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Nonlinear Dynamics of Daily-weekly Boreal Spring InterTropical Convergence Zone (ITCZ) Shifts over the Eastern Pacific Ocean

东太平洋上空北春季热带辐合带（ITCZ）日周变化的非线性动力学

基本信息

批准号：
1953944
负责人：
William Gutowski
金额：
$ 31.59万
依托单位：
Iowa State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-01 至 2024-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1953944&HistoricalAwards=false
关键词：
Nonlinear Dynamics Daily weekly Boreal

项目摘要

Textbook diagrams of the world's wind patterns show a narrow band around the equator where the tradewinds of the Northern and Southern Hemispheres flow together, causing rising motions, deep clouds, and heavy rain. This simple, static picture has served as a powerful conceptual framework to explain the existence of the band, know as the Intertropical Convergence Zone (ITCZ), and its connection to the global atmospheric circulation and the energy balance of earth's climate. But the real-world ITCZ is not static, and while theories developed from the static picture can account for its north-south seasonal migration and longer-term shifts accompanying ice ages, they may lack key ingredients needed to explain short-term ITCZ variability.Work performed here focuses specifically on the dynamics of short-term ITCZ fluctuations identified in a recent study of the Eastern Pacific in Northern Hemisphere Spring (Haffke et al 2016). The fluctuations include shifts from the Northern to the Southern Hemisphere and splitting events in which a single ITCZ is replaced by a pair of convergence zones, one on either side of the equator. The shifts and splits take place over the course of a few days and the project seeks to account for them in terms of changes in the winds of the atmospheric boundary layer (ABL, the lowest kilometer or so of the atmosphere). The Principal Investigator (PI) hypothesizes that these fluctuations are driven by relatively subtle changes in the large-scale pressure gradients affecting the region of the ITCZ. The pressure gradients lead to changes in the north-south component of the ABL winds near the equator, and the nonlinear advection of moisture and meridional momentum by these winds causes rapid ITCZ shifting or splitting. This hypothesis is tested and explored through a combination of observational analysis, focused on the longitudinally averaged ABL momentum equation, and idealized computer simulations.The broader impacts of the work include educational activity conducted through Iowa State University's Research Experiences for Teachers (RET) program targeted at middle and high school science teachers. Teachers from central Iowa schools participate in research related to this project over six summer weeks and also participate in a seminar series and regular discussion group on the pedagogy of science teaching. Later in the project the PI and students from his department visit the schools of the teachers in the program for all-day events devoted to the science of weather and climate. The events include presentations and hands-on activities, some using rotating tanks to demonstrate the dynamics of weather systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

教科书上的世界风模式图显示，赤道周围有一条狭窄的带，北方和南半球的信风在那里汇合，造成上升运动、厚云和大雨。这张简单的静态图片作为一个强有力的概念框架，解释了热带辐合带（ITCZ）的存在，以及它与全球大气环流和地球气候能量平衡的关系。但是，现实世界中的ITCZ并不是静态的，虽然从静态图像发展出来的理论可以解释它的南北季节性迁移和伴随冰河时代的长期变化，它们可能缺乏解释ITCZ短期变化所需的关键成分，这里所做的工作主要集中在最近对东太平洋在北方春季的研究中所确定的ITCZ短期波动的动力学上（Haffke et al 2016）。波动包括从北方到南半球的转移和分裂事件，其中一个单一的ITCZ被一对辐合区所取代，赤道两侧各有一个。这些变化和分裂发生在几天的过程中，该项目试图根据大气边界层（ABL，大气层的最低公里左右）的风的变化来解释它们。主要研究者（PI）假设这些波动是由影响ITCZ区域的大规模压力梯度的相对细微变化驱动的。压力梯度导致赤道附近ABL风的南北分量的变化，这些风的非线性平流的水分和纬向动量导致快速ITCZ移位或分裂。这一假设的测试和探索，通过结合观测分析，侧重于纵向平均ABL动量方程，和理想化的计算机simulation.The更广泛的影响，包括教育活动进行通过爱荷华州州立大学的教师研究经验（RET）计划针对初中和高中科学教师。来自爱荷华州中部学校的教师在六个夏季周内参加与该项目有关的研究，并参加关于科学教学法的系列研讨会和定期讨论组。在项目后期，PI和他所在系的学生参观了该项目教师的学校，参加了全天致力于天气和气候科学的活动。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Rapid Dynamical Evolution of ITCZ Events over the East Pacific

东太平洋 ITCZ 事件的快速动态演化

DOI：
10.1175/jcli-d-21-0216.1
发表时间：
2022
期刊：
Journal of Climate
影响因子：
4.9
作者：
Gonzalez, Alex O.;Ganguly, Indrani;McGraw, Marie C.;Larson, James G.
通讯作者：
Larson, James G.

Dynamical Importance of the Trade Wind Inversion in Suppressing the Southeast Pacific ITCZ

信风逆温对抑制东南太平洋 ITCZ 的动力学重要性

DOI：
10.1029/2023jd039571
发表时间：
2024
期刊：
Journal of Geophysical Research: Atmospheres
影响因子：
0
作者：
Gonzalez, Alex O.;Ganguly, Indrani;Osterloh, Marissa;Cesana, Gregory V.;DeMott, Charlotte A.
通讯作者：
DeMott, Charlotte A.

The Relationship between Convectively Coupled Waves and the East Pacific ITCZ

对流耦合波与东太平洋 ITCZ 的关系