干旱气象 ›› 2020, Vol. 38 ›› Issue (2): 195-204.DOI: 10.11755/j.issn.1006-7639(2020)-02-0195

• 论文 • 上一篇    下一篇

夏季金塔绿洲效应的理想数值试验研究

吴稀稀1,黄倩1,王婵2,田红瑛1,邱继勇1,张蕴帅1,刘宏超1   

  1. 1.兰州大学大气科学学院,甘肃 兰州 730000;
    2.中国科学院寒区旱区环境与工程研究所,甘肃 兰州 730000
  • 出版日期:2020-04-28 发布日期:2020-04-28
  • 通讯作者: 黄倩(1970— ),女,甘肃兰州人,博士,教授,主要从事大气边界层湍流及大涡模拟研究. E-mail: qianhuang@lzu.edu.cn。
  • 作者简介:吴稀稀(1992— ),女,河南商丘人,硕士研究生,主要从事大气边界层与陆气相互作用研究. E-mail: wuxx16@lzu.edu.cn。
  • 基金资助:
    国家自然科学基金项目(41775013,41875046)共同资助

Idealized Numerical Tests of Oasis Effect in Jinta Oasis in Summer

WU Xixi1, HUANG Qian1, WANG Chan2, TIAN Hongying1,QIU Jiyong1, ZHANG Yunshuai1, LIU Hongchao1   

  1. 1. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;
    2. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Online:2020-04-28 Published:2020-04-28

摘要: 利用复杂地形下高分辨率边界层数值模式BLASIUS,基于“绿洲系统非均匀下垫面能量水分交换和边界层过程观测与理论研究”实验期间的观测资料,通过一系列的理想数值试验,探讨了沙漠与绿洲间地表温差、浮力频率以及背景风速对绿洲效应的影响。结果表明:绿洲与沙漠间地表温差的增大对金塔绿洲上空“冷岛效应”和“湿岛效应”的增强作用主要表现在500 m高度以下,使得“冷岛”的宽度增加,“湿岛”的高度降低,且对“湿岛效应”的影响较“冷岛效应”滞后约1 h;增大浮力频率,绿洲上空的上升气流增多,1.5 km高度以上沙漠与绿洲过渡带的垂直速度增大;增大背景风速,绿洲与沙漠间的垂直环流的对称性减弱,环流中心的高度降低、强度减弱。

关键词: 绿洲效应, BLASUIS模式, 初始地表温差, 浮力频率, 背景风

Abstract: Based on the observation data during the period of the experiment with ‘theoretical study and observations of water and energy exchange and planetary boundary layer on inhomogeneous underlying surface in oasis system’, the influences of surface temperature difference between desert and oasis, buoyancy frequency (Brunt-Visl frequency) and background wind velocity on oasis effect were discussed by a series of idealized numerical tests of BLASIUS (boundary layer above stationary, inhomogeneous uneven surface) model with high resolution and complex terrain. The results show that the cold island effect and humid island effect enhanced with the increase of surface temperature difference between oasis and desert, and the enhancing action mainly occurred below 500 m over the ground. The horizontal range of ‘cold island’ over oasis enlarged and the vertical height of ‘humid island’ decreased with increase of surface temperature difference. The influence on ‘humid island effect’ was about an hour later than that on ‘cold island effect’. The updraft airflow over the oasis increased and the vertical velocity increased over the transition area above 1.5 km height with increase of buoyancy frequency. The symmetry of vertical circulation between oasis and desert decreased with increase of initial background wind speed, and the height of circulation center decreased and the strength weakened.

Key words: oasis effect, BALSUIS model, initial surface temperature difference, buoyancy frequency, background wind

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