Collaborative Research: Late Holocene Climate Variability From Stable Isotope Ratio Analysis of Coast Redwood Tree Ring Cellulose

该项目旨在探索树木所记录的大气湿度与气候之间的关系。研究人员假设，雾是美国太平洋海岸海洋-陆地-大气界面年际夏季气候变化的一个强有力的综合测量。他们进一步表明，沿海风、海面温度（SSTs）、陆地温度和太平洋年代际振荡（PDO）之间存在很强的耦合。该研究的主要目的是评估同位素记录中高频（厄尔尼诺-南方涛动尺度）和多年代际（PDO）变率的性质变化，并提供有关美国太平洋沿岸小冰期和中世纪气候异常特征的新信息。研究人员认为，加利福尼亚北部沿海地区的气候为利用树木年轮的稳定同位素恢复一种新的高分辨率古气候记录奠定了基础。他们建议将注意力集中在海岸红木（Sequoia sempervirens）上。唐[Endl.])，一种长寿的树种，有些个体的年龄超过2000年。研究人员假设，对古代红木年轮的稳定同位素分析可以提供过去1000年来大规模气候机制的年度解决代理信息，他们的目标是将暖季变化置于长期背景下，以便评估自然和人为变化的范围。这一假设是基于该团队之前的研究，该研究建立了重建气候的可行性，包括北加州春季和夏季的降水和雾，从美国太平洋海岸利用红木年轮纤维素的碳和氧的稳定同位素分析。他们的研究还表明，在过去的一个世纪里，加利福尼亚北部沿海的夏季气候发生了实质性的变化，包括雾频率减少了33%，沿海海温增加了0.8°C。更广泛的影响包括追求高风险的研究计划，这可能会产生一个从环境和生态数据重建气候的新视角。这项研究可能对包括气候学家和森林管理者在内的广泛用户有价值。该项目包括一个非博士学位授予机构和一个高性能的研究实验室之间的强有力的合作。

This project aims to explore the relationship between atmospheric moisture and climate as recorded in trees. The researchers postulate that fog is a strongly integrative measure of interannual summer climate variability at the ocean-land-atmosphere interface of the U.S. Pacific Coast. They further suggest that there is strong coupling to coastal wind, sea-surface temperatures (SSTs), land temperatures, and the Pacific Decadal Oscillation (PDO). The broad aim of the research is to assess changes in the nature of high-frequency (El Nino Southern Oscillation-scale) and multi-decadal (PDO) variability in the isotope records and to provide new information on the character of the Little Ice Age and Medieval Climate Anomaly on the U.S. Pacific coast. The researchers argue that the climate of coastal northern California sets the stage for recovering a novel high-resolution paleoclimate record using stable isotopes from tree-rings. They propose to focus their attention on the Coast Redwood (Sequoia sempervirens [D. Don] Endl.), a long-lived tree species, with some individuals exceeding 2,000 years in age. The researchers hypothesize that stable isotope analysis of ancient redwood tree rings could provide annually-resolved proxy information on large-scale climate mechanisms over the last 1,000 years and they aim to place warm-season changes in long-term context so that the range of natural and anthropogenic variations can be assessed.This hypothesis is based on the team's previous research that established the feasibility of reconstructing climate, including northern California precipitation and fog in the spring and summer seasons, from the U.S. Pacific coast using stable isotope analysis of carbon and oxygen of redwood tree-ring cellulose. Their research also shows that over the past century, coastal northern California summer climate has changed substantially, including a ~33% reduction in fog frequency and a coastal SST increase of ~0.8°C. The broader impacts involve pursuing a high risk research plan that could yield a new perspective on reconstructing climate from environmental and ecological data. The research could be of value to a broad range of users that include climatologists and forest managers. The project includes a strong collaboration between a non-PhD degree granting institution and a high performing research laboratory.