张硕,姚秀萍. 2019. 基于客观判识的青藏高原横切变线结构及演变特征合成研究[J]. 气象学报, ():-, doi:10.11676/qxxb2019.058
基于客观判识的青藏高原横切变线结构及演变特征合成研究
Synthesis study of the structure and evolution characteristics of the transversal line of Tibetan Plateau based on objective identification
投稿时间:2018-09-17  修订日期:2019-04-28
DOI:10.11676/qxxb2019.058
中文关键词:  高原横切变线,合成,结构,演变,特征,客观判识
英文关键词:the meridionally-oriented shear lines over the Tibetan Plateau, synthesis, structure, evolution, characteristics, objective identification
基金项目:国家自然科学基金项目(91637105、41775048和41475041)、国家重点研发计划重点专项项目(2018YFC1507804)
作者单位E-mail
张硕 1. 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 2. 中国气象局气象干部培训学院 2692416989@qq.com 
姚秀萍 中国气象局气象干部培训学院 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 yaoxp@cma.gov.cn 
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中文摘要:
      [资料与方法]利用1981—2016年6—8月每日4次,分辨率为1°×1°的ERA-Interim再分析资料,基于纬向风的经向切变、纬向风速零线和相对涡度三个参数,在计算机客观自动判识青藏高原横切变线(以下简称高原横切变线)基础上,选取了位于33°-35°N之间的高原横切变线个例13个,采用合成分析技术,[目的]研究了青藏高原横切变线结构及演变特征。[结果和结论]表明:高原横切变线位于高原主体80°—100°E范围内,在500hPa 高度上呈准水平分布的东西走向、水平尺度可达2000km,垂直方向在高原上空可伸展至480hPa高度上、厚度可达近2km。高原横切变线出现的环流背景是,500hPa高纬度两槽两脊,青藏高原两侧分别为带状分布的西太平洋副热带高压(以下简称西太副高)和伊朗高压。在动力场上,高原横切变线走向与500hPa正涡度带轴线走向一致,切变线附近为带状的涡度正值区和上升运动区,对应于无辐散带,辐散/辐合带分布在高原横切变线北/南侧;高原横切变线附近正涡度带垂直可伸展到350hPa,上升运动伸展至200hPa,但高原切变线仅到480hPa左右,为浅薄的斜压性天气系统,呈现随高度向北倾的特征。在水汽热力场上,高原横切变线是水汽汇聚带;高原横切变线附近南侧的600-500hPa之间存在高假相当位温中心,具有非常明显的高温高湿的特征。高原横切变线从初始产生到发展强盛再减弱的演变发展过程中,其生命史近4天,伴随西太副高西移过程,随着高原横切变线附近正涡度带范围增大、强度增强,高原横切变线发展,干冷空气的侵入导致高原横切变线强度减弱甚至消亡。
英文摘要:
      Using the ERA-Interim reanalysis dataset of 4 times a day in June—August 1981—2016 with a resolution of 1 °× 1 °, based on three parameters which are the meridional shear of zonal wind, the zero line of zonal wind speed and the relative vorticity, and the automatic identification of the meridionally-oriented shear lines over the Tibetan Plateau(MOSLs), a total of 13 cases of MOSLs between 33-35 °N were selected. Using synthetic analysis technique, the structure and evolution characteristics of MOSL are studied. The results show that: MOSL is located in the plateau of the cross subject within the scope of 80°—100°E, presenting a east-west trend with a quasi-horizontal distribution at the height of 500hPa, and the horizontal dimension can reach 2000km. The vertical direction of MOSL over the plateau can be extended to 480hPa, whose thickness can up to near 2km. The circulation background of MOSL is the circulation situation of the two-trough and two-ridge of high latitude in 500hPa, the western Pacific subtropical high (hereinafter referred to as WPSH) and the Iran high are distributed on both sides of the Qinghai-Xizang Plateau respectively. On the dynamic filed, MOSL is consistent with the axis of the 500hPa positive vorticity zone, there are zonal vertical vorticity positive regions and ascending motion regions near MOSL, corresponding to the non-divergence zone, the divergence convergence zone distributes on the north / south side of MOSL; The positive vorticity zone near MOSL can extend vertically to 350 hPa, and the ascending motion extends to 200hPa, but the shear line only extends to about 480hPa, which is a shallow weather system with a certain baroclinic property and a northward inclination with height. On the water vapor thermal field, MOSL is the water vapor convergrnce zone, and there is a high pseudo-equivalent temperature center between the 600-500hPa in the southern side of MSOL, it has very obvious characteristics of high temperature and high humidity. In the evolution process of MOSL from initial generation to strong development and then weakening, its life history is nearly 4 days, along with the westward shift of WPSH. With the range and the intensity of positive vorticity zone near MOSL increases, MOSL develops. With the invasion of dry cold air, the intensity of MOSL decreases or even dies.
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