An Examination of Boundary 1 Layer Structure under the Influence of the Gap Winds in Urumqi,China, during Air Pollution Episode in Winter
- 作者：Xia LiXiangao XiaYu XinYufen MaJing YangJinglin LiXinghua Yang
- 会议时间：2012-09-01
- 关键词：middle Tianshan Mountain pass ; gap wind ; elevated southeasterly gale (ESEG) ; tethered-sonde ; severe air pollution episodes
- 作者单位：Xia Li(Institute of Desert Meteorology,Urumqi,China Meteorology Administration,China;LAGEO,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China No.46,Jianguo Road,Urumqi,Xinjiang,China,830002)Xiangao Xia(LAGEO,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China)Yu Xin(Xinjiang Climatic Center,Urumqi,China)Yufen Ma,Xinghua Yang(Institute of Desert Meteorology,Urumqi,China Meteorology Administration,China)Jing Yang(Xinjiang Meteorological Science and Technological Service Center)Jinglin Li(Xinjiang Information Center of Developing Agriculture Network,Urumqi,24 qi,China)
- 母体文献：第29届中国气象学会年会论文集
- 会议名称：第29届中国气象学会年会
- 会议地点：沈阳
- 主办单位：中国气象学会
- 语种：chi
摘要
Tethered-sonde measurements of atmospheric profiles were performed at Urumuqi,capital of the Xinjiang Uyghur Autonomous Region of China,from 29 December 2008 to 14 January 2009.The data were used to examine the boundary layer structure during this severe air pollution period.Diurnal evolution of local wind flow near Urumqi was simulated using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5).Measurements from Operational radiosonde data showed that a southeasterly elevated low-level jet often intruded upon Urumqi through the middle Tianshan Mountain pass to the south of the city.The tethered-sonde measurements showed that calm and northwesterly winds prevailed near the surface in Urumqi,while the southeasterly winds of relatively higher speed were dominant above ~400 m.Both temperature inversion and humidity inversion frequently occur during day and nighttime.Temperature inversion intensity could sharply rise as the stronger elevated southeasterly gales (ESEGs) happened.Model simulations showed that the winds near the surface around Urumqi remained calm during nighttime and developed toward the mountains during daytime.As cool air flow in the basin confronted the southeasterly winds from the pass in the lower layer,they formed a convergence line around Urumqi city,which was not favor for dilution of air pollutants.