| 我国春夏季地气温差的时空变化特征及其与夏季降水的联系 |
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| 引用本文： | 周连童,温李明.我国春夏季地气温差的时空变化特征及其与夏季降水的联系[J].气候与环境研究,2016,21(6):621-632. |
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| 作者姓名： | 周连童 温李明 |
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| 作者单位： | 中国科学院大气物理研究所季风系统研究中心, 北京 100190,成都市气象局, 成都 610072 |
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| 基金项目： | 国家自然科学基金项目41175055、41475053,国家重点研发计划2016YFA0600603 |
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| 摘 要： | 利用1960~2006年我国地温、气温逐日4个时次02:00(北京时间,下同)、08:00、14:00和20:00]的和中国降水台站观测资料以及NCEP/NCAR再分析资料,分析了我国春季(3~5月)和夏季(6~8月)地气温差的时空变化特征及其与夏季降水的联系。分析结果表明:我国春季地气温差主要存在着3种空间模态分布,第1模态表现出我国西部地区地气温差为正值,我国东部地区从南至北呈现出"-、+、-、+"空间分布特征;而第2模态则呈现"+、-、+"的空间分布特征;第3模态则表现出一致的空间分布特征。我国夏季地气温差同样存在着3种空间模态分布,第1模态表现出我国东部和西部地区夏季地气温差反相的空间分布特征;第2模态则呈现出"-、+、-"的空间分布特征;而第3模态则表现出"+、-、+、-"的空间分布特征。分析结果进一步表明我国春季和夏季地气温差第1模态与我国长江中下游地区夏季降水均存在正相关关系,而与华北地区出现负相关关系。而且,夏季更加显著。这主要是由于我国东部和西部热力差异增强,有利于在我国东部地区出现西北风异常,这说明东亚夏季风偏弱,不利于水汽向北输送,有利于华北地区降水偏少。并且,在我国东南部地区出现水汽辐合和上升运动,从而有利于我国长江中下游地区夏季降水偏多。
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| 关 键 词： | 地气温差 时空变化特征 夏季降水 |
| 收稿时间： | 2015/8/24 0:00:00 |
Characteristics of Temporal and Spatial Variations in Land-Air Temperature Difference in China and Its Association with Summer Rainfall |
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| ZHOU Liantong and WEN Liming.Characteristics of Temporal and Spatial Variations in Land-Air Temperature Difference in China and Its Association with Summer Rainfall[J].Climatic and Environmental Research,2016,21(6):621-632. |
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| Authors: | ZHOU Liantong and WEN Liming |
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| Institution: | Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190 and Chengdu Meteorological Bureau, Chengdu 610072 |
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| Abstract: | Based on daily observations and NCEP/NCAR reanalysis data from 1960 to 2006, the characteristics of temporal and spatial variations in land-air temperature difference are analyzed by using EOF (Empirical Orthogonal Function) analysis. The results show that there are three principal spatial patterns of spring land-air temperature difference in China. The most dominant pattern shows a spatial distribution of "-" "+" "-" "+" from south to north in the spring land-air temperature difference. The second pattern shows spatial distribution of "+" "-" "+". The third pattern shows a spatially uniform distribution. There are also three principal spatial patterns of the summer land-air temperature difference in China. The most dominant pattern shows opposite spatial distributions of land-air temperature difference in eastern and western China. The second pattern shows a spatial distribution of "-" "+" "-". The third pattern shows a spatial distribution of "+" "-" "+".The analysis identifies a significant positive correlation between the land-air temperature difference and the summer rainfall in the middle and lower reaches of the Yangtze River, and a negative correlation over North China that more significant in the summer. The analysis results suggest that with increased thermal contrast between eastern and western China, northwesterly wind anomalies become more significant in eastern China. This will result in weaker than normal summer monsoon and is unfavorable for northward moisture transport. Moreover, under this circulation pattern, ascending motions and moisture convergence are located at southeastern China, which contribute to an increase in summer rainfall over the middle and lower reaches of the Yangtze River. |
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| Keywords: | Land-air temperature difference Temporal and spatial variation Summer rainfall |
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