A Postdoctoral Scientist to Synthesize Proxy Records of Arctic Holocene Climate

该基金将支持一名博士后研究人员开发全新世北极地区气候变率代理气候记录的主要新合成，并将气候重建与气候模型模拟进行比较。这一综合将建立在目前由研究小组研究过去8000年记录的代用气候记录的基础上。数据模型的比较将来自于NCAR最新的瞬态气候模拟。美国的社区气候系统模式（CCSM3），以及计划在2012年进行的新模式实验的结果。正如igbp -过去全球变化（PAGES）项目领导的两项正在进行的国际努力所设想的那样，该项目产生的北极气候重建将被整合到来自全球各地的类似综合中。的吗?两年吗?那么？SynTraCE吗?项目。知识价值。根据其背景和职业目标，博士后科学家将在以下研究问题中进行选择：(1)北极地区从全新世热极大期（HTM）到新冰川期（5000 - 3000年前）的气候过渡是否均匀？描述这一重大气候转变的时空格局对于评估气候变化在多大程度上是由海洋-大气环流引起的温度动态再分布与整个北极平均气候状态变化的结果是必要的。(2)与世界其他地方相比，北极的新冰期降温是否被放大了？评估北极的降温幅度对于理解与北极放大相关的反馈是必要的。(3)从热媒到新冰期的冷却纬向梯度与SynTraCE实验中CCSM3模拟的进动强迫驱动的冷却纬向梯度相比如何？量化这种梯度为数据模型比较提供了一个直接的目标。(4)从北极地区几十年到几个世纪的代用记录中重建的气候变率的幅度和模式是否与CCSM3 SynTraCE实验模拟的变率一致？分析代理资料和模式模拟的主要变率模态对于确定气候变化在多大程度上可以合理地归因于已知大气-海洋环流模态的自然变率是必要的。(5)可用的气候系统模拟的输出在哪些方面可以用作环境变化机制模式的边界条件，以近似驱动代理指标的过程？开发新的？inverse-proxy模型?预测气候变化如何驱动冰川范围、降水氧同位素值和北极湖泊初级生产力等代理指标是必要的，以避免基于经典回归的气候重建方法的主要假设。更广泛的影响。该项目将有助于了解气候变化，这是社会面临的一个关键挑战。这些结果将为验证气候模式和提高其准确模拟非线性变化的能力提供基准。改进未来气候预测模型将有助于？气候变率与变化？美国气候变化科学计划的主要项目组成部分。本提案的全部资金要求是支持博士后科学家（PS）。这位职业生涯早期的科学家将作为国际跨学科气候科学家团队的一部分接受第一手培训。学生将学习广泛的数据和基于模型的方法来研究北极和全球气候变化。在2011年秋冬期间，PS将在瑞士伯尔尼的PAGES国际项目办公室工作，PI将作为客座科学家在那里工作，他们将在那里与一个国际小组进行代理记录的综合研究。PS还将与科罗拉多州博尔德NCAR的气候建模师合作，在那里他/她将学习分析气候模型模拟的输出。在NAU， PS将被整合到PI的全部广度中。该计划包括一个活跃的分析实验室和实地研究计划。此外，还将鼓励私人教师定期帮助教授本科和研究生课程，以提高其教学技能。

This grant will support a post-doctoral investigator to develop a major new synthesis of proxy climate records of Holocene climate variability from across the Arctic, and compare the climate reconstruction with climate model simulations. The synthesis will build on proxy climate records currently being developed by teams of researchers looking at the past 8000 years of records. The data-model comparison will draw from newly available transient climate simulations by NCAR?s Community Climate System Model (CCSM3), and from the output of new model experiments planned for 2012. The Arctic climate reconstructions generated by this project will be integrated into similar syntheses from across the globe, as envisioned by two on-going international efforts led by the IGBP-Past Global Changes (PAGES) program ? the ?Two Millennia? and the ?SynTraCE? projects.Intellectual Merit. Depending on her/his background and career goals, the postdoctoral scientist will choose among the following research questions: (1) Was the climate transition from the Holocene thermal maximum (HTM) to the Neoglacial (5000 to 3000 years ago) uniform across the Arctic? Describing the spatial-temporal pattern of this major climate transition is necessary to assess the extent to which the climatic shift was the result of a dynamical redistribution of temperature by ocean-atmosphere circulation versus a shift in the mean state of climate across the Arctic. (2) Was Neoglacial cooling amplified in the Arctic compared with elsewhere around the world? Assessing the magnitude of cooling in the Arctic is necessary to understand the feedbacks associated with arctic amplification. (3) How does the latitudinal gradient of cooling from the HTM to the Neoglacial compare with the gradient of cooling driven by precessional forcing as simulated by CCSM3 in the SynTraCE experiment? Quantifying this gradient provides a straightforward target for a data-model comparison. (4) Are the magnitude and pattern of climate variability that are reconstructed from proxy records on timescales of decades to centuries from across the Arctic consistent with the variability simulated in CCSM3 SynTraCE experiment? Analyzing the principal modes of variability in both the proxy data and the model simulation is necessary to determine the extent to which climatic changes can reasonably be attributed to natural variability of known modes of atmospheric-ocean circulation. (5) In what ways can the output of available climate system simulations be used as boundary conditions in mechanistic models of environmental change that approximate the processes that drive the proxy indictors? Developing new ?inverse-proxy models? to predict how climate change drives proxy indicators such as glacier extent, oxygen-isotope values of precipitation, and primary productivity of Arctic lakes is necessary to avoid major assumptions that underlie classical regression-based approaches to climate reconstructions.Broader Impact. This project will contribute to understanding climatic variability, a key challenge facing society. The results will provide benchmarks for validating climate models and for improving their ability to accurately simulate nonlinear change. Improving models for future climate projections will contribute to the ?Climate Variability and Change? major program element of the US Climate Change Science Program. The entire funding request for this proposal is to support a postdoctoral scientist (PS). This early-career scientist will receive first- hand training as part of an international, interdisciplinary team of climate scientists. S/he will learn about a broad range of both data and model-based approaches to studying Arctic and global climate change. During the fall/winter of 2011, the PS will work at the PAGES International Project Office in Bern Switzerland, where the PI is scheduled as a Guest Scientist and where they will be well situated to engage an international group in a synthesis of proxy records. The PS will also work with climate modelers at NCAR in Boulder, Colorado where s/he will learn to analyze the output of climate model simulations. At NAU, the PS will be integrated into the full breadth of the PI?s research program, which includes an active analytical laboratory and field research program. The PS also will be encouraged to help regularly teach undergraduate and graduate courses to improve his/her teaching skills.