The Distance Effect Annual Cycle in Earth's Climate

地球气候的距离效应年周期

• 批准号: 2303385
• 负责人: John Chiang
• 金额: $ 55.63万
• 依托单位: University of California-Berkeley
• 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: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303385&HistoricalAwards=false
• 关键词: Distance; Effect; Annual; Cycle; Earth

This project aims to investigate the impact of two aspects of Earth’s orbital geometry on its climate. The Western Pacific Warm Pool of the tropical Pacific Ocean retains the largest and warmest sea surface water body on Earth while the eastern equatorial Pacific is characterized by strong upwelling of cold, nutrient-rich deep waters, termed the Pacific cold tongue. Understanding the evolution of the Pacific warm pool and cold tongue are important because they control the circum-Pacific climate and impact the globe via El Nino-Southern Oscillation (ENSO) teleconnections.Previous research indicates that the Pacific cold tongue has two annual cycles driven by distinct features of the Earth’s orbit. One of these cycles is driven by the seasonal migration of the InterTropical Convergence Zone (ITCZ) and is ultimately linked to the seasonal and latitudinal distribution of solar insolation due to the tilt of the Earth’s axis – the “tilt” effect. While this “tilt” effect annual cycle has been extensively studied, the other “distance” effect is less so. It is argued that the “distance” effect arises from seasonal variations in the strength of the Walker circulation and is forced by the annual evolution of the Earth-Sun distance due to the eccentricity of Earth’s orbit.This research project will investigate how the distance effect imprints its climate influence on Earth, specifically on the: 1) distance-effect seasonality of the atmospheric general circulation; 2) seasonality of regional climates, choosing regions where the distance effect has a disproportionately large impact relative to tilt, including the westerlies over the South Pacific; and 3) tropical Pacific mean state and El Nino-Southern Oscillation (ENSO).The potential Broader Impacts (B.I.) include support for graduate and undergraduate students, public outreach, and a more comprehensive understanding of climate with important societal impacts.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.

该项目旨在研究地球轨道几何形状的两个方面对其气候的影响。热带太平洋的西太平洋暖池保留了地球上最大和最温暖的海表水体，而东赤道太平洋的特点是强烈的上升流。寒冷、营养丰富的深水，称为太平洋冷舌，了解太平洋暖池和冷舌的演变非常重要，因为它们控制环太平洋气候并通过厄尔尼诺南方涛动（ENSO）影响全球。先前的研究表明，太平洋冷舌有两个由地球轨道的独特特征驱动的年度周期，其中一个周期是由热带辐合带（ITCZ）的季节性迁移驱动的，并且最终与季节和纬度相关。由于地轴倾斜而导致的太阳辐射分布——“倾斜”效应虽然这种“倾斜”效应年周期已得到广泛研究，但另一种“距离”效应却较少研究。有人认为，“距离”效应是由沃克环流强度的季节性变化引起的，并且是由于地球轨道偏心率导致的地日距离的年度演变所迫使的。该研究项目将研究距离效应如何产生影响它对地球的气候影响，特别是：1）大气环流的距离效应季节性；2）区域气候的季节性，选择距离效应相对于倾斜度具有不成比例的巨大影响的区域，包括南部的西风带。太平洋；3) 热带太平洋平均状态和厄尔尼诺-南方涛动 (ENSO)。潜在的更广泛影响 (B.I.) 包括对研究生和本科生的支持、公众宣传以及对具有重要社会影响的气候的更全面的了解。授予 NSF 的法定使命，并通过评估反映使用基金会的智力优点和更广泛的影响审查标准，被认为值得支持。