摘要
受高空槽和强冷空气影响,2023年4月20日至22日四川省及其周围地区出现明显强降温天气.为了探究地形重力波拖曳作用对复杂地形区低温天气的影响机理,利用再分析资料,结合西南区域业务模式开展地形重力波参数化敏感性试验.分析模拟结果发现,地形重力波拖曳(GWD)试验可有效改善控制试验在川西高原中部及四川盆地的温度模拟暖偏差.为了探究暖偏差改善的原因,分析500 hPa风场,发现地形重力波拖曳使青藏高原中部风速减弱,高原南坡西风绕流增强,从而使位于青藏高原东南坡的川西地区风速增强.基于Barnes滤波的尺度分离结果显示,大尺度风场的变化是模拟风场变化的主要原因,地形重力波拖曳试验中高原南坡西南风速的增加使冷平流增强,是川西高原暖偏差改善的主要原因,而四川盆地暖偏差改善是由850 hPa盆地东南部暖平流减弱导致的.
Affected by the upper-level trough and strong cold air,from April 20th to 22nd,2023,significant strong cooling weather occurred in Sichuan Province and its surrounding areas.To explore the impact and mechanism of the orographic gravity wave parameterization scheme on low temperature in complex terrain areas,combining reanalysis data with SWC-WARR(South West Center-WRF ADAS Rapid Refresh),sensitivity experiments of the orographic gravity wave parameterization were carried out.By analyzing the simulation results,it was found that the GWD experiment could effectively improve the warm bias in temperature simulation of the CTL experiment in the central part of the western Sichuan Plateau and the Sichuan Basin.To explore the reasons for the improvement of the warm bias,by analyzing the 500 hPa horizontal wind field,it was found that the drag weakened the wind speed in the central part of the Qinghai-Xizang Plateau(QXP)and enhanced the westerly flow around the southern slope of the QXP,thus strengthening the wind speed in the western Sichuan Plateau.After scale separation using Barnes filtering,it was found that the change in the large-scale wind field was the main cause of the change in the simulated wind field.The increase in the southwesterly wind speed on the southern slope of the QXP in the GWD experiment led to an increase in cold advection,which was the main reason for the improvement of the warm bias in the western Sichuan Plateau,while the improvement of the warm bias in the Sichuan Basin was caused by the weakening of the warm advection in the southeastern part of the basin at 850 hPa.
作者
季玉枝
艾真珍
衡志炜
徐昕
Ji Yuzhi;Ai Zhenzhen;Heng Zhiwei;Xu Xin(Hebei Meteorological Observatory,Hebei Meteorological Service,Shijiazhuang,050021,China;Key Laboratory of Mesoscale Severe Weather,Ministry of Education,School of Atmosphere Sciences,Nanjing University,Nanjing,210023,China;Institute of Plateau Meteorology,CMA,Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu,610072,China)
出处
《南京大学学报(自然科学版)》
北大核心
2025年第3期353-362,共10页
Journal of Nanjing University(Natural Science)
基金
国家重点研发计划(2023YFC3007502)
作者简介
通信联系人:徐昕,E-mail:xinxu@nju.edu.cn
