甘肃中部“2·18”暴雪物理特征研究

Research on Physical Characteristics of “2.18” Blizzard in Central Gansu Province

利用地面与高空实况观测资料,从高低空地面环流形势和部分物理量反映等方面对甘肃省中部2013年2月17—18日暴雪天气进行综合分析。结果表明:此次暴雪发生在新疆北部冷空气东移南下、高原上有强盛西南暖湿气流配合的有利环流形势下,主要降雪区与500 h Pa辐合线相一致;水汽输送主要集中在500 h Pa附近,700 h Pa偏南气流的水汽输送只是有益的补充;对流层中层500 h Pa有较深厚的上升运动,且上升运动极值出现和维持的时间与主要降雪时段一致;暴雪发生前在甘肃中部有较长时间的能量积聚,而冷空气的突然加速南压触发了本次暴雪。

By using the ground and high altitude data, and based on the reaction of high and low altitude circulation situation and some physical quantities, this study analyzed the blizzard occurring in central Gansu Province from February 17 th to February 18 th, 2013. The result showed that this blizzard occurred in this circulation situation：The cold air was eastward and moving down from north Xinjiang, running up against the strong southwest warm current from plateau; The major snow area was consistent with the 500 h Pa convergence line, the vapor transportation focused on 500 h Pa, and supplied on 700 h Pa; A strong ascending motion appeared in the mid tropospheric near 500 h Pa, and the appearance over time of extreme value was consistent with the snowfall time; There was a longer period of energy accumulation before the blizzard occurred, and the sudden acceleration of cold air triggered the blizzard.