基于西安咸阳机场近20年降水特征及一次短时强降水的分析

Analysis of Precipitation Characteristics and a Short-Term Heavy Precipitation in Xianyang Airport of Xi’an in Recent 20 Years

摘要: 利用ERA5逐小时再分析资料及民航西北空管局气象中心观测室编制的观测年总簿、月总簿，分析了西安咸阳机场近20年降水的时间分布特征，结果表明，2001~2020年，西安咸阳机场逐年降水量呈现出明显的波动变化和枯丰年交替的现象，降水量总体呈微弱减少趋势；年均降水量为546.03 mm，降水量最多的2003年达1072 mm，降水量最少的2016年仅394.9 mm；各季降水量由多到少依次为夏季 > 秋季 > 春季 > 冬季。此外，通过对西安咸阳机场一次短时强降水的分析，并结合天气对民航运行的影响，结果表明，副高边缘配合低层切变辐合系统是造成此次短时强降水的原因。发生强降水的区域具有明显的垂直速度负值区和明显的正涡度中心带，散度场的低空辐合、高空辐散结构及其演变与强降水的发生、发展密切相关，研究结果有助于增强夏季短时强降水的临近预测能力和航空气象保障能力。

Abstract: Based on the hourly reanalysis data of ERA5 and the annual and monthly records compiled by the meteorological center of Northwest Air Traffic Control Bureau of CAAC, the temporal distribution characteristics of precipitation in Xi’an Xianyang Airport in recent 20 years are analyzed. The results show that the annual precipitation of Xi’an Xianyang Airport shows obvious fluctuation and alternation of dry and rainy years from 2001 to 2020, and the precipitation shows a weak decreasing trend; the average annual precipitation is 546.03 mm, with 1072 mm in 2003 and 394.9 mm in 2016. The order of precipitation in each season is summer > autumn > spring > winter. In addition, through the analysis of a short-term heavy rainfall in Xi’an Xianyang Airport, combined with the impact of weather on civil aviation operation, the results show that the edge of subtropical high combined with low-level shear convergence system is the cause of the short-term heavy rainfall. The low-level convergence, high-level divergence and their evolution of divergence field are closely related to the occurrence and development of heavy rainfall. The research results are helpful to enhance the ability of near prediction and aviation meteorological support of short-term heavy rainfall in summer.