Atmospheric Sounding Network in the Dynamics of the Madden-Julian Oscillation Project (DYNAMO)

马登-朱利安涛动动力学 (DYNAMO) 实地活动是 2011 年底/2012 年初在印度洋进行的一项国际实验——印度洋季节内变率合作实验 (CINDY2011) 的美国组成部分。 DYNAMO 的总体目标是加快对印度洋 MJO 启动关键过程的理解，并改进 MJO 的模拟和预测。 现场活动将包括多个雷达、大气探测站点、一架研究飞机、多艘研究船和海洋测量。 DYNAMO 的三个主要假设是： 1）只有当潮湿层在 MJO 尺度区域上变得足够深时，深层对流才能组织成 MJO 对流包层；这种湿润发生的速度决定了爆发前状态的持续时间，2）不同阶段的特定对流群体对于 MJO 启动至关重要，3）屏障层、风和剪切驱动的混合、浅温跃层和混合层夹带都通过控制上层海洋热含量和海表温度，从而控制表面通量反馈，在印度洋 MJO 启动中发挥着重要作用。以及后续的质量控制和分析。 DYNAMO 探测网络将由四个地点组成：甘岛、迪戈加西亚岛和两艘研究船。 研究人员将为DYNAMO规划探空网络，建立探空数据监测系统，用于现场数据质量控制和快速查看产品的准备。 活动结束后，该团队将为 DYNAMO 建模社区准备大规模的强迫场，并进行涉及 MJO 生命周期中的发散和非绝热加热剖面以及边界层演化的诊断研究。 这些任务将有助于解决 DYNAMO 活动的假设 1 和假设 2。 除了主要的 DYNAMO 假设外，研究人员还确定了他们计划测试的另外两个假设：1）印度洋上空 MJO 的预爆发（湿润或预调节）阶段，而不是在对流层低层中表现出逐渐稳定的水分积累，其特征是水分场的逐步演化，这与不同云群的发展有关；2）印度洋中部的混合层深度及其特性海洋在 MJO 的时间尺度上发生变化，这些变化与 DYNAMO 期间观测到的不断变化的云和降水场有相应的关系。该研究的更广泛影响包括多名研究生参与实地活动和数据分析。 成功的 DYNAMO 活动将提高对热带对流、MJO 的可预测性以及 MJO 对美国和其他地区天气的下游影响的了解。

The Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign is the US component of an international experiment in late 2011/early 2012 in the Indian Ocean, the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY2011). The overarching goal of DYNAMO is to expedite understanding of processes key to MJO initiation over the Indian Ocean and to improve simulation and prediction of the MJO. The field campaign will include multiple radars, atmospheric sounding sites, a research aircraft, multiple research vessels, and oceanic measurements. The three main hypotheses of DYNAMO are: 1) 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; the pace at which this moistening occurs determines the duration of the pre-onset state, 2) Specific convective populations at different stages are essential to MJO initiation, and 3) The barrier layer, wind- and shear-driven mixing, shallow thermocline, and mixing-layer entrainment all play essential roles in MJO initiation in the Indian Ocean by controlling the upper-ocean heat content and SST, and thereby surface flux feedbackThis award is for planning and implementation of the sounding network for DYNAMO, as well as follow up quality control and analysis. The DYNAMO sounding network will consist of four locations: Gan, Diego Garcia, and two research vessels. The researchers will plan the sounding network for DYNAMO and establish a sounding data monitoring system which will be used for field quality control of the data and preparation of quick-look products. After the campaign, the team will prepare large-scale forcing fields for the DYNAMO modeling community, as well as conduct diagnostic studies involving the divergence and diabatic heating profiles and the boundary layer evolution through the life cycle of the MJO. These tasks will help to address Hypotheses 1 and 2 of the DYNAMO campaign. In addition to the overarching DYNAMO hypotheses, the researchers have identified two others that they plan to test: 1) The pre-onset (moistening or pre-conditioning) phase of the MJO over the Indian Ocean, rather than exhibiting a gradual, steady build-up of moisture in the lower troposphere, is characterized by a stepwise evolution of the moisture field, which is related to the development of distinct cloud populations, and 2) The mixed-layer depth and its properties over the central Indian Ocean vary on the timescale of the MJO and these variations have corresponding relationships to the evolving cloud and precipitation fields observed during DYNAMO.The broader impacts of the research include the involvement of multiple graduate students in the field campaign and data analysis. A successful DYNAMO campaign would lead to improved understanding of tropical convection, the predictability of the MJO, and downstream effects of the MJO on weather in the United States and other areas.