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: 0909194
• 负责人: John Eiler
• 金额: $ 18.66万
• 依托单位: California Institute of Technology
• 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 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909194&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，青藏高原一直被认为是扰动大气环流的最大地形特征，它是了解形成高地的地球动力学过程的理想野外实验室。因此，青藏高原的生长应该有大气环流。尽管最近有许多研究，我们仍然不知道青藏高原何时达到目前的规模以及它如何扰动大气。该项目将地球动力学家、大气科学家和古气候学家联合起来，对发生的时间和方式进行多学科研究。该项目的主要目标之一是量化西藏因逆冲断层和褶皱而增厚的程度。 ，通过地壳内的流动重新分配那里的物质，或者通过用较热的物质替换冷的地幔岩石圈（所有这些都处于均衡状态），这样的量化将在了解有多高方面迈出一大步。高原的形成以及大陆岩石圈如何变形，是地球动力学前沿的主题，需要确定地壳缩短和增厚的发生时间，使用基本的现场方法和现代实验室技术，并使用新的同位素工具量化古海拔。然而，古测高技术不仅需要了解大气如何输送同位素，还需要了解不断变化的高地地形如何影响过去的地表温度。该项目的重点仅在于西藏的发展，该研究的气象部分，尤其是东亚的水文循环，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。在未来气候的未知因素中，水文循环尤为突出。因此，重点将放在了解西藏等高地如何影响东亚，特别是中国的水文循环。高原如何地形障碍和太阳辐射汇影响大气环流；(2) 大气如何输送稳定同位素（ä18O 和 äD）；(3) 它如何影响中纬度气候变化，包括如何通过背风气旋发生作用飘浮和运输灰尘，以及（4）植被如何反馈大气环流和水文循环作为多米尔时间尺度发生的地质过程与人类时间尺度发生的地质过程的联系，主要研究人员计划。利用黄土沉积和量化古气候的洞穴沉积物专门研究过去数十万年的古降水情况。