年代际时间尺度北大西洋海-气相互作用对夏季降水“西风模态”的影响

项目名称： 年代际时间尺度北大西洋海-气相互作用对夏季降水“西风模态”的影响

项目编号： No.41505043

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 黄伟

作者单位： 兰州大学

项目金额： 21万元

中文摘要： 全新世轨道-千年-百年-年代际尺度上中纬度亚洲内陆干旱区的湿度（降水）变化与东亚季风区呈现出错/反位相的变化，称为中纬度亚洲气候变化的“西风模态”。不仅如此，在年代际尺度上中纬度亚洲内陆干旱区部分区域的夏季降水与其东部的东亚季风区和西部的地中海周边地区均呈现出相反变化的空间格局。环球遥相关（CGT）可以部分解释年代际尺度“西风模态”的形成机制，而低纬地区加热是产生CGT，从而间接影响亚洲内陆干旱区降水变化的一个因素。北大西洋海（AMO）-气（NAO）之间的相互作用对北半球的气候变化有重要的影响，有可能是影响“西风模态”的另一个重要因素。本项目将以现代降水数据集和过去数百年欧亚大陆高分辨率湿度（降水）代用资料为基础，结合再分析数据集，深入分析和探讨夏季年代际尺度北大西洋海-气作用对“西风模态”影响的动力过程，并利用CMIP5计划中可靠性好的模式来验证该物理机制并预测未来“西风模态”的变化。

中文关键词： 年代际变化；“西风模态”；海气相互作用；大气遥相关；物理机制

英文摘要： The term “westerlies-dominated climatic regime” describes the pattern of precipitation/moisture variations between westerlies-dominated arid Central Asia (ACA) and mid-latitude monsoon-dominated Asia on decadal to multi-millennial time scales. Further results suggest the existence of an opposing variations of summer precipitation between ACA and monsoon-dominated East Asia and Mediterranean on decadal time scales. The warmer (cooler) SST in the northern Indian Ocean and associated reduced (excess) precipitation (a proxy of heating) in northern Indian Ocean and Indian subcontinent, may lead to weaker (stronger) circumglobal teleconnection (CGT), which have an important effect on the wetter (drier) ACA. However, as another important impact factor, air (North Atlantic Oscillation, NAO)-sea (Atlantic Multidecadal Oscillation, AMO) interaction may cause the precipitation variations similar to the “westerlies-dominated climatic regime”. In this study, we will first analyze the possible impact of air-sea interaction on summer “westerlies-dominated climatic regime” on decadal time scales using the global monthly precipitation dataset and the moisture (precipitation) proxy data during the centuries over mid-latitude Eurasia. Then the reanalysis datasets (e.g., NCEP-CFSR, ERA et al.) were analyzed to investigate the physical processes facilitating the AMO and NAO impacts. Finally, we will evaluate the simulations from the Coupled Model Inter-comparison Project (CMIP5) to identify the models that can simulate the possible physical mechanisms and evaluate the precipitation characteristics of “westerlies-dominated climatic regime” in future.

英文关键词： Decadal variations;Westerlies-dominated climatic regime;Air-sea interaction;Atmospheric teleconnection Pattern;Physical mechanisms