Mesoscale Modeling of Tropical Paleoclimate

热带古气候的中尺度模拟

• 批准号: 0123797
• 负责人: Kerry Cook
• 金额: $ 26.06万
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0123797&HistoricalAwards=false
• 关键词: Mesoscale; Modeling; Tropical; Paleoclimate

This award will serve to develop and apply a mesoscale modeling system for studying past variability in tropical climates of Africa and South America during the Last Glacial Maximum (LGM). The modeling system consists of two models. A mesoscale climate model (MCM) will simulate climate on space scales of tens of kilometers. A general circulation model (GCM) will generate lateral boundary conditions on wind, temperature, and moisture for the mesoscale model. Simulations of the dry climates of the present day and LGM (~21,000 years ago) over northern Africa will be contrasted with simulations for the African Humid Period, approximately 6,000 years ago when Sahelian and Saharan Africa supported numerous lakes and extensive vegetation. The research will address the following questions:-What are the individual and combined roles of insolation, changes in land surface conditions, regional SST differences, and differences in large-scale climate (i.e., MCM lateral boundary conditions) in causing differences in surface wetness over northern Africa among the present day, African Humid Period and the LGM?-Are the differences in wetness associated with changes in precipitation only, or do changes in evaporation and/or water table levels play an important role?-What mechanisms are involved in changing the atmospheric column water vapor budget? -Are any important mechanisms nonlinear in a way that helps explain the speed with which the climate can change in this region? What are the implications for future climate change (global warming)?Simulations with various combinations of lateral and surface boundary conditions, as well as other forcing functions such as insolation and atmospheric composition, will identify the important factors and physical mechanisms that lead to the wet conditions and the rapid climate change that is hypothesized to have occurred in Amazonia during the Holocene. The mesoscale modeling system will also be used to study South American climate of the LGM.The research will address the following questions:-What was the distribution of drying and cooling during the LGM in the Amazon Basin and what mechanisms are associated with the differences from the present day climate?-What differences in aridity in the Central Andes are simulated with the MCM, and what mechanisms account for differences from the present day?-How are the simulated differences in both regions related to global-scale climate conditions and how are they linked?-Does the model support the idea that there are different aridity trends in different areas of the high Central Andes? If so, are these trends providing information about inter-hemispheric symmetry or asymmetry of climate change during the last glacial cycle?

该奖项将有助于开发和应用一个中尺度建模系统，以研究在最后一次冰川最大值（LGM）期间非洲和南美热带气候中的过去变异性。建模系统由两个模型组成。中尺度气候模型（MCM）将在数十公里的空间尺度上模拟气候。通用循环模型（GCM）将在中尺度模型上生成风，温度和水分的横向边界条件。 北非北非的LGM和LGM（约21，000年前）的干燥气候的模拟将与非洲潮湿时期的模拟形成对比，大约在6000年前，萨赫勒利安和撒哈拉以来的非洲非洲支持了许多湖泊和广泛的植被。这项研究将解决以下问题： - - 潜水的个体和综合作用，土地表面条件的变化，区域SST差异以及大规模气候的差异（即MCM横向边界条件）在导致北非北部非洲的表面湿度差异在当今的北部地区的表面湿度差异，与当今的非洲湿度和湿度的差异相关，或者与LGM的差异相关，或者在湿度上差异或与湿度的变化相关。一个重要的角色？ - 改变大气色谱柱水蒸气预算中涉及哪些机制？ - 是否有任何重要的机制非线性，有助于解释气候可以改变该地区的速度？对未来气候变化（全球变暖）的影响是什么？具有各种横向边界条件和表面边界条件组合的模拟以及其他强迫功能（例如，破坏和大气组成）将确定导致潮湿条件的重要因素和物理机制，这些因素和物理机制会导致潮湿的条件以及在整个整个整个整个整个过程中都发生的快速气候变化。中尺度的建模系统还将用于研究LGM的南美气候。研究将解决以下问题： - 亚马逊盆地LGM期间的干燥和冷却的分布是什么，以及与当今气候的差异有关的机制与MCM的差异以及与当天的差异相关的不同机械差异与参与者的差异有关？与全球尺度的气候条件有关，它们如何联系？如果是这样，这些趋势是否提供有关最后一个冰川周期中气候变化的半球间对称性或不对称的信息？