兰州大学机构库 >大气科学学院
中国西南地区夏季降水年际变化及其与大气水汽收支的关系
Alternative TitleAtmospheric moisture budget and its regulation of the summer precipitation variability over the Southwestern China
曲姝霖
Thesis Advisor张文煜
2018-05-04
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name学士
Keyword中国西南地区夏季降水 大气水汽收支平衡 动力学变量 西太副高
Abstract

本文主要利用欧洲中期天气预报中心(ECMWF)提供的全球再分析资料,对中国西南地区1979~2016年夏季(6 ~ 8月)降水的年际变化特征进行探究,并进一步利用水汽收支方程分析了各项对降水量的贡献。结果表明:中国西南地区夏季降水量空间呈现东南向西北递减分布,并且年际变率也呈类似分布。此外,夏季降水量还存在明显的年际变化特征,主要周期为2-4和4-6年。西南地区夏季降水量的变化主要是由于大气环流异常引起的水汽输送项异常导致,而这主要是风速异常引起的动力散度项的贡献,其次是由于蒸发量的贡献。此外,西太平洋副热带高压(以下简称西太副高)及其脊线与水汽输送密切相关,当西太副高脊线位置异常偏东时,风场辐散,水汽减弱,西南地区的降水减小;当西太副高脊线位置异常偏西时,风场辐合,水汽增强,从而使西南地区降水量增加。近年来西太副高西伸极点位置的不同变化可能是造成西南地区降水异常的主要原因之一。

Other Abstract

The interannual variability of the summer (June–July–August) precipitation and atmospheric moisture budget over the Southwastern China were examined during 1979–2016 using the global monthly average reanalysis data provided by the European Medium-Term Weather Forecasting Center (ECMWF).

The analysis shows that the summer precipitation in southwestern China shows a decreasing distribution from southeast to northwest, and the interannual variability is also similar. The periodicity of summer precipitation in the southwest region is mainly 2-4 years and 4-6 years. The study of summer moisture budget in Southwestern China shows that the main component of precipitation variability is the moisture transport caused by the atmospheric circulation anomaly. This is mainly due to the contribution of the dynamic divergence caused by wind speed anomalies. Second, due to the contribution of evaporation. Among many summertime circulation systems, the western Pacific subtropical high and its western ridge are closely related to moisture transport and thus summer precipitation over the southwestern China. The changes in the position of the southwest ridge line affects the moisture convergence divergence situation so as to influence the summer precipitation in southwestern China. In recent years, abnormal changes of ridges may be the major causes of precipitation anomalies in southwestern China.

URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/200168
Collection大气科学学院
Recommended Citation
GB/T 7714
曲姝霖. 中国西南地区夏季降水年际变化及其与大气水汽收支的关系[D]. 兰州. 兰州大学,2018.
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