Collaborative Research: Cloud-Radiative Feedback as the Coupling Mechanism of the Madden-Julian Oscillation and Quasi-Biennial Oscillation

合作研究：云辐射反馈作为马登-朱利安振荡和准两年振荡的耦合机制

• 批准号: 2303504
• 负责人: Angel Adames-Corraliza
• 金额: $ 33.69万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303504&HistoricalAwards=false
• 关键词: Collaborative; Research; Cloud; Radiative; Feedback

A remarkable feature of weather in the tropics is the occasional appearance of a vast region of cloudy conditions moving slowly eastward along the equator from the Indian Ocean to the Pacific, causing an alternation of rain and clear skies over a period of a month or two. This alternation, called the Madden-Julian Oscillation (MJO), has a variety of long-range influences, for instance it affects the chances of hurricanes in the Gulf of Mexico and landfalling atmospheric rivers along the California coast. Given its slow propagation and worldwide effects the MJO is the dominant driver of predictable weather and climate variations on the subseasonal timescale. Naturally the MJO has been a topic of intensive research since its discovery in 1971 but we still lack a satisfactory understanding of it, and models used for weather predictions and climate simulations have difficulty representing it.One mystery of the MJO is its dependence on the direction of the stratospheric winds above it, which changes from easterly to westerly in a somewhat regular progression referred as the Quasi-Biennial Oscillation (QBO). The MJO is substantially more active in the easterly phase of the QBO, which features colder temperatures in the equatorial lower stratosphere along with the easterly winds. Some researchers have argued that the colder temperatures promote the MJO by reducing upper tropospheric stability and thus strengthening MJO-related convection. But the Principal Investigators (PIs) of this award hypothesize that colder temperatures matter because they promote cirrus clouds, which favor the MJO due to their infrared radiative feedback. The cirrus cloud hypothesis is motivated by several aspects of the QBO influence, among them that the influence does not appear prior to 1980. The 1980 onset makes sense because the stratosphere was warmer prior to 1980 and thus cirrus clouds would have been less susceptible to the cooling effect of the easterly QBO phase. The QBO-MJO relationship is explored through a variety of activities including analysis of data from several satellite missions (including COSMIC, CALYPSO, MLS) and reanalysis datasets, climate model simulations, and a simple linear model (based on the one used in AGS-2201441).The work is of societal as well as scientific value given the influence of the MJO on weather around the world and the possibility that the MJO could be predictable given better understanding of its behavior. The PIs conduct a webinar series to exchange research results with the MJO research community, and the lead PI is developing an online Spanish language workshop on the role of cloud processes in weather and climate. In addition, the project provide support and training to two graduate students.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.

热带地区天气的一个显着特征是，偶尔出现大片多云天气，沿着赤道从印度洋向太平洋缓慢向东移动，导致在一两个月的时间内降雨和晴空交替。 这种交替被称为马登-朱利安振荡（MJO），具有多种远程影响，例如它会影响墨西哥湾飓风和加利福尼亚海岸大气河流登陆的可能性。 鉴于其缓慢的传播和全球影响，MJO 是次季节时间尺度上可预测天气和气候变化的主要驱动因素。当然，自 1971 年被发现以来，MJO 一直是一个深入研究的话题，但我们仍然对它缺乏令人满意的了解，用于天气预报和气候模拟的模型也很难代表它。MJO 的一个谜团是它依赖于其上方平流层风的方向，平流层风以一种称为准两年振荡 (QBO) 的有规律的进程从东风转向西风。 MJO 在 QBO 的东相期间更加活跃，其特点是赤道低平流层温度较低且有东风。 一些研究人员认为，较低的温度会降低对流层上层的稳定性，从而加强与 MJO 相关的对流，从而促进 MJO 的发生。 但该奖项的首席研究员 (PI) 假设，较冷的温度很重要，因为它们会促进卷云，而卷云由于其红外辐射反馈而有利于 MJO。 卷云假说是由 QBO 影响的几个方面推动的，其中这种影响在 1980 年之前不会出现。1980 年的爆发是有道理的，因为平流层在 1980 年之前较温暖，因此卷云不太容易受到东面 QBO 阶段的冷却效应的影响。 通过各种活动探索了 QBO-MJO 关系，包括分析来自多个卫星任务（包括 COSMIC、CALYPSO、MLS）的数据和再分析数据集、气候模型模拟和简单的线性模型（基于 AGS-2201441 中使用的模型）。鉴于 MJO 对世界各地天气的影响以及通过更好地了解 MJO 可以预测的可能性，这项工作具有社会和科学价值。 它的行为。 PI 举办了一系列网络研讨会，与 MJO 研究界交流研究成果，首席 PI 正在开发一个关于云过程在天气和气候中的作用的在线西班牙语研讨会。 此外，该项目还为两名研究生提供支持和培训。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。