摘要
利用ECMWF细网格新资料和区域自动站等资料,分析2011—2014年乌鲁木齐9次典型东南大风天气过程。结果表明:东南大风高空环流形势存在2种特殊的形态,锋前减压加回流型和脊中配合低槽型。为了研究空间尺度较为精细的地面中尺度气压场,利用ECMWF细网格资料将海平面气压场分为4型:两高两低型、一高一低型、两高一低型和高低压带状型,其中前两者较常见;高低压带状型东南大风具有持续时间长,间歇性的特点。当存在南高北低,东高西低的海平面气压差时,东南大风开始出现,随风力增大,在乌鲁木齐附近存在东北或西南方向气压梯度,阈值不小于8 h Pa,最大在15 h Pa左右;当气压梯度维持均衡且大于10 h Pa时,将出现持续时间长或断续出现风力强劲的东南大风。通过气压场的中尺度特征,分析了乌鲁木齐东南大风的环流特征和预报指标,为东南大风的起止时间、风速量级及落区的预报提供了参考依据。
Based on ECMWF refined net numerical forecast data and AWOS data,the 9 southeast gales occurred in Urumqi during the period of 2011- 2014 were analyzed. The results indicated that there were two especial patterns of upper air current： One was the long-narrow ridge of decompression before front,and another was a trough in ridge. In order to study the spatial scale of refined surface,the mesoscale sea-level pressure fields were divided into 4 types using ECMWF fine grid data： two-high clipping the low type,two-high and two-low type,one-high and one-low type,and high-low pressure belt type. The two-high and two-low type and one-high and one-low type are more common,while two other types are rare. High-low pressure belt type was characterized by the long duration and intermittence. Southeast gale over the urban area of Urumqi was researched. Along with the increase of wind speed,there was a pressure gradient at the northeast or southwest direction around Urumqi,the threshold value was no less than 8 h Pa,and the maximum was about 15 h Pa. When a balance of pressure gradient was maintained and was higher than 10 h Pa,a southeast gale with long duration or intermittent high wind speed would occur. The circulation features and the forecast indexes of southeast gale in Urumqi were analyzed to provide a reference for forecasting the starting and ending time,wind speed and area of southeast gale.
出处
《干旱区研究》
CSCD
北大核心
2016年第4期724-731,共8页
Arid Zone Research
基金
中央级公益性科研院所基本科研业务费专项(IDM201201)
中国气象局预报员东南大风专项(CMAYBY2013-078)
新疆维吾尔自治区气象局青年基金项目(201234)
关键词
大风天气
细网格
气压场
分型
乌鲁木齐
southeast gale
refined net
pressure field
circulation
Urumqi
