| 摘要: |
| 利用常规观测资料和NCEP 1°×1°再分析资料,通过对发生在江苏的三次不同量级的区域性暴雪、大雪和中雪过程典型个例进行对比分析,发现降雪时,700hPa低空急流的位置和强度是影响降雪量级的主要因素之一；降雪区上空涡度的垂直分布遵循低层负涡度、中层正涡度和高层负涡度的配置,暴雪时正涡度强且正涡度区最为深厚,动力抬升作用强,中雪发生时正涡度区相对最为浅薄,不利于形成强辐合抬升,动力抬升作用弱。且暴雪和大雪发生时基本上整层都为垂直螺旋度正值区,中雪时没有出现明显的正值区；暴雪和大雪过程时中低层都具有明显的逆温层,中高层西南急流造成的对流层中层的爆发性增温是逆温层形成的关键,中雪发生时不一定有逆温层结；降雪强度与湿位涡分量绝对值存在一定的正相关关系。 |
| 关键词: 不同量级;区域降雪;对比分析 |
| DOI： |
| 投稿时间：2020-01-20修订日期：2020-03-26 |
| 基金项目:江苏省气象局预报员专项(JSYBY201911)；泰州市科技项目(TS201928)共同资助 |
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| WANG Xi,ZHANG Ling, ZHENG Wei, YANG Mengxi |
| WANG XI,ZHANG LING,ZHENG WEI,YANG MENGXI |
| (TaiZhou Meteorology Administration) |
| Abstract: |
| Based on the conventional observation data and NCEP 1 °× 1 ° reanalysis data, three typical cases of regional blizzard, heavy snow and moderate snow in Jiangsu Province are compared and analyzed. It is found that the location and intensity of 700hPa low-level jet is one of the main factors affecting the magnitude of snowfall, and the vertical distribution of the vorticity over the snowfall area follows the low-level negative vorticity and medium level The configuration of positive vorticity and negative vorticity in the upper layer shows that during blizzard, the positive vorticity is strong and the positive vorticity area is the deepest, and the dynamic uplift is strong, while the positive vorticity area is relatively shallow when the middle snow occurs, which is not conducive to the formation of strong convergence and uplift, and the dynamic uplift is weak. In addition, when Blizzard and Blizzard occur, the whole layer is basically positive area of vertical helicity, and there is no obvious positive area in moderate snow; in the process of Blizzard and blizzard, there is an obvious inversion layer in the middle and low layers, and the explosive increase of temperature in the middle troposphere caused by southwest jet in the middle and high layers is the key to the formation of inversion layer, and there is not necessarily inversion layer knot in the occurrence of moderate snow; the intensity of snowfall and the component of moist potential vorticity are absolute There is a positive correlation between the values. |
| Key words: different magnitude; regional snowfall; comparative analysis |
