九寨黄龙机场两次降雪过程对比分析

Comparative Analysis of Two Snowfall Processes in Jiuzhai Huanglong Airport

摘要: 本文利用欧洲中期预报中心发布的ERA5再分析资料、NCEP/NCAR再分析资料、气象常规资料、九寨黄龙机场月总薄等对九寨黄龙机场2020~2021年两次10月降雪过程的天气形势、物理量场等进行对比和诊断分析。两次降雪过程均由冷暖气团交汇引起，高层抽吸作用增强抬升运动有利于降雪的维持。水汽和降温是降雪两个必备的条件，两次过程分别随着水汽、降温条件的满足而开始。个例一降雪过程水汽条件好，且有较强的水汽积聚，降雪量大。600 hPa的−2℃线可作为九黄机场10月份降雪过程中低层降温的参考线。正压位涡正值的变化与降雪强度变化一致，降雪中心位于斜压位涡绝对值得到较大增长的区域；两次降雪过程九黄机场上空均有倾斜的上升气流存在。

Abstract: This article uses ERA5 reanalysis data, NCEP/NCAR reanalysis data, meteorological conventional data, and monthly total snowfall at Jiuzhai Huanglong Airport released by the European Centre for Medium Range Forecasting to compare and diagnose the weather patterns, physical quantities, and other factors of the two October snowfall processes at Jiuzhai Huanglong Airport from 2020 to 2021. Both snowfall processes are caused by the intersection of cold and warm air masses, and the enhanced suction effect of the upper level enhances the lifting motion, which is beneficial for maintaining snowfall. Water vapor and cooling are two essential conditions for snowfall, and the two processes begin with the satisfaction of water vapor and cooling conditions. Example 1: During the snowfall process, the water vapor conditions are good and there is a strong accumulation of water vapor, resulting in a large amount of snowfall. The −2˚C line at 600 hPa can serve as a reference line for lower level cooling during the snowfall process at Jiuhuang Airport in October. The change in the positive value of the positive pressure potential vortex is consistent with the change in snowfall intensity, and the snowfall center is located in the area where the absolute value of the oblique pressure potential vortex increases significantly; During the two snowfall processes, there were inclined updrafts over Jiuhuang Airport.