Journal of Arid Meteorology
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LV Xinsheng1,WAN Yu1,YIN Bingxia2,WANG Xu3,CAO Xing2
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吕新生1,万瑜1,尹冰霞2,王旭3,曹兴2
作者简介:
基金资助:
中国气象局预报员专项(CMAYBY2015-088)
Abstract:
Based on the observation data from automatic weather station, conventional observations, TBB from FY-2E and NCEP reanalysis data, a strong cold wave event which occurred in northern Xinjiang from 22 to 23 April 2014 was analyzed. The emphasis laid on change of temperature advection, water vapor, unstable condition and characteristics of cloud system evolution when temperature dropped sharply and heavy snowfall occurred. The results indicate that the strong cold ridge of the Caspian Sea was coincided with the European Ridge at earlier stage with the north jet stream extending from the polar region to 40°N, which led the polar cold air to move south and the west-Siberia trough to extend and deepen to the south. The European Ridge retreated to southeast that induced the Siberia cold air to move to the same direction in the late period, which resulted in the strong cold wave occurring in northern of Xinjiang. The cold advection in the middle and lower level rapidly preceded that in the upper level and entered the northern Xinjiang, and the north jet stream enhanced cold advection, which resulted in temperature dropping sharply. The sustained water vapor of south Aral Sea converged along the west and southwest airflow, which provided plentiful water for the snowstorm. The structure of lower-level convergence and upper-level divergence and strong ascending stream provided favorable dynamic condition for snowstorm. Snowfall was produced by cold-front. When the snowfall occurred, cloud top brightness temperature ranged from -44 to -32 ℃. The heavier the snowfall, the lower the cloud top brightness temperature was. The evolution of cloud top brightness temperature provided the reference basis for prediction of the snowfall intensity and snowfall area. Through comparing the EC and T639 results and qualitative and quantitative analysis, the numerical prediction model was insensitive to temperature dropping, while the EC model was superior to T639 in forecasting heavy snow area, it had certain guiding meaning on forecast of snowstorm area.
Key words: cold wave , cold advection , water vapory, diagnostic analysis
摘要:
选取区域自动气象站、常规高空和地面观测资料,FY-2E云图TBB资料及NCEP再分析资料,对2014年4月22—23日发生在新疆北部的强寒潮天气成因进行诊断,着重分析强降温和强降雪发生时温度平流、水汽和不稳定条件及云系演变特征。结果表明:前期里海脊发展与欧洲脊叠加,极地到40°N为强偏北急流,引导极区冷空气南下,使得西西伯利亚低槽向南加深。后期欧洲脊向东南衰退,推动西西伯利亚低槽快速东南移,寒潮爆发;中低层冷平流先于高层冷平流进入新疆北部,低空偏北急流促使冷平流强度加强,造成强降温;里咸海南侧的水汽沿着偏西和西南气流输送,为暴雪提供充沛的水汽条件;低层辐合、高层辐散和较强的垂直上升运动为暴雪的产生提供动力条件;降雪由冷锋云系造成,TBB在-44~-32 ℃之间,TBB越小,降雪越强,其演变特征可为降雪强度及暴雪落区的判断提供参考;通过EC、T639数值预报模式与预报、实况的定性和定量对比分析,模式对强天气的温度精细化预报敏感性较差,而EC模式降雪落区的预报优于T639,对暴雪落区预报具有一定的指导意义。
关键词: 寒潮, 冷平流, 水汽, 诊断
CLC Number:
P458.1+22
LV Xinsheng1,WAN Yu1,YIN Bingxia2,WANG Xu3,CAO Xing2. Diagnosis of a Strong Cold Wave Weather Process in Northern Xinjiang on 23 April 2014[J]. Journal of Arid Meteorology, DOI: 10.11755/j.issn.1006-7639(2017)-01-0082.
吕新生1,万瑜1,尹冰霞2,王旭3,曹兴2. 新疆北部一次强寒潮天气特征及成因[J]. 干旱气象, DOI: 10.11755/j.issn.1006-7639(2017)-01-0082.
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URL: http://www.ghqx.org.cn/EN/10.11755/j.issn.1006-7639(2017)-01-0082
http://www.ghqx.org.cn/EN/Y2017/V35/I1/82