一种是通过脱旋起到润湿剂的作用，另一种是通过非绝热加热来驱动大范围环流。第三个假设是，海气相互作用和海洋条件在MJO的形成过程中起着重要作用，特别是在热带印度洋成为MJO中心的过程中。该项目旨在提高数值模式预测MJO活动的能力，由于MJO与天气和气候波动(包括飓风)之间的联系，这将具有很大的社会效益。迪纳摩还将通过向包括研究生在内的年轻科学家介绍印度洋的热带气象学和海洋学，从而产生巨大的教育效益。以前从未在印度洋开展过发电机规模的实地活动，活动期间收集的数据将有益于各种目的，包括改进气候模型中的对流参数化以及校准和验证卫星反演。