阿勒泰山脉对新疆北部地区强暴雪过程影响的数值模拟研究

Numerical Studies on the Effect of Altai Mountains on the Severe Snowstorm in the North of Xinjiang

利用中尺度数值模式WRFV3.1对2010年1月6—8日新疆阿勒泰地区的强暴雪过程进行了地形敏感性数值试验。结果表明,阿勒泰地形对此次暴雪过程的形成和发展有明显的作用:(1)削减阿勒泰地区地形20%会增加阿勒泰山脉东侧的降水,同时减少其西侧的降水;(2)对流层低层垂直速度的分布显示,在此次暴雪过程中,由于阿勒泰山脉的地形作用会在该地区诱发地形波,削减地形会减弱山脉地形波的强度;(3)削减阿勒泰地区的地形增强了对流层低层700 hPa的气旋式环流,而涡度场的表现则比较凌乱,同时也会对水汽场及云微物理量场产生影响。

The topographic sensitivity numerical experiments were conducted for the snowstorm which occurred in Ahai Region in Xinjiang during January 6-8,2010 with WRF model. The results showed that the Altai Mountains had obvious effect on the snowstorm. （1） The precipitation increased in the east and reduced in the west in Altai Mountains when the topographic height reduced about 20%. （2） The distribution of vertical velocity at the low levels in troposphere showed that the mountain wave will be induced by the Ahai Mountains during the snowstorm process and the intensity of the mountain wave decreased with the topographic height reduced about 20%. （3） The cyclonic circumfluence at 700 hPa increased, otherwise the vorticity had on regular characterristics, and also showed some effect on the fields of moisture and cloud microphysics when the topographic height was reduced.