Collaborative Research: Pliocene and Pleistocene transient climate simulations and model-proxy comparisons for surface temperature and monsoon circulation

模型-代理比较是气候变化科学的基石。本项目介绍了一种新的、定量的模式代理比较方法，用于快速发展的瞬态气候模拟新领域。该方法将模型-代理比较的适用性扩展到更广泛的研究社区和可用于与模型结果进行比较的代理记录的范围。具体来说，这项工作涉及布朗大学、威斯康星大学和中国科学院西安地球环境研究所的研究人员的合作努力。一个完全耦合的气候模式（社区气候系统模式第3版）；CCSM3)将使用加速日照强迫在时间依赖模式下运行，以模拟地球历史上两个关键时期的气候演变，即过去30万年（与温室气体、极地冰盖和海平面变化有关的高幅度气候变率时期）和3142万至284.2万年前（日照强迫相同但温室气体、冰盖和海平面变化幅度小得多的时间间隔）。这两个模式实验及其组成强迫将相互比较，以研究模式产生的气候对冰量和温室气体变化的敏感性，重点是热带表面温度和季风环流。该模式的结果还将与以前发表的来自海洋和陆地地质档案的地表温度和季风环流记录进行比较。这种比较将特别侧重于地表温度变化的时间（阶段）和相对于日照（轨道）、冰量和温室气体变化的季风环流。将模型中气候响应的阶段与代理记录进行比较的重点是利用了这样一个事实，即阶段是一个可靠的度量，可以通过广泛的代理进行量化。成功的模式-代理比较有助于验证模式的可靠性，并提高使用模式识别气候变化的潜在物理特性的信心。模型结果将广泛提供并存档于NOAA/NCDC世界数据中心。资助布朗大学的一名全日制研究生，该研究生将与中国科学院的一名全职博士后研究员密切合作（该项目不收取费用）。这种互动将确保学生在气候建模方面有深入的经验，博士后研究人员在地质代理生成和分析方面有深入的经验。促进这种密切的合作方式，包括高级研究人员的监督和科学领导，对于进一步促进这两个领域的研究人员的协同整合至关重要。

Model-proxy comparison is a cornerstone of climate change science. This project introduces a new, quantitative approach to model-proxy comparison for application to the new and rapidly developing field of transient climate modeling. The approach expands applicability of model-proxy comparisons to a broader research community and the range of proxy records that can be used in comparison with model results.Specifically, the work involves a collaborative effort between investigators at Brown University, the University of Wisconsin, and the Institute of Earth's Environment, Chinese Academy of Sciences (CAS), Xian. A fully-coupled climate model (Community Climate System Model-version 3; CCSM3) will be run in time-dependent mode using accelerated insolation forcing in order to simulate the evolution of climate during two key intervals in Earth history, the past 300,000 years (a time of high-amplitude climate variability related to changing greenhouse gases, polar ice sheets and sea level) and 3.142 to 2.842 million years ago (an interval of time with the same insolation forcing but much smaller amplitude changes in greenhouse gases, ice sheets, and sea level). These two model experiments and their component forcings will be compared to one another to study the sensitivity of the model-produced climate to changing ice volume and greenhouse gases with an emphasis on tropical surface temperatures and monsoonal circulation. The model results will also be compared to previously published records of surface temperature and monsoonal circulation from marine and terrestrial geological archives. This comparison will focus specifically on the timing (phase) of changes in surface temperature and monsoonal circulation relative to changes in insolation (orbital), ice volume and greenhouse gases. This focus on comparing the phase of the climate response in the model and proxy records leverages the fact that phase is a robust metric that can be quantified from a wide range of proxies. Successful model-proxy comparisons serve to validate model reliability and promote confidence in the use of models for identifying the underlying physics of climate change. Model results will be widely available and archived at the NOAA/NCDC World Data Center. Funding supports a full time graduate student at Brown University, who will work closely with a full time post-doctoral researcher at CAS (no cost to this project). This interaction will ensure an in-depth experience in climate modeling for the student and experience in geological proxy generation and analysis for the post-doctoral researcher. Fostering this close collaborative approach, including oversight and scientific leadership by the senior researchers, is crucial to furthering the synergistic integration of researchers from these two fields.