The Formation of Barrier Winds East of the Loess Plateau and Their Effects on Dispersion Conditions in the North China Plains

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• 作者：Xiao-Ming Hu ; Xingliang Li ; Ming Xue ; Dui Wu ; Jose D. Fuentes
• 关键词：Air pollution ; Barrier wind ; Dynamic modification process ; One ; layer slab model
• 刊名：Boundary-Layer Meteorology
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：161
• 期：1
• 页码：145-163
• 全文大小：3,175 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Meteorology and Climatology
  Atmospheric Protection, Air Quality Control and Air Pollution
  
• 出版者：Springer Netherlands
• ISSN：1573-1472
• 卷排序：161

文摘

The North China Plain (NCP) to the east of the Loess Plateau is one of the most heavily polluted areas in the world. Weak surface flow in the western part of the NCP exacerbates the air pollution in this region. Deceleration of low-level flow when approaching the Loess Plateau, together with enhanced roughness associated with large cities, were previously ascribed as the causes for low wind speeds in the NCP. Using numerical simulations with a one-layer dispersion model, we identify that dynamic modification of airflow by the Loess Plateau (not just simple deceleration due to mountain blocking) plays an important role in reducing the wind speed over the NCP. Dynamically-induced northerly barrier winds, superimposed on the prevailing southerly/south-easterly flow, reduce the wind speed in a 50–100 km wide region to the east of the Plateau, partially explaining the weak winds in the western part of the NCP. Poor dispersion conditions due to weak horizontal winds likely contribute to the accumulation of pollutants in this region.