Beyond Mean Climate: Quantifying Climate Variability and Extremes under Varying Boundary Conditions

超越平均气候：量化不同边界条件下的气候变化和极端情况

• 批准号: 2303149
• 负责人: Tyler Jones
• 金额: $ 123.78万
• 依托单位: University of Colorado at Boulder
• 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: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303149&HistoricalAwards=false
• 关键词: Beyond; Mean; Climate; Quantifying; Variability

The Earth’s climate can be defined broadly by two concepts, average values and variability around those averages; for example the average temperature of a location over some interval and how much the temperature varies from that average on any given day, or month, or year, or decade. This variability is important to human societies, driving things like extreme heat waves or droughts. Over Earth’s long history, the average climate has changed in profound ways. For example, 20,000 years ago, the Earth on average was about 5 degrees Celsius colder, and large glaciers covered parts of continents that are ice free today. We know that the average climate has changed because we have evidence from natural archives, such as that found in the chemistry of ice that remains frozen at the poles. But how has the variability changed? Does the variability change with the same pattern as the average? How often do extreme events - such as extremely hot or cold temperatures - occur at different times in the past? Records of the year–to-year or decade-to-decade variability, say from 20,000 years ago, are exceptionally rare. We will use climate records from very high-resolution measurements of ancient polar ice in Greenland and Antarctica, obtained through a process known as ‘ice coring’, to study the inherent variability in Earth’s climate and how it changes over long periods of time, extending backwards in time up to 100,000 years before present. These aspects of climate, the variability and extremes, in addition to the average climate, can provide new contexts that help us better understand our changing planet.The relationship between the mean climate and its internal variability is a fundamental aspect of climate dynamics. Understanding the dependence of internal variability on the mean state is key to understanding the detectability of forced changes in climate and, critically, the change in likelihood of extreme events. Information about internal climate variability throughout Earth’s history, as the mean climate has undergone large changes, such as during the Last Glacial Maximum about 20,000 years ago, is exceedingly rare. Most paleoclimate archives lack the detail or continuity to reliably resolve annual, interannual, and decadal timescales for tens of thousands of years. We will use a suite of five extremely high-resolution ice core records of water isotopes, as well as impurities like dust, to statistically catalog variability and extremes in polar climate and its relationship to the background mean state. We will examine these relationships over periods of stable mean climate, long term changes in global mean climate, as well as abrupt climate change, and provide an unprecedented analysis of high-frequency, high-latitude climate variability. The analysis will span the last glacial-interglacial cycle, extending backwards in time up to a 100,000 years into the past. High-frequency climate variability has been impactful to humans and societies throughout history. Annual, interannual, decadal, and centennial scale variability has driven changes in habitability leading to the blossoming and collapse of past civilizations. Extreme climate events in particular affect modern quality of life, national security, food and water availability, and ecosystem services (among other concerns). The proposed research on climate variability and extremes of the past, and the relationship to average climate, can provide new contexts that help us better understand our changing planet.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.

地球的气候可以通过两个概念，平均值的平均价值和可变性来广泛定义；例如，某个时间间隔的位置的平均温度以及温度的平均水平从任何给定的一天，或一个月或一年或十年的平均值不等。这种差异对人类社会很重要，驱动诸如极端热浪或干旱之类的事物。在地球悠久的历史上，平均攀登以深刻的方式发生了变化。例如，20，000年前，地球平均比摄氏5度更冷，而大型冰川覆盖了当今无冰的大陆部分。我们知道，平均气候发生了变化，因为我们有自然档案的证据，例如在冰的化学中发现的证据。但是变异性如何变化？变异性是否与平均值相同的模式变化？过去的不同时间发生极端事件（例如极度炎热或寒冷的温度）多久发生？年度的记录至年或十年至十年的变异性（例如20，000年前）异常罕见。我们将使用通过称为“冰芯”的过程获得的格陵兰和南极洲古代冰的高分辨率测量的气候记录，以研究地球气候中的继承变异性以及它在长时间内如何变化，并在现存前的时间延伸至100,000年。气候的这些方面，除了普通气候之外，可变性和极端的方面还可以提供新的环境，以帮助我们更好地了解我们的星球变化。平均攀岩与其内部变异性之间的关系是气候动态的基本方面。了解内部变异性对平均状态的依赖性是理解气候强迫变化以及极端事件可能性的变化的关键。关于整个地球历史的内部气候变化的信息，因为平均攀登的大幅变化，例如在大约20，000年前的最后一次冰川最大变化中，非常罕见。大多数古气候档案馆都缺乏可靠地解决年度，年际和十年时间尺度的细节或连续性。我们将使用五个非常高分辨率的水同位素的冰核记录以及诸如灰尘等杂质的套件，以统计学上的分类差异和极性气候的极端及其与背景平均状态的关系。我们将在稳定的平均气候，全球平均气候的长期变化以及突然的气候变化的时期内检查这些关系，并对高频，高纬度气候变异性提供前所未有的分析。分析将跨越最后的冰川间冰周期，并在过去的100，000年内向后延伸。在整个历史上，高频攀岩变异性对人类和社会都有影响。年度，年际，十年和百年尺度的变异性导致了宜居性的变化，导致过去文明的血液和崩溃。极端攀岩活动特别影响现代生活质量，国家安全，食品和水的可用性以及生态系统服务（包括其他问题）。关于气候变化和过去的极端以及与平均气候的关系的拟议研究可以提供新的环境，以帮助我们更好地了解不断变化的星球。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛的影响来通过评估来获得的支持。