Radar Observations of the Cloud Population in the Developing Madden-Julian Oscillation

Madden-Julian Oscillation（MSTO）现场活动的动力学是2011年底/2012年初在印度洋进行的国际实验的美国组成部分，该实验是印度洋季节内变率合作实验（CINDY 2011）。 该项目的总体目标是加快对印度洋MJO启动的关键过程的理解，并改进MJO的模拟和预测。 实地活动将包括多个雷达、大气探测站、一架研究飞机、多艘研究船和海洋测量。 MJO的三个主要假设是：（1）只有当湿层在MJO尺度上变得足够深时，深对流才能组织成MJO对流包层;这种润湿发生的速度决定了预开始状态的持续时间，2）不同阶段的特定对流群体对于MJO的开始是必要的，和3）阻挡层，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SST，从而控制表面通量反馈，在印度洋MJO的形成中发挥着重要作用。 这些数据将与补充观测数据相结合，以获得云量和湿度场的关键经验特征，从而有助于检验气象卫星的假设1和2。 S-PolKa部署将由该研究团队领导。 该研究由四个主要部分组成：1）使用现有的雷达数据来解决假设II，通过显示每种类型的云有多少构成完整的云群，以及这些不同的云联合收割机如何组合以产生净加热，水分和动量反馈，因为MJO启动从发病前，发病，发病后阶段的进展。2)获得的数据，显示如何的MJO云人口的特点，在湿度场的充电过程中，通过仔细检查云之间的直接接口和发展中的环境湿度分布在每个初始阶段和阶段之间的过渡演变。3)通过比较几种模型对MJO启动期间云群的描述来检查它们的性能。4)确定MJO初始云量与海洋热带其他地区观察到的雷达回波云量是否一致或不同。这项工作的更广泛影响包括多名研究生参与实地研究，以及对MJO运动更广泛目标的贡献，以提高对热带对流的理解，MJO的可预测性，以及MJO对美国和其他地区天气的下游影响。

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 will allow for the collection and analysis of S-PolKa and other supersite radar data from the island of Gan. This data will be combined with complementary observational data to acquire key empirical characteristics of the populations of clouds and the humidity field to contribute to the testing of DYNAMO Hypotheses 1 and 2. The S-PolKa deployment during DYNAMO will be led by this research team. The study consists of four main parts: 1) Use of the available radar data to address Hypothesis II by showing how many clouds of each type make up the full cloud population, and how these different mixes of clouds combine to produce net heating, moisture, and momentum feedbacks as the MJO initiation progresses from the pre-onset, to onset, to post-onset stages. 2) Obtain data that show how the characteristics of the MJO cloud population evolve during the recharging of the humidity field by closely examining the direct interface between clouds and the developing environmental humidity profile in each of the initiation stages and in the transitions between stages. 3) Examine the performance of several models by comparing their depiction of the cloud population during the MJO initiation. 4) Establish whether the MJO initiation cloud population is consistent with or differs from radar echo populations observed in other parts of the oceanic tropics.The broader impacts of the work include the involvement of multiple graduate students in field research, and the contribution to the broader goals of the DYNAMO campaign to improve understanding of tropical convection, the predictability of the MJO, and downstream effects of the MJO on weather in the United States and other areas.