AGS-PRF: Indo-Pacific Hydrology in a Warming World: Modeled and Observed Responses to Climate Forcings from the Little Ice Age to Present

在21世纪世纪气候变化情景下，全球降雨模式的未来是高度不确定的，部分原因是热带印度洋-太平洋气候模式（例如，厄尔尼诺-南方涛动）对温室气体强迫作出反应。气候模型预测全球水文循环会因温室气体强迫而发生重大变化，但降水量的仪器记录很短，无法对潜在的人为趋势进行可靠的评估。古气候代用数据和模型模拟有助于阐明印度-太平洋地区对温室气体和近期地质历史中其他气候强迫的反应，从而有助于这一奋进。在过去的500年里，太阳辐照度、火山活动和大气温室气体的变化使全球气候走出了“小冰河时代”（LIA; 1450-1750 C.E.）。进入了气候变暖的现代。水文气候代用记录，许多是基于降水、地表沃茨和海水中的氧和氢同位素，记录了从LIA到现在的巨大的印度洋-太平洋水文变化。虽然对这些异常的原因知之甚少，但“同位素装备”气候建模和古气候数据合成的新发展提供了新的，有前途的工具，通过直接比较古气候数据与模型输出来理解这些变化。博士后研究员将调查印度的反应，用综合古气候模拟和数据综合框架研究过去500年太平洋水文循环对气候强迫的影响。上个千年（850-2000 C.E.）的现有“单一强迫”模拟气候与完全耦合的共同体地球系统模型将用于强制新的模拟与同位素装备的大气模型，使火山，太阳和温室气体引起的变化的特征，在印度-太平洋水文循环和相关的水同位素签名自1500年C.E.与此同时，将对过去500年的水文和水同位素替代数据进行综合，以分离出自LIA以来印度-太平洋地区稳健的水文和同位素模式。新出现的“最佳做法”古气候数据综合和模型比较技术将用于确定印度洋-太平洋水文循环对单独和综合气候强迫的反应。结果将促进我们对自然和人为气候变化如何影响热带水文循环的理解-这是未来预测中不确定性的关键来源

The future of global rainfall patterns under 21st century climate change scenarios is highly uncertain, due in part to major uncertainties in how tropical Indo-Pacific climate modes (e.g., the El Niño-Southern Oscillation) respond to greenhouse gas (GHG) forcing. Climate models project significant changes in the global hydrological cycle in response to GHG forcing, yet the short instrumental record of precipitation precludes a robust assessment of potential anthropogenic trends. Paleoclimate proxy data and model simulations can be useful in this endeavor by helping to illuminate the Indo-Pacific response to GHGs and other climate forcings in the recent geologic past. During the past 500 years, a combination of changes in solar irradiance, volcanism, and atmospheric GHGs drove global climate out of the "Little Ice Age" (LIA; 1450-1750 C.E.) and into the modern era of warming. Hydroclimate proxy records, many based on oxygen and hydrogen isotopes in precipitation, surface waters, and seawater, document enormous Indo-Pacific hydrological changes from the LIA to present. While the causes of these anomalies are poorly understood, new developments in both "isotope-equipped" climate modeling and paleoclimate data synthesis provide new, promising tools for understanding these changes by directly comparing paleoclimate data with model output.In this project, the postdoctoral research fellow will investigate the response of the Indo-Pacific hydrological cycle to climate forcings during the past 500 years using an integrated paleoclimate modeling and data synthesis framework. Existing "single-forcing" simulations of Last Millennium (850-2000 C.E.) climate with the fully-coupled Community Earth System Model will be used to force new simulations with an isotope-equipped atmospheric model, enabling a characterization of volcanic, solar, and GHG-induced changes in the Indo-Pacific hydrological cycle and associated water isotopic signatures since 1500 C.E. Simultaneously, a synthesis of hydrologic and water isotopic proxy data from the past 500 years will be performed to isolate robust hydrologic and isotopic patterns in the Indo-Pacific since the LIA. Emerging "best-practice" techniques for paleoclimate data synthesis and model comparison will be used to characterize the response of the Indo-Pacific hydrological cycle to individual and combined climate forcings. Results will advance our understanding of how natural and anthropogenic climate change impact the tropical hydrological cycle -- a key source of uncertainty in future projections