Variability of Tropical Elongated Convergence Zones

热带辐合区(ITCZ)是狭窄的、纬向拉长的降水增强区域，在所有大洋盆地的赤道附近，都可以在降水、云量和地面风辐合的时间平均曲线上找到。此外，一个被称为南太平洋辐合带(SPCZ)的平均降水增强的拉长区域横跨西太平洋延伸到赤道以南，有些向东南方向。该项目使用一种将应用于各种数据集的新的时空统计模型，包括最近可用的高分辨率30年卫星数据集，审查了这些特征的区域复盖率和位置的可变性。统计方法是马尔可夫随机场(MRF)模型，其基于ITCZ像素在空间和时间上的聚类来识别包含在ITCZ中的像素。MRF模式被用来检验由瞬变现象引起的ITCZ的变异性，包括东风波、温带扰动和Madden-Julian振荡(MJO)。关于温带扰动的影响的研究特别侧重于这些扰动在为“大气河流”中强烈的水分输送创造条件方面的作用。对东风波的研究试图确定这样的波的比例，这些波在没有相互作用的情况下通过ITCZ传播，进入ITCZ，或导致结构良好的ITCZ破裂。其他令人感兴趣的问题包括赤道两侧相互平行的双ITCZ的形成，这种现象在自然界中存在，但在许多气候模型中被大大夸大了，以及ITCZ与下垫面海表面温度之间的关系。除了MRF模式和其他观测诊断工具外，该项目还使用区域气候模式(RCM)来模拟ITCZ行为。ITCZ的行为具有重要的实践意义和理论意义，因为ITCZ的变化与厄尔尼诺事件、MJO和大气河流有关，所有这些都对美国的恶劣天气有影响。此外，这项工作还为两名研究生提供教育和培训，他们将接受大气科学和统计建模方面的培训，从而有助于发展一支跨学科的科学队伍。这两名学生还参加了一项针对中小学生的外展和教育项目，该项目被称为气候扫盲赋权和调查项目。

Intertropical convergence zones (ITCZs) are narrow, zonally elongated regions of enhanced precipitation which can be identified near the equator over all ocean basins in time-averaged plots of precipitation, cloudiness, and surface wind convergence. In addition, an elongated region of enhanced mean precipitation known as the South Pacific Convergence Zone (SPCZ) extends across the Western Pacific to the south of the equator, with a somewhat southeastward orientation. This project examines the variability in the aereal coverage and location of these features using a novel spatial-temporal statistical model that will be applied to various datasets including a recently available high-resolution 30-year satellite dataset. The statistical method is a Markov random field (MRF) model, which identifies pixels contained in an ITCZ based on the clustering of ITCZ pixels in space and time. The MRF model is used to examine the variability of ITCZs caused by transient phenomena including easterly waves, extratropical disturbances, and the Madden-Julian Oscillation (MJO). Research on the impact of extratropical disturbances focuses in particular on the role of these disturbances in creating the conditions for intense moisture transport in "atmospheric rivers". Research on easterly waves seeks to determine the proportions of such waves which propagate through an ITCZ without interaction, become immersed in the ITCZ, or result in the breakup of a well-formed ITCZ. Other issues of interest include the formation of double-ITCZs, parallel to each other on either side of the equator, which occur in nature but are greatly exaggerated in many climate models, and the relationship between ITCZs and underlying sea surface temperatures. In addition to the MRF model and other observational diagnostic tools, the project uses a regional climate model (RCM) to simulate ITCZ behavior.The behavior of ITCZs is of practical importance as well as theoretical interest, as ITCZ variability is associated with El Nino events, the MJO, and atmospheric rivers, all of which have implications for severe weather in the United States. In addition, the work provides education and training for two graduate students, who will be trained in both atmospheric science and statistical modeling, thereby contributing to the development of an interdisciplinary science workforce. The two students also participate in an outreach and education program for elementary and middle school children, known as the Climate Literacy Empowerment and iNquiry program.