【摘要】 利用常规天气资料和数值预报产品,应用天气分析和诊断分析方法,从环流背景、地面系统演变、物理场特征等方面,对2008-12-02—04寒潮天气进行了分析,并就T213、EC数值预报模式模拟结果进行了检验.结果表明,此次寒潮过程按照宁夏地区对寒潮天气的分型标准可归于乌拉尔山脊东移型,500,700 hPa高空环流形势均为一脊一槽型,在贝湖一带维持一明显的低涡;乌山脊稳定维持,有利于冷空气在脊前堆积加强,为强冷空气爆发创造了有利条件;500,700 hPa温度场冷中心强度分别达到-48℃,-36℃;寒潮前期,由于海平面气压场,我区处于热低压控制,在冷空气来临前出现了明显的回暖;伴随冷空气南压,地面气压场明显升高,冷高压中心值最强达到1 065 hPa,冷高压移动路径为西北东南向;从温度平流场来看,此次寒潮过程是北部强冷平流区南压造成;寒潮前期,中低层存在明显的正涡度平流,有利于地面热低压的发展和潮前回暖,强负涡度平流东移南压加强了下沉运动,有利于冷空气下沉爆发;T213、EC模式对造成此次寒潮过程的天气系统均做了较为准确的预报,2种数值预报模式在72 h时段内预报能力都较强,EC略优于T213.更多还原

【Abstract】 Using conventional observation data and numerical prediction products,applying weather analysis and diagnostic analysis methods,a cold wave event occurred during December 2nd-4th in 2008 was analyzed,and the prediction abilities of T213 and EC numerical prediction model were tested.The result shows: this cold wave event belongs to the Ural mountain pledge moving toward east type,circulation at 500 hPa,700 hPa is one high ridge and one low trough,there was a obvious low vortex which maintained over Baikal lake;the maintains of Ural high ridge was beneficial to the cold air being piled up and strengthened,and supplied beneficial conditions for the bursts of cold air;the cold center at 500 hPa and 700 hPa reached to-48 ℃ and-36 ℃;during the prophase of cold wave,Ningxia region was controlled by warm low pressure,and temperature increased remarkably;along with the cold air bursting toward south,ground pressure field increased obviously,the pressure value at high pressure center reached to 1 065 hPa,the moving track of cold high pressure center was from north-west to south-east;at temperature advection field,the moving south of strong cold temperature advection caused the cold wave event;at the earlier stage,there was remarkable plus vortex advection in middle and low level,this situation is beneficial to strengthen warm low pressure of ground surface and temperature rise,southern movement of strengthened minus vortex advection is beneficial to the burst of cold air;the numerical prediction model T213 and EC predicted this cold wave events accurately,their prediction ability was strong in 0-72 hours stage,and EC was a little better than T213.更多还原