Late-Pliocene Ice-Age Initiation

关键古气候指标（底栖有孔虫）的周期性或准周期性变化。18O和。13C， %CaCO3和浮游有孔虫种群)发生在大约3至2.47 Myr之间。利用数据分析和环流模型的敏感性实验，该项目将探索这些振荡是否是由北半球相对较小的冰盖的变化驱动的，这些冰盖没有将冰山崩解到开阔的大西洋，还是由北极海冰极限的大规模变化驱动的。在北半球冰河时代的许多可能原因中，该项目将探索东南亚（西藏、喜马拉雅山）和美国西南部（科罗拉多高原、落基山脉）大规模构造隆起对北半球行星波的影响（从而对地球表面气候的影响）。新的分析将扩展高分辨率的同位素时间序列，用一个包括相互作用的混合层海洋的模型进行的实验将更准确地定义晚新生代构造隆起的全部气候影响。这个项目将研究“更新世”冰期开始前的气候波动，以及冰期本身的开始（实际上开始于320万年前，大约比更新世开始早100万年）。该项目将利用气候相互作用的计算机模型来研究气候和海洋环境与主要高海拔陆地块的构造隆起之间的反馈机制。这将是第一次尝试对如此多的变量进行建模，这些变量是对导致冰河时代开始的气候变化作出反应的原因。

Periodic or quasi-periodic variations in key paleoclimatic indicators (benthic foraminiferal .18O and .13C, %CaCO3, and planktonic foraminiferal populations) occurred between roughly 3 and 2.47 Myr. Using data analyses and sensitivity experiments with General Circulation Models, this project will explore whether these oscillations were driven by variations in relatively small Northern Hemisphere ice sheets that did not calve icebergs to the open Atlantic ocean or by large-scale changes in Arctic sea-ice limits. Among many possible causes of the Northern Hemisphere ice age, the project will explore the effect of large-scale tectonic uplift in Southeast Asia (Tibet, Himalayas) and the American southwest (Colorado Plateau, Rockies) on the Northern Hemisphere planetary waves (and thus on climate at the earth's surface). New analyses will extend the high-resolution isotopic time series, and experiments with a model including an interactive mixed-layer ocean will define more accurately the full climatic effects of Late-Cenozoic tectonic uplift. %%% This project will examine climatic fluctuations preceding the initiation of the "Pleistocene" ice ages and the initiation of the ice age itself (which actually began 3.2 million years ago; approximately 1.0 million years before the Pleistocene began). The project will utilize computer models of climate interactions in order to examine the feed-back mechanisms of climate and ocean environments with the tectonic uplifts of major high-altitude land masses. This will be the first attempt to model so many of the variables the cause of respond to climate changes that resulted in the initiation of the ice ages.