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.

该项目旨在调查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，而赤道东太平洋的特点是寒冷、营养丰富的深层沃茨的强烈上涌，称为太平洋冷舌。太平洋暖池和冷舌的演变对控制环太平洋气候和影响地球仪具有重要意义。其中一个周期是由热带辐合带（ITCZ）的季节性迁移驱动的，最终与由于地轴倾斜而导致的太阳辐射的季节和纬度分布有关-“倾斜”效应。虽然这种“倾斜”效应的年周期已被广泛研究，其他“距离”效应则较少。距离效应是由步行者环流强度的季节性变化引起的，并受地球轨道偏心率引起的地日距离的年变化的影响。本研究计划将探讨距离效应如何影响地球气候，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具有不成比例的大影响的区域，包括南太平洋的西风带;和3）热带太平洋平均状态和厄尔尼诺南方涛动（ENSO）。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理解。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。