张少波,吕世华,赵勇,杨显玉. 2019. 基于风场季节变率的高原季风指数算法的改进及对比[J]. 气象学报, 77(2):315-326, doi:10.11676/qxxb2019.019
基于风场季节变率的高原季风指数算法的改进及对比
An improvement of the Plateau monsoon index based on seasonal variation of wind and its comparison with other indexes
投稿时间:2018-01-29  修订日期:2018-09-30
DOI:10.11676/qxxb2019.019
中文关键词:  高原季风指数  夏季降水  指数对比
英文关键词:Plateau monsoon index  Summer precipitation  Index comparison
基金项目:高原大气与环境四川省重点实验室开放课题(PAEKL-2018-Y2)、国家自然科学基金项目(41775016、41875102)、成都信息工程大学引进人才启动项目(KYTZ201737)。
作者单位
张少波 成都信息工程大学大气科学学院 高原大气与环境四川省重点实验室 气候与环境变化联合实验室, 成都, 610225 
吕世华 成都信息工程大学大气科学学院 高原大气与环境四川省重点实验室 气候与环境变化联合实验室, 成都, 610225
中国科学院西北生态环境资源研究院 寒旱区陆面过程与气候变化重点实验室, 兰州, 730000
南京信息工程大学 气象灾害预报预警与评估协同创新中心, 南京, 210044 
赵勇 成都信息工程大学大气科学学院 高原大气与环境四川省重点实验室 气候与环境变化联合实验室, 成都, 610225 
杨显玉 成都信息工程大学大气科学学院 高原大气与环境四川省重点实验室 气候与环境变化联合实验室, 成都, 610225 
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中文摘要:
      关于青藏高原季风,现有研究分别从近地层的热低压、气旋式环流切变以及风场的涡度和散度等角度定义了高原季风指数,但现有指数均更多地关注高原空间场的对比,而没有考虑风场的冬、夏转换特征。因此,在之前的工作中,基于风场季节变率指数,从高原近地层冬、夏风场对比的角度定义了一种新的高原季风指数,这里对该指数进行改进和简化,以便于其的进一步推广。为了验证改进的效果,使用ERA-interim再分析数据计算高原季风指数,并比较了不同高原季风指数年变化和年际变化的差异及其与夏季降水相关的差异。结果表明:(1)改进后的高原季风指数物理含义清楚,弥补了原指数计算复杂的不足。(2)物理基础的差异使得新指数在8月达到峰值,不同于其他指数在6月达到峰值。整体而言,不同高原季风指数和高原降水的年变化特征均有较高的一致性。(3)新指数能够较好地表征高原季风与高原夏季降水东、西反相的相关系数分布特征,且不同于其他指数在高原一致的相关系数分布特征,对于高原地区降水,尤其是高原东南部人口相对密集地区的降水预测具有较好的指示意义。
英文摘要:
      When considering the Tibetan Plateau (TP) monsoon, different TP monsoon indexes have been defined from various perspectives, such as the near surface layer thermal low, the cyclonic circulation shear, the vorticity and divergence of wind field, etc. However, these existing indexes are more concerned of the spatial contrast of the variable and have not considered the characteristics of wind field change between the summer and winter. To address this issue, a new TP monsoon index has been proposed based on seasonal variation of winds in the author's previous work. The new index is further improved and simplified in the present paper. The ERA-interim reanalysis data is used to calculate six different TP monsoon indexes. Annual and inter-annual variations of the six indexes and their correlation coefficients with summer precipitation are compared. The results show that the algorithm for the calculation of the new TP monsoon index is simple but with clear physical meaning. Due to differences in the physics considered, the new TP monsoon index peaks in August, which is different to other indexes that peak in June. In general, characteristics of annual variations of different monsoon indexes and precipitation agree well with each other. The correlation coefficient between the new TP monsoon index and summer precipitation shows opposite signs between the western and eastern TP, while a consistent positive correlation coefficient distribution can be found on the TP between other TP monsoon indexes and summer precipitation. Above all, the new TP monsoon index shows a satisfactory result especially in the southeastern part of TP, which is a relatively densely populated area. Thereby, this new index has potential application value in the summer precipitation prediction over the TP.
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