Collaborative Research: Growth of the Tibetan Plateau and Eastern Asia Climate: Clues to Understanding the Hydrological Cycle

合作研究：青藏高原的增长和东亚气候：了解水文循环的线索

• 批准号: 0908711
• 负责人: Marin Clark
• 金额: $ 32.26万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908711&HistoricalAwards=false
• 关键词: Collaborative; Research; Growth; Tibetan; Plateau

For fifty years, the Tibetan Plateau has been recognized as the largest topographic feature that perturbs atmospheric circulation. It serves as an ideal field laboratory for understanding the geodynamic processes that build high terrain. Accordingly, the growth of the plateau should have altered atmospheric circulation and therefore written an evolving paleoclimatic signature not only on eastern Asian regional climates, but on global climate as well. Despite many recent studies, we still do not know precisely when the Tibetan Plateau reached its current dimensions and how it perturbs atmospheric circulation. This project brings together geodynamicists, atmospheric scientists, and paleoclimatologists in a multidisciplinary study of the when and the how.One of the major goals of the project is to quantify the extent to which Tibet has grown by crustal thickening, by thrust faulting and folding, by flow within the crust that redistributes material there, or by replacement of cold mantle lithosphere with hotter material (all in a state of isostatic equilibrium). Such quantification will take big steps toward the understanding of how high plateaus are built and how continental lithosphere deforms, topics at the forefront of geodynamics. Determining how Tibet has grown will require determining when crustal shortening and thickening occurred, using basic field methods and modern laboratory techniques, and quantifying paleoaltitudes with new isotopic tools. Applying such paleoaltimetric techniques, however, requires an understanding not only of how the atmosphere transports isotopes, but how the evolving high terrain affected surface temperatures at times in the past. Even if the project?s focus were solely on how Tibet has grown, a meteorological component of the study, focused particularly on eastern Asia?s hydrological cycle, would be necessary. Most continental paleoclimatic indicators are thought to be more sensitive to precipitation than to temperature, and among the unknowns of future climate, the hydrological cycle stands out. Accordingly, a major focus will be on understanding how high terrain like Tibet affects the hydrological cycle of eastern Asia, and China in particular. These studies will focus on: (1) how the plateau, as both a topographic obstacle and a sink for solar radiation, affects atmospheric circulation; (2) how the atmosphere transports stable isotopes (ä18O and äD); (3) how it affects mid-latitude climate variability, including how, via lee cyclogenesis, it lofts and transports dust, and (4) how vegetation feeds back on atmospheric circulation and the hydrological cycle. As links from geologic processes occurring at multi-Myr time scales to those on human time scales, the Principal Investigators plan studies that specifically examine paleoprecipitation over the past few hundred thousand years, using both loess deposition and speleothems that quantify paleoclimate.

五十年来，藏族高原一直被认为是大气圈的最大地形特征。它是理解理想的现场实验室，用于理解建立高地形的地球动力学过程。彼此之间，高原的增长应该改变大气环，因此不仅在东亚地区气候下，而且在全球气候下写了一个不断发展的古气候签名。尽管最近进行了许多研究，但我们仍然不确定何时藏族高原达到其当前尺寸以及它如何消除大气循环。该项目将何时及以后的多学科研究汇集了地球动力学家，大气质科学家和古气候学家。平衡）。这种量化将迈出重要的一步，以了解高原的建筑高度以及岩石圈的连续变形，主题是地球动力学的最前沿。确定西藏的生长将如何使用基本的现场方法和现代实验室技术确定何时发生地壳缩短和增厚，并使用新的同位素工具来量化古质量。但是，应用这种古占学技术不仅需要了解大气如何运输同位素，而且还需要了解过去如何影响高地形的表面温度。即使该项目的重点仅仅是西藏如何成长，这是研究的气象成分，特别集中在东亚的氢循环上，也是必要的。大多数大陆古气候指标被认为对降水比对温度更敏感，在未来气候的未知数中，液压循环脱颖而出。据认为，主要重点是了解像西藏这样的高地形如何影响东亚，尤其是中国的水文循环。这些研究将重点介绍：（1）高原如何作为太阳辐射的地形障碍物和水槽如何影响大气循环； （2）大气如何运输稳定的同位素（ä18o和äd）； （3）它如何影响中纬度气候变异性，包括如何通过Lee Cycerenesis，它抬高和运输灰尘，以及（4）植被如何以大气环流和水文循环为基础。随着地质过程的联系在多人时间尺度上与人类时间尺度上的链接，主要研究人员计划研究，该研究使用量化古气候的黄土沉积物和棘突味，在过去几十万年内专门检查古征沉淀。