AGS-PRF: Understanding Historical Trends in Tropical Pacific Sea Surface Temperature Patterns

AGS-PRF：了解热带太平洋海面温度模式的历史趋势

• 批准号: 2317224
• 负责人: Allison Hogikyan
• 金额: $ 20.2万
• 依托单位: Hogikyan, Allison
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2317224&HistoricalAwards=false
• 关键词: AGS; PRF; Understanding; Historical; Trends

Warming sea surface temperatures (SSTs) are an expected consequence of rising greenhouse gas levels, and the past several decades have seen a dramatic increase in global SST. But the eastern tropical Pacific has not warmed as expected despite substantial West Pacific warming. The reasons for the absence of East Pacific warming are not clear and the lack of warming stands in contrast to the SST trend patterns in model simulations, which typically show an El Nino-like pattern with greater warming to the east. The opposition between observed and simulated Pacific trend patterns has attracted considerable interest among climate scientists, as the warming pattern matters for both regional climate impacts and the overall amount of warming caused by greenhouse gas increases.Research conducted here seeks to understand the physical mechanisms that account for the difference in Pacific warming patterns between simulations and observations. The project involves comparisons between full-complexity climate models and the Zebiak-Cane (ZC) model, a highly idealized atmosphere-ocean model built to capture the basic dynamics of El Nino. The model produces an SST trend pattern similar to the observations and thus provides an important point of reference for understanding the physical mechanisms that produce the pattern. The work involves adding mechanisms to the ZC model and disabling the same mechanisms in a full-complexity climate model to understand the effects of particular mechanisms. A key consideration is the role of mean state bias in the simulated pattern, as earlier work suggests that simulations produce an incorrect trend pattern due to a well-known "cold tongue" bias in which the strip of cold SST along the eastern equatorial Pacific is too long and too cold.The work is of practical as well as scientific interest due to the implications of the SST pattern for regional climate impacts. These include the distribution and intensity of Pacific tropical cyclones (hurricanes and typhoons) and the effect of Pacific warming on drought in the US Southwest. In addition, the award provides for the career development of a Postdoctoral Research Fellow (PRF), who will work with mentors Tiffany Shaw and Malte Jansen at the University of Chicago.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.

海面温度（SST）变暖是温室气体水平上升的预期后果，过去几十年来，全球海表温度急剧增加。 但尽管西太平洋大幅变暖，但东热带太平洋并未像预期那样变暖。 东太平洋没有变暖的原因尚不清楚，而且没有变暖与模型模拟中的海温趋势模式形成鲜明对比，模型模拟通常显示出类似厄尔尼诺的模式，东部变暖幅度更大。 观测到的和模拟的太平洋趋势模式之间的对立引起了气候科学家的极大兴趣，因为变暖模式对于区域气候影响和温室气体增加引起的总体变暖量都很重要。这里进行的研究旨在了解解释这一现象的物理机制模拟和观测之间太平洋变暖模式的差异。 该项目涉及完全复杂的气候模型和 Zebiak-Cane (ZC) 模型之间的比较，Zebiak-Cane (ZC) 模型是一种高度理想化的大气-海洋模型，旨在捕捉厄尔尼诺现象的基本动态。 该模型产生了与观测结果相似的海温趋势模式，从而为理解产生该模式的物理机制提供了重要的参考。 这项工作包括向 ZC 模型添加机制，并在完全复杂的气候模型中禁用相同的机制，以了解特定机制的影响。 一个关键的考虑因素是平均状态偏差在模拟模式中的作用，因为早期的研究表明，由于众所周知的“冷舌”偏差，模拟产生了不正确的趋势模式，其中沿赤道东太平洋的冷海温带是太长、太冷。由于海温模式对区域气候影响的影响，这项工作具有实际意义和科学意义。 其中包括太平洋热带气旋（飓风和台风）的分布和强度以及太平洋变暖对美国西南部干旱的影响。 此外，该奖项还为一名博士后研究员（PRF）的职业发展提供了支持，该研究员将与芝加哥大学的导师蒂芙尼·肖（Tiffany Shaw）和马尔特·詹森（Malte Jansen）一起工作。该奖项反映了 NSF 的法定使命，经评估认为值得支持利用基金会的智力优势和更广泛的影响审查标准。