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

模型-替代物比较是气候变化科学的基石。 该项目介绍了一种新的，定量的方法，模式代理比较应用于新的和迅速发展的领域瞬态气候模拟。 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，并扩展了可用于与模型结果进行比较的代理记录范围。具体而言，这项工作涉及布朗大学、威斯康星州大学和中国科学院西安地球环境研究所的研究人员之间的合作努力。 一个完全耦合的气候模式（社区气候系统模式-第三版; CCSM 3）将以时间依赖模式运行，使用加速的太阳辐射强迫，以模拟地球历史上两个关键时期（过去30万年）的气候演变（一个与温室气体变化有关的气候变化幅度很大的时期，极地冰盖和海平面）和314.2至284.2万年前（具有相同的日照强迫但温室气体、冰盖和海平面变化幅度小得多的时间间隔）。 这两个模型实验及其分量强迫将相互比较，以研究模型产生的气候对变化的冰量和温室气体的敏感性，重点是热带表面温度和季风环流。 模型结果还将与先前公布的海洋和陆地地质档案中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和季风环流相对于日射（轨道）、冰量和温室气体变化的时间（阶段）变化。 这种侧重于比较模型和代理记录中气候响应的阶段的做法利用了这样一个事实，即阶段是一个强大的度量标准，可以从广泛的代理中量化。 成功的模型-代用品比较有助于验证模型的可靠性，提高对使用模型查明气候变化基本物理现象的信心。 模型结果将广泛提供，并在海洋大气署/国家海洋和大气数据中心世界数据中心存档。资金支持布朗大学的一名全职研究生，他将与中科院的一名全职博士后研究员密切合作（本项目无费用）。这种互动将确保学生在气候建模方面的深入经验，以及博士后研究人员在地质代理生成和分析方面的经验。 促进这种密切合作的方法，包括高级研究人员的监督和科学领导，对于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.