【摘要】 根据常规观测资料和美国NCEP/NCAR提供的1°×1°6 h再分析资料,对2006年4月9—11日我国西北地区大范围沙尘天气过程环流动力特征等进行了分析。结果表明,高空急流、相对涡度和垂直速度在沙尘暴发生发展的不同时期有着较好的配置,沙尘暴发展的强盛期,相对涡度和垂直速度的不对称结构亦较强,在高空急流中心下方存在一个北部上升南部下沉的反环流,沙尘暴主要发生在高空急流中心南侧37°—44°N范围内,即在反环流区域的下沉气流区和热低压北部上升气流区。更多还原

【Abstract】 The observed data and the NCEP/NCAR 1°× 1° 6-hour reanalysis data were used to analyze the circulation dynamical structure of dust storm processes during April 9-11,2006 in Northwest China.The results show that upper jet flow,relative vorticity,pressure vertical velocity differently matched in various periods of dust storm development,and their values and spatial distributions were well-corresponding to the forming,developing and decaying of dust event.In strong stage of dust storm,the asymmetric structure of relative vorticity was enhanced.There was a couter-circulation at the lower side of the centre of the upper jet flow,and dust storms mainly occurred in the area of 37° N to 44° N,just the downdraught region of the couter-circulation.更多还原