一次昌吉地区春季强寒潮天气分析及数值模拟

先基于常规天气观测资料和美国FNL1°×1°逐6h再分析资料，对2014年4月23~24日昌吉地区一次寒潮天气过程进行分析和总结，而后利用WRF3.7中尺度数值模式对10米风场和地形作用进行分析，结果表明：（1）这次寒潮天气过程出现在欧洲高压脊东南衰退、西西伯利亚低槽东南下进入新疆爆发的大尺度环流背景下。（2）这次强寒潮过程的高位涡强冷空气来自欧亚北部和北极地区的平流层下部和对流层上部。（3）本次天气受西南水汽通道影响明显，从印度洋经过长途跋涉经过四川盆地以东地区，沿着西北方向在输送中绕过青藏高原，地形阻挡引起的损失相对较少，顺着甘肃地区到达41°N附近与北支带来的水汽相遇后向西输送进入昌吉地区。（4）低层强西北风急流向山脉辐合，造成暖湿气流在天山迎风坡强烈爬升，是暴雪发生的触发机制。通过地形敏感性试验表明天山地形的抬升作用减弱所引起的降水变小。

Analysis and Numerical Simulation of Strong Cold Wave in Changji Area

Based on the conventional weather observation data and the US FNL 1 ° × 1 ° 6h reanalysis data, a cold wave process in Changji area was analyzed and summarized from April 23 to April 24, 2014, and then t the wind filed features and the topographic function on the cold wave were futher studied through conducting a set of numerical experiments using WRF3.7. The results indicate that, firstly, the cold-wave event occurred in the context of the southeastern depression of the European ridge of high pressure and the large-scale circulation of the eruption of Xinjiang in the southeast of the western Siberian low trough. Secondly, the high vorticity cold air is from the lower stratosphere and the upper troposphere in northern Eurasia and Arctic regions. Thirdly, the weather affected by the southwest water vapor channel, from the Indian Ocean after a long journey through the east of Sichuan basin, along the northwest in the transportation around the Tibetan plateau, the terrain block caused by the loss is relatively small, down near region in Gansu province reached 41 ° N and northern branch of vapor is transported to the west after meet in Changji areas. Finally, the strong northwesterly winds converge to the mountains, resulting in a strong climax of the warm and humid airflow in the windward slope of the Tianshan Mountains, which is the triggering mechanism of blizzard. Based on terrain sensitivity test results show that the precipitation is weakened by the uplift effect of the Tianshan mountain.