天山山区暴雪过程水汽特征

Analysis of Water vapor during the snowstorms at the Tianshan Mountains

摘要:

运用NCEP/NCAR再分析资料,主要采用HYSPLIT模式模拟后向追踪了1991—2020年(1—12月)天山山区出现的45 次暴雪天气过程的水汽源地、水汽输送及其贡献。研究表明:天山山区暴雪过程水汽主要来自大西洋沿途得到阿拉伯海、红海、地中海等地水汽的补充；西边界、北边界中低层、南边界中高层为水汽输入,北边界输入最多。HYSPLIT 模式分析表明,来自欧洲和中亚的水汽主要输送至700hPa及以下；来自地中海和黑海及其附近、大西洋及其沿岸主要输送至700hPa以上；对流层低层集中了80%的水汽。各源地水汽随西风气流到达关键区后,主要沿偏西(西南)、西北路径输入暴雪区,500hPa偏西(西南)路径占主要地位,700hPa及以下西北路径输送的水汽占主导地位。基于上述特征,建立了天山山区暴雪过程水汽贡献的三维精细结构。

Abstract:

Using NCEP/NCAR reanalysis data, and the HYSPLIT model was mainly used to simulate the water vapor source, water vapor transport, and their contributions of 45 snowstorms weather processes which occurred at the Tianshan Mountains from 1991 to 2020. The results showed that: the water vapor during the snowstorms at the Tianshan Mountains mainly comed from the Atlantic Ocean, and which was supplemented by water vapor from Arabian Sea, the Red Sea, the Mediterranean Sea and other places and so on.The western boundary, the middle and lower layers of the northern boundary, and the middle and upper layers of the southern boundary were water vapor inputs, with the northern boundary having the most input. The HYSPLIT model analysis showed that water vapor from Europe and Central Asia was mainly transported to 700hPa and below; Mainly transported to over 700hPa from the Mediterranean and Black Sea, as well as from the Atlantic and its coasts; 80% of water vapor was concentrated in the lower troposphere. After the water vapor in each source area reaches the key area with the westerly airflow, it mainly enters the blizzard area along the westward (southwest) and northwest paths. The westward (southwest) path at 500hPa was the main path, and the water vapor transported by the northwest path at 700hPa and below was the dominant path. Based on the above features, the 3D structure of water vapor contribution during the snowstorms process at the Tianshan Mountains was established.